:root {
  color-scheme: light;
  --bg: #e8edef;
  --surface: #f7f9fa;
  --surface-soft: #e2eaec;
  --text: #263238;
  --muted: #607078;
  --line: #cbd6da;
  --control-line: #74858c;
  --primary: #167d88;
  --primary-strong: #0f6570;
  --primary-soft: #dff1f2;
  --accent: #e9a23b;
  --focus: #8a5200;
  --on-primary: #ffffff;
  --on-danger: #ffffff;
  --diagram-device-bg: #263238;
  --diagram-device-text: #f2f6f7;
  --diagram-arrow: #075f6a;
  --success: #2a7041;
  --success-soft: #e6f4ea;
  --danger: #b63f3f;
  --danger-soft: #fbeaea;
  --shadow: 0 8px 24px rgba(31, 54, 61, .07);
  --sidebar-open: 220px;
  --sidebar-closed: 64px;
  --bottom-nav: 62px;
}

:root[data-theme="dark"] {
  color-scheme: dark;
  --bg: #182126;
  --surface: #222d33;
  --surface-soft: #26383c;
  --text: #e8eef0;
  --muted: #aebcc2;
  --line: #3b4a51;
  --control-line: #74858c;
  --primary: #71c8d0;
  --primary-strong: #9bdbe0;
  --primary-soft: #29474b;
  --accent: #f2b85f;
  --focus: #f2b85f;
  --on-primary: #102126;
  --on-danger: #2b1515;
  --diagram-device-bg: #2a3b43;
  --diagram-device-text: #d5e1e5;
  --diagram-arrow: #b9f1f4;
  --success: #80c995;
  --success-soft: #294434;
  --danger: #f29a9a;
  --danger-soft: #4b2c2c;
  --shadow: 0 8px 24px rgba(0, 0, 0, .18);
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Yu Gothic", "Meiryo", sans-serif;
  font-size: 15px;
  line-height: 1.6;
}
button, input, select, textarea { font: inherit; }
button, a { -webkit-tap-highlight-color: transparent; }
a { color: var(--primary-strong); }
button:focus-visible, a:focus-visible, input:focus-visible, select:focus-visible, textarea:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 3px;
}
.skip-link { position: fixed; left: 12px; top: -80px; z-index: 200; padding: 10px 14px; background: var(--surface); border-radius: 10px; }
.skip-link:focus { top: 12px; }

.app-shell { min-height: 100vh; }
.sidebar {
  position: fixed; inset: 0 auto 0 0; z-index: 60; width: var(--sidebar-open);
  background: var(--surface); border-right: 1px solid var(--line); padding: 18px 12px;
  display: flex; flex-direction: column; overflow: hidden;
}
body.sidebar-collapsed .sidebar { width: var(--sidebar-closed); }
body.ui-ready:not(.sidebar-collapsed) .sidebar { width: var(--sidebar-open); }
:root[data-sidebar-state="collapsed"] .sidebar { width: var(--sidebar-closed); }
.brand { display: flex; align-items: center; gap: 10px; min-height: 46px; margin-bottom: 16px; color: var(--text); text-decoration: none; white-space: nowrap; }
.brand-mark { width: 38px; height: 38px; border-radius: 12px; display: block; object-fit: cover; flex: 0 0 auto; }
:root[data-theme="light"] .brand-mark { content: url("/assets/icon-options/cable-n-light.svg"); }
.brand-text { font-weight: 750; letter-spacing: .02em; }
.side-nav { display: grid; gap: 5px; }
.nav-link, .sidebar-toggle {
  min-height: 46px; display: flex; align-items: center; gap: 12px; padding: 8px 11px;
  border-radius: 12px; border: 0; background: transparent; color: var(--muted); text-decoration: none; cursor: pointer; white-space: nowrap; width: 100%;
}
.nav-link:hover, .sidebar-toggle:hover, .nav-link[aria-current="page"] { background: var(--primary-soft); color: var(--primary-strong); }
.nav-icon { width: 24px; text-align: center; font-size: 19px; flex: 0 0 auto; }
.sidebar-toggle { margin-top: auto; }
body.sidebar-collapsed .nav-label, body.sidebar-collapsed .brand-text { opacity: 0; pointer-events: none; }
:root[data-sidebar-state="collapsed"] .nav-label,
:root[data-sidebar-state="collapsed"] .brand-text { opacity: 0; pointer-events: none; }

.main-content { margin-left: var(--sidebar-open); min-height: 100vh; }
body.sidebar-collapsed .main-content { margin-left: var(--sidebar-closed); }
body.ui-ready:not(.sidebar-collapsed) .main-content { margin-left: var(--sidebar-open); }
:root[data-sidebar-state="collapsed"] .main-content { margin-left: var(--sidebar-closed); }
.content-wrap { width: min(100% - 32px, 980px); margin: 0 auto; padding: 24px 0 48px; }
.reading-width { max-width: 760px; margin-inline: auto; }

.page-kicker { color: var(--primary-strong); font-weight: 750; font-size: 14px; margin: 0 0 4px; }
h1, h2, h3 { line-height: 1.35; }
h1 { font-size: clamp(24px, 3vw, 34px); margin: 0 0 8px; letter-spacing: -.02em; }
h2 { font-size: clamp(20px, 2.2vw, 25px); margin: 0 0 12px; }
h3 { font-size: 17px; margin: 0 0 5px; }
.lead { color: var(--muted); font-size: 16px; margin: 0 0 18px; }
.muted { color: var(--muted); }
.meta { color: var(--muted); font-size: 13px; display: flex; gap: 12px; flex-wrap: wrap; }

.card {
  background: var(--surface); border: 1px solid var(--line); border-radius: 17px;
  padding: 20px; box-shadow: var(--shadow);
}
.card + .card { margin-top: 16px; }
.grid > .card + .card { margin-top: 0; }
.grid { display: grid; gap: 16px; }
.grid-2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid-align > .card { height: 100%; }
.hero { padding: 28px; background: linear-gradient(135deg, var(--surface), var(--surface-soft)); }
.hero-actions, .button-row { display: flex; gap: 10px; flex-wrap: wrap; align-items: center; }
.section { margin-top: 26px; }
.section-head { display: flex; align-items: end; justify-content: space-between; gap: 16px; margin-bottom: 12px; }
.section-head h2 { margin: 0; }

.ad-placeholder {
  min-height: 112px;
  margin-top: 18px;
  border: 1px dashed var(--control-line);
  border-radius: 14px;
  background: var(--surface-soft);
  color: var(--muted);
  display: grid;
  place-content: center;
  justify-items: center;
  gap: 2px;
  padding: 16px;
  text-align: center;
}
.ad-placeholder span { font-size: 11px; letter-spacing: .12em; }
.ad-placeholder strong { color: var(--text); font-size: 14px; }
.ad-placeholder small { font-size: 12px; }
.ad-placeholder-in-list { grid-column: 1 / -1; }
.ad-slot {
  width: 100%;
  min-width: 0;
  min-height: 90px;
  margin-top: 18px;
  overflow: hidden;
}
.ad-slot-in-list { grid-column: 1 / -1; }
.ad-slot .adsbygoogle { min-width: 0; }

.button {
  min-height: 44px; border: 1px solid transparent; border-radius: 12px; padding: 10px 16px;
  background: var(--primary); color: var(--on-primary); font-weight: 700; text-decoration: none; cursor: pointer; display: inline-flex; align-items: center; justify-content: center; gap: 8px;
}
.button:hover { background: var(--primary-strong); }
.button.secondary { background: var(--surface); color: var(--primary-strong); border-color: var(--control-line); }
.button.ghost { background: transparent; color: var(--primary-strong); border-color: var(--control-line); }
.button.danger { background: var(--danger); color: var(--on-danger); }
.button[disabled] { opacity: .55; cursor: not-allowed; }

.progress-track { height: 10px; background: var(--control-line); border-radius: 99px; overflow: hidden; }
.progress-bar { height: 100%; width: var(--progress, 0%); background: var(--primary); border-radius: inherit; transition: width .25s ease; }
.progress-line { display: flex; justify-content: space-between; gap: 12px; margin-bottom: 7px; }
.progress-detail { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 12px; align-items: center; margin-top: 8px; color: var(--muted); font-size: 13px; }
.progress-next { margin: 8px 0 0; font-size: 14px; }
.text-link { font-weight: 700; white-space: nowrap; }
.recommendation-card { display: flex; flex-direction: column; align-items: flex-start; }
.recommendation-card h2 { margin-top: 9px; }
.recommendation-card .button { margin-top: auto; }

.menu-card { color: var(--text); text-decoration: none; display: block; }
.menu-card:hover { border-color: var(--primary); transform: translateY(-1px); }
.menu-card .menu-symbol { width: 42px; height: 42px; border-radius: 13px; background: var(--primary-soft); color: var(--primary-strong); display: grid; place-items: center; margin-bottom: 12px; font-size: 21px; }
.learning-entry-grid { margin-top: 4px; }
.learning-entry-grid + .progress-card { margin-top: 18px; }
.status-badge { display: inline-flex; align-items: center; min-height: 26px; border-radius: 99px; padding: 2px 10px; background: var(--primary-soft); color: var(--primary-strong); font-size: 13px; font-weight: 750; }
.status-badge.complete { background: var(--success-soft); color: var(--success); }

.lesson-list { display: grid; gap: 10px; }
.lesson-row { display: flex; align-items: center; gap: 14px; color: var(--text); text-decoration: none; }
.lesson-index { width: 36px; height: 36px; border-radius: 50%; display: grid; place-items: center; background: var(--primary-soft); color: var(--primary-strong); font-weight: 800; flex: 0 0 auto; }
.lesson-copy { flex: 1; min-width: 0; }
.lesson-copy strong { display: block; }
.lesson-copy span { color: var(--muted); font-size: 14px; }

.breadcrumbs { display: flex; flex-wrap: wrap; gap: 6px; color: var(--muted); font-size: 13px; margin-bottom: 16px; }
.breadcrumbs a { color: inherit; }
.lesson-block { margin-top: 18px; }
.hero .hero-actions .secondary { display: none; }
.hero [data-home-primary] { visibility: hidden; }
.hero [data-home-primary].is-ready { visibility: visible; }
.abbreviation-note {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 14px;
  margin: -2px 0 10px;
  color: var(--muted);
  font-size: 13px;
}
.abbreviation-note span {
  display: inline-flex;
  gap: 4px;
  align-items: baseline;
}
.abbreviation-note strong { color: var(--primary-strong); }
.step-list { counter-reset: lesson-step; display: grid; gap: 10px; }
.step-item { position: relative; padding-left: 48px; min-height: 40px; }
.step-item::before { counter-increment: lesson-step; content: counter(lesson-step); position: absolute; left: 0; top: 1px; width: 34px; height: 34px; border-radius: 50%; background: var(--primary); color: var(--on-primary); display: grid; place-items: center; font-weight: 800; }
.mechanism-note { margin-top: 14px; padding: 13px 15px; border-left: 4px solid var(--accent); border-radius: 0 12px 12px 0; background: var(--surface-soft); }
.mechanism-note h3 { font-size: 15px; }
.mechanism-note p { margin: 0; }
.point-list, .summary-list { margin: 0; padding-left: 22px; }
.point-list li, .summary-list li { margin: 7px 0; }

.term-wrap { display: inline; }
.term-trigger { padding: 0 2px; border: 0; border-bottom: 2px dotted var(--primary); background: transparent; color: inherit; font: inherit; font-weight: 700; cursor: help; }
.term-trigger::after { content: "?"; display: inline-grid; place-items: center; width: 15px; height: 15px; margin-left: 3px; border-radius: 50%; background: var(--primary-soft); color: var(--primary-strong); font-size: 10px; vertical-align: 2px; }
.term-dialog { width: min(380px, calc(100vw - 32px)); padding: 16px; border: 1px solid var(--line); border-radius: 14px; background: var(--surface); box-shadow: 0 18px 60px rgba(0,0,0,.28); color: var(--text); font-size: 14px; line-height: 1.55; }
.term-dialog::backdrop { background: rgba(16, 29, 34, .58); }
.term-dialog-head { display: flex; align-items: center; justify-content: space-between; gap: 12px; }
.term-dialog-head strong { font-size: 18px; }
.term-dialog p { margin: 12px 0; }
.term-dialog a { font-weight: 700; }
.glossary-list { display: grid; gap: 14px; }
.glossary-card { scroll-margin-top: 18px; }
.glossary-card:target { border-color: var(--primary); box-shadow: 0 0 0 3px var(--primary-soft), var(--shadow); }

.diagram { margin-top: 16px; background: var(--surface-soft); border: 1px solid var(--line); border-radius: 15px; padding: 18px; }
.network-line { display: flex; align-items: center; justify-content: center; gap: 10px; flex-wrap: wrap; text-align: center; }
.device { min-width: 105px; padding: 11px 12px; border-radius: 12px; background: var(--surface); border: 1px solid var(--line); font-weight: 700; }
.device small { display: block; color: var(--muted); font-weight: 500; }
.connector { color: var(--primary-strong); font-weight: 800; }
.ip-topology { display: grid; grid-template-columns: minmax(130px, 1fr) minmax(150px, 1.2fr) minmax(145px, 1fr) auto minmax(130px, 1fr); gap: 9px; align-items: center; }
.ip-endpoint { min-width: 0; text-align: center; }
.ip-endpoint strong { display: block; margin-bottom: 5px; }
.ip-flow { display: grid; grid-template-columns: 1fr auto; gap: 3px 8px; align-items: center; color: var(--primary-strong); text-align: center; }
.ip-flow span { font-weight: 800; }
.ip-flow small { grid-column: 1; padding: 7px; border: 1px solid var(--primary); border-radius: 9px; background: var(--surface); color: var(--text); line-height: 1.45; }
.ip-flow b { grid-column: 2; grid-row: 1 / 3; font-size: 24px; }
.ip-flow.simple { display: block; }
.ip-delivery-map { display: grid; grid-template-columns: minmax(0, .85fr) minmax(0, 1fr) minmax(0, 1.25fr) minmax(0, .9fr); gap: 14px; align-items: center; }
.ip-delivery-map > * { position: relative; min-width: 0; overflow-wrap: anywhere; }
.ip-delivery-map > :not(:last-child)::after { content: "→"; position: absolute; top: 50%; right: -17px; transform: translateY(-50%); color: var(--primary-strong); font-size: 19px; font-weight: 900; }
.ip-delivery-device { display: grid; gap: 6px; padding: 11px; border: 1px solid var(--line); border-radius: 11px; background: var(--surface); text-align: center; }
.ip-delivery-device.destination { border-color: var(--primary); }
.ip-label { padding: 5px; border-radius: 7px; background: var(--primary-soft); color: var(--primary-strong); font-weight: 800; font-size: 12px; }
.ip-delivery-device small { color: var(--muted); }
.ip-packet { display: grid; gap: 5px; padding: 10px; border: 2px solid var(--primary); border-radius: 11px; background: var(--surface); text-align: center; }
.ip-packet > small { color: var(--muted); }
.ip-packet span { display: grid; gap: 2px; padding: 6px; border-radius: 7px; background: var(--surface-soft); font-size: 11px; }
.ip-packet b { color: var(--primary-strong); }
.ip-router-decision { display: grid; gap: 4px; padding: 11px; border-radius: 11px; background: var(--diagram-device-bg); color: var(--diagram-device-text); text-align: center; }
.ip-router-decision > small { color: inherit; opacity: .78; }
.ip-router-decision > div { display: grid; gap: 5px; margin-top: 5px; }
.ip-router-decision span, .ip-router-decision b { padding: 6px; border: 1px solid #596d75; border-radius: 7px; font-size: 10px; }
.ip-router-decision span { opacity: .65; }
.ip-router-decision b, .ip-router-decision span.is-route { border-color: var(--primary); opacity: 1; background: color-mix(in srgb, var(--primary) 16%, var(--diagram-device-bg)); }
.ip-reply-note { display: flex; gap: 8px; margin-top: 11px; padding: 10px 12px; border-left: 4px solid var(--accent); border-radius: 8px; background: color-mix(in srgb, var(--accent) 9%, var(--surface)); }
.ip-reply-note span { color: var(--muted); }
.network-device { padding: 13px 10px; border-radius: 12px; background: var(--diagram-device-bg); color: var(--diagram-device-text); text-align: center; }
.network-device strong, .network-device small { display: block; }
.network-device small { margin-top: 5px; color: inherit; opacity: .8; line-height: 1.45; }
.diagram-caption { margin: 0 0 14px; text-align: center; color: var(--muted); font-weight: 700; }
.vlan-topology { display: grid; grid-template-columns: minmax(145px, 1fr) auto minmax(180px, 1.15fr) auto minmax(145px, 1fr); gap: 10px; align-items: center; }
.vlan-box { border: 2px solid var(--primary); border-radius: 14px; padding: 12px; text-align: center; }
.vlan-admin { border-color: var(--accent); }
.vlan-box > strong, .switch-box > strong { display: block; margin-bottom: 6px; }
.endpoint-list { display: grid; gap: 7px; margin-top: 10px; }
.endpoint-list > span { padding: 7px; border-radius: 9px; background: var(--surface); border: 1px solid var(--line); font-weight: 750; }
.endpoint-list small { display: block; color: var(--muted); font-weight: 500; }
.topology-link { color: var(--primary-strong); font-size: 12px; font-weight: 800; text-align: center; line-height: 1.25; }
.switch-box { padding: 14px; border-radius: 12px; background: var(--diagram-device-bg); color: var(--diagram-device-text); text-align: center; font-weight: 750; }
.switch-box small { display: block; color: inherit; opacity: .78; font-weight: 500; }
.switch-ports { display: grid; grid-template-columns: repeat(4, 1fr); gap: 4px; margin-top: 10px; }
.switch-ports span { padding: 5px 2px; border: 1px solid transparent; border-radius: 6px; color: #102126; }
.switch-ports .normal-port { border-color: #83a9ba; background: #c7dde6; color: #102126; }
.sales-port { background: #8ed9ff; }
.admin-port { background: #f6c56e; }
.diagram-result { margin: 14px 0 0; padding: 11px 12px; border-radius: 10px; background: var(--surface); border: 1px solid var(--line); }
.network-basic-topology,
.client-server-topology { display: grid; grid-template-columns: minmax(120px, 1fr) auto minmax(150px, 1.1fr) auto minmax(150px, 1fr); gap: 10px; align-items: center; text-align: center; }
.network-hub { padding: 16px 12px; border-radius: 50%; background: var(--diagram-device-bg); color: var(--diagram-device-text); }
.network-hub strong, .network-hub small, .endpoint-stack { display: block; }
.network-hub small { margin-top: 4px; color: inherit; opacity: .85; }
.endpoint-stack { display: grid; gap: 8px; }
.topology-arrow { color: var(--primary-strong); font-size: 24px; font-weight: 800; }
.lan-wan-topology { display: grid; grid-template-columns: minmax(160px, 1fr) minmax(150px, .8fr) minmax(160px, 1fr); gap: 12px; align-items: stretch; }
.lan-site { display: grid; gap: 6px; align-content: center; padding: 16px; border: 2px solid var(--primary); border-radius: 14px; text-align: center; background: var(--surface); }
.lan-site small { color: var(--muted); }
.wan-link { display: grid; gap: 3px; align-content: center; text-align: center; color: var(--primary-strong); }
.wan-link span { font-weight: 850; }
.wan-link b { font-size: 28px; }
.wan-link small { color: var(--muted); }
.delivery-topology { display: grid; grid-template-columns: repeat(7, auto); gap: 8px; align-items: center; justify-content: center; }
.delivery-stage { min-width: 115px; padding: 12px 9px; border: 1px solid var(--line); border-radius: 12px; background: var(--surface); text-align: center; }
.delivery-stage strong, .delivery-stage small { display: block; }
.delivery-stage small { margin-top: 4px; color: var(--muted); }
.packet-chip { padding: 7px 9px; color: var(--primary-strong); border-radius: 9px; font-size: 13px; font-weight: 800; text-align: center; }
.packet-with-address { display: grid; gap: 2px; min-width: 116px; border: 1px dashed var(--primary); background: var(--primary-soft); }
.packet-with-address small,
.packet-with-address strong { display: block; }
.packet-with-address small { color: var(--muted); font-size: 10px; font-weight: 700; }
.packet-with-address strong { font-size: 12px; white-space: nowrap; }
.client-server-topology { grid-template-columns: minmax(145px, 1fr) minmax(180px, 1.2fr) minmax(145px, 1fr); }
.role-device { padding-block: 18px; }
.request-response { display: grid; gap: 9px; color: var(--primary-strong); font-weight: 800; }
.osi-diagram { max-width: 820px; margin-inline: auto; }
.osi-flow-edge {
  display: flex;
  gap: 10px;
  align-items: baseline;
  padding: 8px 12px;
  border-radius: 10px;
  background: color-mix(in srgb, var(--primary) 8%, var(--surface));
  font-size: 13px;
}
.osi-flow-edge strong { color: var(--primary-strong); }
.osi-flow-edge span { color: var(--muted); }
.top-edge { margin-bottom: 10px; }
.bottom-edge { margin-top: 10px; }
.osi-mapping { display: grid; gap: 8px; }
.osi-map-group {
  --layer-color: var(--primary);
  display: grid;
  grid-template-columns: minmax(150px, .75fr) 62px minmax(0, 1.45fr);
  gap: 10px;
  align-items: stretch;
  padding: 10px;
  border: 1px solid color-mix(in srgb, var(--layer-color) 45%, var(--line));
  border-left: 5px solid var(--layer-color);
  border-radius: 12px;
  background: color-mix(in srgb, var(--layer-color) 5%, var(--surface));
}
.application-group { --layer-color: #7c68c7; }
.transport-group { --layer-color: #25836e; }
.internet-group { --layer-color: #2675a8; }
.access-group { --layer-color: #aa6c21; }
.tcpip-layer-label {
  display: grid;
  align-content: center;
  gap: 3px;
  padding: 10px;
  border: 2px solid var(--layer-color);
  border-radius: 10px;
  background: var(--surface);
}
.tcpip-layer-label small,
.osi-layer-list > small { color: var(--muted); font-size: 11px; font-weight: 750; }
.tcpip-layer-label strong { color: var(--text); }
.tcpip-layer-label span { color: var(--muted); font-size: 12px; }
.mapping-label {
  display: grid;
  place-items: center;
  color: var(--layer-color);
  font-size: 12px;
  font-weight: 800;
  text-align: center;
}
.mapping-label::after { content: "→"; display: block; font-size: 20px; line-height: 1; }
.osi-layer-list { display: grid; min-width: 0; gap: 5px; }
.osi-layer-list > div {
  display: grid;
  grid-template-columns: minmax(0, .95fr) minmax(0, 1.05fr);
  gap: 8px;
  align-items: center;
  min-width: 0;
  padding: 7px 9px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
}
.osi-layer-list b { min-width: 0; font-size: 13px; overflow-wrap: anywhere; }
.osi-layer-list span { min-width: 0; color: var(--muted); font-size: 12px; overflow-wrap: anywhere; }
.component-map,
.ap-firewall-map { display: grid; grid-template-columns: repeat(7, auto); gap: 8px; align-items: center; justify-content: center; }
.component-group { display: grid; gap: 6px; min-width: 125px; padding: 12px; border: 1px solid var(--line); border-radius: 12px; background: var(--surface); text-align: center; }
.component-group strong { color: var(--primary-strong); }
.component-group span { font-size: 13px; }
.secure-group { border-color: var(--accent); }
.component-arrow { color: var(--primary-strong); font-size: 23px; font-weight: 850; text-align: center; }
.switch-role-map { display: grid; grid-template-columns: minmax(150px, .8fr) auto minmax(240px, 1.25fr) minmax(185px, 1fr); gap: 12px; align-items: center; }
.router-role-map { display: grid; grid-template-columns: minmax(125px, 1fr) auto minmax(150px, 1fr) minmax(155px, 1fr); gap: 10px; align-items: center; }
.switch-source,
.switch-routing-box,
.destination-card {
  display: grid;
  gap: 5px;
  padding: 12px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--surface);
}
.switch-source { text-align: center; }
.switch-source strong,
.switch-routing-box > strong,
.destination-card strong { color: var(--primary-strong); }
.switch-source small,
.switch-routing-box > small,
.destination-card small { color: var(--muted); }
.connection-label {
  margin-top: 5px;
  padding-top: 5px;
  border-top: 2px solid var(--primary);
  color: var(--muted);
  font-size: 12px;
}
.switch-routing-box {
  border: 2px solid var(--primary);
  box-shadow: inset 0 0 0 3px color-mix(in srgb, var(--primary) 8%, transparent);
}
.switch-port-route {
  display: grid;
  grid-template-columns: 76px 1fr;
  gap: 8px;
  align-items: center;
  padding: 8px 9px;
  border: 1px solid var(--line);
  border-radius: 8px;
  font-size: 13px;
}
.switch-port-route b { color: var(--text); }
.receive-route { border-left: 4px solid var(--accent); }
.forward-route { border-left: 4px solid var(--success); background: var(--success-soft); }
.blocked-route { border-left: 4px solid var(--line); color: var(--muted); }
.switch-destinations { display: grid; gap: 10px; }
.destination-card.active-target { border: 2px solid var(--success); }
.destination-card.inactive-target { border-style: dashed; }
.vlan-learning-diagram { max-width: 850px; margin-inline: auto; }
.access-port-map { display: grid; gap: 10px; }
.vlan-lane {
  --vlan-color: var(--primary);
  display: grid;
  grid-template-columns: minmax(150px, .8fr) 105px minmax(210px, 1fr);
  gap: 10px;
  align-items: center;
  padding: 11px;
  border: 1px solid color-mix(in srgb, var(--vlan-color) 55%, var(--line));
  border-left: 6px solid var(--vlan-color);
  border-radius: 12px;
  background: color-mix(in srgb, var(--vlan-color) 7%, var(--surface));
}
.vlan-10 { --vlan-color: #2887b8; }
.vlan-20 { --vlan-color: #b67525; }
.endpoint-card, .port-card, .trunk-switch {
  display: grid;
  gap: 4px;
  padding: 10px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--surface);
}
.endpoint-card small, .port-card small, .trunk-switch small { color: var(--muted); }
.port-card { border: 2px solid var(--vlan-color); }
.port-card b { color: var(--vlan-color); font-size: 13px; }
.labeled-arrow { display: grid; justify-items: center; color: var(--muted); font-size: 11px; }
.labeled-arrow b { color: var(--vlan-color); font-size: 24px; line-height: 1; }
.trunk-map { display: grid; grid-template-columns: minmax(180px, 1fr) minmax(210px, 1.15fr) minmax(180px, 1fr); gap: 12px; align-items: center; }
.trunk-switch { text-align: center; }
.vlan-chip, .tag-chip { padding: 6px 8px; border: 2px solid var(--vlan-color); border-radius: 8px; background: color-mix(in srgb, var(--vlan-color) 10%, var(--surface)); font-size: 13px; font-weight: 800; }
.trunk-link { display: grid; gap: 7px; justify-items: center; padding: 10px; border-top: 4px double var(--primary); border-bottom: 4px double var(--primary); text-align: center; }
.trunk-link > div { display: flex; gap: 6px; flex-wrap: wrap; justify-content: center; }
.trunk-link > b { color: var(--primary-strong); font-size: 22px; }
.trunk-link small { color: var(--muted); }
.native-vlan-map { display: grid; gap: 7px; }
.native-flow {
  display: grid;
  grid-template-columns: minmax(150px, .75fr) minmax(110px, .65fr) 40px minmax(180px, 1fr);
  gap: 9px;
  align-items: center;
  padding: 9px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--surface);
}
.native-flow > b { text-align: center; }
.native-flow > span[aria-hidden] { color: var(--primary-strong); font-size: 22px; text-align: center; }
.native-flow-highlight { border: 2px solid var(--accent); background: color-mix(in srgb, var(--accent) 8%, var(--surface)); }
.native-chip { --vlan-color: var(--accent); }
.native-warning { display: grid; gap: 3px; margin-top: 10px; padding: 10px 12px; border-left: 5px solid var(--danger); border-radius: 9px; background: var(--danger-soft); }
.native-warning span { font-size: 13px; }
.source-group { min-width: 0; }
.split-targets, .route-choice { display: grid; gap: 8px; }
.split-targets span, .route-choice span { padding: 9px; border-radius: 9px; background: var(--surface); border: 1px solid var(--line); font-size: 13px; }
.active-target, .right-route, .permit { color: var(--success); font-weight: 800; }
.inactive-target, .wrong-route { color: var(--muted); }
.router-role-map { grid-template-columns: minmax(135px, 1fr) auto minmax(145px, 1fr) minmax(160px, 1fr) minmax(135px, 1fr); }
.wireless-link { display: grid; gap: 2px; color: var(--primary-strong); font-weight: 850; text-align: center; }
.deny { color: var(--danger); font-weight: 800; }
.virtualization-map { display: grid; grid-template-columns: repeat(2, minmax(190px, 1fr)); gap: 14px; align-items: start; }
.virtual-column { min-width: 0; }
.virtual-kind { display: block; margin-bottom: 7px; color: var(--primary-strong); text-align: center; }
.duplex-map { display: grid; grid-template-columns: minmax(190px, 1fr) auto minmax(190px, 1fr); gap: 14px; align-items: center; }
.virtual-stack { display: grid; grid-template-columns: 1fr 1fr; gap: 6px; padding: 12px; border: 1px solid var(--line); border-radius: 12px; background: var(--surface); text-align: center; }
.virtual-stack b, .virtual-stack small { grid-column: 1 / -1; }
.virtual-stack span, .virtual-stack b, .virtual-stack small { padding: 7px; border-radius: 7px; border: 1px solid var(--line); }
.virtual-stack b { background: color-mix(in srgb, var(--primary) 16%, var(--surface)); }
.container-stack span { border-color: var(--accent); }
.cable-map { display: grid; grid-template-columns: auto 1fr auto 1.2fr auto; gap: 9px; align-items: center; }
.cable { padding: 10px; text-align: center; font-weight: 800; }
.cable small { display: block; color: var(--muted); font-weight: 500; }
.copper-link { border-top: 4px double var(--primary); }
.fiber-link { border-top: 4px solid var(--accent); }
.poe-map { display: grid; grid-template-columns: minmax(180px, .8fr) minmax(240px, 1.2fr); gap: 16px; align-items: center; }
.poe-targets { display: grid; gap: 10px; }
.poe-targets span { padding: 11px; border: 1px solid var(--line); border-radius: 10px; background: var(--surface); font-weight: 750; }
.poe-targets b { display: block; color: var(--primary-strong); }
.poe-targets small { display: block; margin-top: 3px; color: var(--muted); font-weight: 500; }
.duplex-map { grid-template-columns: 1fr 1fr; }
.duplex-example { display: grid; gap: 7px; padding: 14px; border: 2px solid var(--primary); border-radius: 12px; background: var(--surface); text-align: center; }
.duplex-example small { color: var(--muted); }
.half-duplex { border-color: var(--accent); }
.troubleshooting-flow { display: grid; grid-template-columns: repeat(5, 1fr); gap: 8px; margin: 0; padding: 0; list-style: none; }
.troubleshooting-flow li { display: grid; gap: 6px; align-content: center; min-height: 82px; padding: 10px; border: 1px solid var(--line); border-radius: 10px; background: var(--surface); text-align: center; font-size: 13px; }
.troubleshooting-flow strong { color: var(--primary-strong); font-size: 20px; }
.ip-check-flow { display: grid; gap: 10px; margin: 0; padding: 0; list-style: none; }
.ip-check-flow li { display: grid; grid-template-columns: 36px minmax(0, 1fr); gap: 12px; align-items: start; padding: 12px; border: 1px solid var(--line); border-radius: 12px; background: var(--surface); }
.ip-check-flow li > b { display: grid; place-items: center; width: 32px; height: 32px; border-radius: 50%; background: var(--primary-soft); color: var(--primary-strong); }
.ip-check-flow li > div { display: grid; gap: 4px; min-width: 0; }
.ip-check-flow strong { color: var(--text); }
.ip-check-flow span { color: var(--primary-strong); font-weight: 700; }
.ip-check-flow small { color: var(--muted); line-height: 1.6; }
.encapsulation-map { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; justify-content: center; }
.encapsulation-map span { padding: 12px 15px; border: 2px solid var(--primary); border-radius: 11px; background: var(--surface); font-weight: 800; }
.encapsulation-map b { color: var(--primary-strong); }
.encapsulation-journey { display: grid; grid-template-columns: minmax(220px, 1fr) 120px minmax(220px, 1fr); gap: 14px; align-items: center; }
.encapsulation-side { display: grid; gap: 7px; min-width: 0; }
.encapsulation-side h4 { margin: 0 0 3px; color: var(--primary-strong); text-align: center; }
.protocol-unit { display: grid; grid-template-columns: auto 1fr; gap: 6px; align-items: center; padding: 10px; border: 2px solid var(--line); border-radius: 11px; background: var(--surface); }
.protocol-unit > small, .protocol-unit > b { grid-column: 1 / -1; }
.protocol-unit > small { color: var(--muted); font-weight: 750; }
.protocol-unit > b { color: var(--muted); font-size: 11px; font-weight: 600; }
.app-unit { grid-template-columns: 1fr; border-color: var(--accent); text-align: center; }
.packet-unit { border-color: var(--primary); }
.frame-unit { grid-template-columns: auto 1fr; border-color: var(--accent); }
.header-chip { padding: 6px 7px; border-radius: 7px; color: #102126; font-size: 11px; font-weight: 850; text-align: center; }
.ip-chip { background: #8ed9ff; }
.mac-chip { background: #f6c56e; }
.nested-packet { display: grid; grid-template-columns: auto 1fr; gap: 5px; padding: 6px; border: 2px solid var(--primary); border-radius: 8px; background: color-mix(in srgb, var(--primary) 8%, var(--surface)); }
.nested-packet span { padding: 4px 6px; border-radius: 5px; background: #8ed9ff; color: #102126; font-size: 10px; font-weight: 850; }
.nested-packet strong { align-self: center; font-size: 11px; }
.encapsulation-action { color: var(--muted); font-size: 12px; font-weight: 750; text-align: center; }
.encapsulation-transit { display: grid; gap: 5px; color: var(--primary-strong); text-align: center; }
.encapsulation-transit b { font-size: 26px; }
.encapsulation-transit small { color: var(--muted); }
.mac-flow,
.mac-learning-map,
.arp-flow,
.ping-flow,
.tcpudp-map { display: grid; grid-template-columns: minmax(145px, 1fr) auto minmax(170px, 1fr) auto minmax(145px, 1fr); gap: 10px; align-items: center; }
.mac-learning-map { grid-template-columns: minmax(135px, .65fr) auto minmax(330px, 1.7fr); }
.mac-source b { color: var(--primary-strong); }
.mac-switch-chassis { min-width: 0; padding: 14px; border: 2px solid var(--primary); border-radius: 15px; background: var(--diagram-device-bg); color: var(--diagram-device-text); }
.mac-switch-title { display: flex; align-items: baseline; justify-content: space-between; gap: 10px; }
.mac-switch-title span { font-size: 12px; opacity: .8; }
.mac-port-strip { display: grid; grid-template-columns: repeat(3, 1fr); gap: 6px; margin-top: 11px; }
.mac-port-strip span { min-height: 36px; display: grid; place-items: center; padding: 5px; border: 1px solid #61737b; border-radius: 7px; color: var(--diagram-device-text); font-size: 12px; }
.mac-port-strip span.is-active { border-color: var(--primary); background: color-mix(in srgb, var(--primary) 22%, var(--diagram-device-bg)); }
.mac-port-strip small { display: block; font-size: 9px; color: var(--primary); font-weight: 800; }
.mac-learn-action { display: grid; justify-items: center; gap: 2px; padding: 7px 0; color: var(--diagram-device-text); text-align: center; font-size: 12px; }
.mac-learn-action span { color: var(--primary); font-size: 18px; line-height: 1; }
.mac-table-panel { padding: 10px; border: 1px solid #52666f; border-radius: 10px; background: #1f3037; }
:root[data-theme="light"] .mac-table-panel { background: #e8f0f2; color: #263238; }
.mac-table-panel > strong { display: block; margin-bottom: 8px; text-align: center; font-size: 12px; }
.mac-table-grid { display: grid; grid-template-columns: .55fr 1.2fr .85fr; overflow: hidden; border: 1px solid #61737b; border-radius: 7px; }
.mac-table-grid > * { padding: 7px 5px; border-right: 1px solid #61737b; text-align: center; font-size: 11px; }
.mac-table-grid > :nth-child(3n) { border-right: 0; }
.mac-table-grid > b { background: color-mix(in srgb, var(--primary) 18%, #1f3037); color: var(--diagram-device-text); }
:root[data-theme="light"] .mac-table-grid > b { background: var(--primary-soft); color: var(--text); }
.mac-table-grid > span { border-top: 1px solid #61737b; }
.labeled-flow-arrow { display: grid; gap: 2px; justify-items: center; color: var(--muted); font-size: 11px; text-align: center; }
.labeled-flow-arrow b { color: var(--primary-strong); font-size: 13px; }
.forwarding-board { display: grid; grid-template-columns: 130px minmax(0, 1fr); gap: 10px; align-items: stretch; }
.forwarding-source { display: grid; align-content: center; justify-items: center; gap: 5px; padding: 14px; border: 2px solid var(--primary); border-radius: 12px; background: var(--surface); text-align: center; }
.forwarding-source::after { content: "→"; color: var(--primary-strong); font-size: 24px; font-weight: 900; }
.forwarding-source span { color: var(--muted); font-size: 12px; }
.forwarding-cases { display: grid; gap: 8px; }
.forwarding-case { display: grid; grid-template-columns: minmax(120px, .8fr) minmax(145px, 1fr) minmax(150px, 1fr); gap: 8px; align-items: center; padding: 10px; border: 1px solid var(--line); border-radius: 11px; background: var(--surface); }
.forwarding-label, .forwarding-decision { display: grid; gap: 3px; }
.forwarding-label span, .forwarding-decision small { color: var(--muted); font-size: 11px; }
.forwarding-decision { padding: 7px; border-radius: 8px; background: var(--surface-soft); text-align: center; }
.forwarding-decision b { color: var(--primary-strong); font-size: 12px; }
.forwarding-ports { display: grid; grid-template-columns: repeat(3, 1fr); gap: 5px; }
.forwarding-ports span { padding: 6px 3px; border: 1px solid var(--line); border-radius: 7px; text-align: center; font-weight: 800; font-size: 12px; }
.forwarding-ports small { color: var(--muted); font-size: 9px; font-weight: 600; }
.forwarding-ports .is-in { border-color: var(--accent); }
.forwarding-ports .is-out, .forwarding-ports .is-flood { border-color: var(--primary); background: color-mix(in srgb, var(--primary) 16%, var(--surface)); }
.arp-exchange { display: grid; gap: 10px; }
.arp-step { padding: 11px; border: 1px solid var(--line); border-radius: 12px; background: var(--surface); }
.arp-step-title { display: flex; align-items: center; gap: 9px; margin-bottom: 10px; }
.arp-step-title > b { width: 29px; height: 29px; display: grid; place-items: center; flex: 0 0 auto; border-radius: 50%; background: var(--primary-soft); color: var(--primary-strong); }
.arp-step-title > span { display: grid; }
.arp-step-title small { color: var(--muted); }
.arp-network { display: grid; grid-template-columns: minmax(155px, .8fr) minmax(150px, .75fr) minmax(220px, 1.2fr); gap: 18px; align-items: center; }
.arp-network > * { position: relative; }
.arp-network > :not(:last-child)::after { content: "→"; position: absolute; top: 50%; right: -15px; transform: translateY(-50%); color: var(--primary-strong); font-size: 19px; font-weight: 900; }
.arp-network.response { direction: rtl; }
.arp-network.response > * { direction: ltr; }
.arp-network.response > :not(:last-child)::after { content: "←"; right: auto; left: -15px; }
.arp-device, .arp-switch { display: grid; gap: 4px; padding: 10px; border: 1px solid var(--line); border-radius: 9px; text-align: center; }
.arp-device small, .arp-switch small, .arp-receivers small { color: var(--muted); }
.arp-device em { font-size: 11px; color: var(--primary-strong); font-style: normal; font-weight: 700; }
.arp-switch { background: var(--diagram-device-bg); color: var(--diagram-device-text); }
.arp-switch small { color: inherit; opacity: .78; }
.arp-receivers { display: grid; grid-template-columns: repeat(2, 1fr); gap: 6px; }
.arp-receivers span { display: grid; gap: 3px; padding: 8px; border: 1px solid var(--line); border-radius: 8px; text-align: center; }
.arp-receivers span.is-owner { border-color: var(--primary); background: color-mix(in srgb, var(--primary) 13%, var(--surface)); }
.arp-receivers span.is-muted { opacity: .58; }
.arp-receivers b { font-size: 10px; color: var(--primary-strong); }
.ping-exchange { display: grid; gap: 10px; }
.ping-trip { display: grid; grid-template-columns: minmax(170px, .65fr) minmax(0, 1.8fr); gap: 10px; align-items: center; padding: 10px; border: 1px solid var(--line); border-radius: 12px; background: var(--surface); }
.ping-trip-label { display: flex; align-items: center; gap: 8px; }
.ping-trip-label > b { width: 29px; height: 29px; display: grid; place-items: center; flex: 0 0 auto; border-radius: 50%; background: var(--primary-soft); color: var(--primary-strong); }
.ping-trip-label > span { display: grid; }
.ping-trip-label small { color: var(--muted); }
.ping-route { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 22px; }
.ping-hop { position: relative; display: grid; gap: 3px; align-content: center; min-height: 58px; padding: 8px; border: 1px solid var(--line); border-radius: 9px; text-align: center; }
.ping-hop small { color: var(--muted); }
.ping-hop.network { background: var(--diagram-device-bg); color: var(--diagram-device-text); }
.ping-hop.network small { color: inherit; opacity: .78; }
.ping-hop:not(:last-child)::after { content: "→"; position: absolute; top: 50%; right: -18px; transform: translateY(-50%); color: var(--primary-strong); font-size: 18px; font-weight: 900; }
.ping-reading { display: grid; grid-template-columns: repeat(2, 1fr); gap: 8px; }
.ping-reading > div { display: grid; gap: 3px; padding: 10px; border-radius: 9px; border: 1px solid var(--line); }
.ping-reading .success { border-color: var(--success); background: var(--success-soft); }
.ping-reading .failure { border-color: var(--accent); background: color-mix(in srgb, var(--accent) 10%, var(--surface)); }
.ping-reading span { font-size: 12px; color: var(--muted); }
.arp-flow, .ping-flow { grid-template-columns: minmax(150px, 1fr) minmax(220px, 1.4fr) minmax(150px, 1fr); }
.transport-addressing { display: grid; grid-template-columns: minmax(120px, .7fr) minmax(135px, .8fr) minmax(145px, .85fr) minmax(190px, 1.15fr); gap: 20px; align-items: center; }
.transport-addressing > * { position: relative; }
.transport-addressing > :not(:last-child)::after { content: "→"; position: absolute; top: 50%; right: -17px; transform: translateY(-50%); color: var(--primary-strong); font-size: 19px; font-weight: 900; }
.transport-client, .address-selector, .port-selector { display: grid; gap: 4px; min-height: 76px; align-content: center; padding: 10px; border: 1px solid var(--line); border-radius: 10px; background: var(--surface); text-align: center; }
.transport-addressing small { color: var(--muted); }
.address-selector { border-color: var(--primary); }
.port-selector { border-color: var(--accent); }
.transport-server { display: grid; gap: 4px; padding: 11px; border-radius: 11px; background: var(--diagram-device-bg); color: var(--diagram-device-text); text-align: center; }
.transport-server > small { color: inherit; opacity: .78; }
.transport-server > div { display: grid; gap: 5px; margin-top: 5px; }
.transport-server span { display: grid; grid-template-columns: 65px 1fr; padding: 6px; border: 1px solid #596d75; border-radius: 7px; color: var(--diagram-device-text); font-size: 11px; }
.transport-server span.is-selected { border-color: var(--accent); background: color-mix(in srgb, var(--accent) 18%, var(--diagram-device-bg)); }
.transport-compare { display: grid; grid-template-columns: repeat(2, 1fr); gap: 10px; margin-top: 12px; }
.transport-compare section { padding: 12px; border: 1px solid var(--line); border-radius: 11px; background: var(--surface); }
.transport-compare header { display: flex; align-items: baseline; justify-content: space-between; gap: 10px; padding-bottom: 7px; border-bottom: 1px solid var(--line); }
.transport-compare header strong { color: var(--primary-strong); font-size: 18px; }
.transport-compare header span { color: var(--muted); font-size: 12px; }
.transport-compare ol { display: grid; grid-template-columns: repeat(4, 1fr); gap: 5px; margin: 10px 0; padding: 0; list-style: none; counter-reset: transport-step; }
.transport-compare li { display: grid; gap: 4px; align-content: start; padding: 7px; border-radius: 8px; background: var(--surface-soft); font-size: 11px; text-align: center; counter-increment: transport-step; }
.transport-compare li::before { content: counter(transport-step); width: 20px; height: 20px; display: grid; place-items: center; margin: 0 auto; border-radius: 50%; background: var(--primary-soft); color: var(--primary-strong); font-weight: 800; }

@media (min-width: 721px) {
  .grid-align .progress-card .progress-detail {
    gap: 8px;
    align-items: stretch;
  }
  .grid-align .progress-card [data-progress-count] {
    flex: 0 0 100%;
  }
  .grid-align .progress-card .progress-detail .button {
    flex: 1 1 0;
    min-width: 0;
    min-height: 40px;
    padding: 8px 10px;
    font-size: 13px;
    text-align: center;
  }
  .topology-arrow,
  .component-arrow,
  .wan-link b,
  .labeled-arrow b,
  .trunk-link > b,
  .native-flow > span[aria-hidden],
  .mapping-label::after,
  .forwarding-source::after,
  .labeled-flow-arrow b {
    color: var(--diagram-arrow);
    font-size: 28px;
    font-weight: 900;
    line-height: 1;
    text-shadow: 0 1px 0 var(--surface), 0 0 5px color-mix(in srgb, var(--diagram-arrow) 32%, transparent);
  }

  .ip-delivery-map > :not(:last-child)::after,
  .arp-network > :not(:last-child)::after,
  .ping-hop:not(:last-child)::after,
  .transport-addressing > :not(:last-child)::after {
    color: var(--diagram-arrow);
    font-size: 25px;
    font-weight: 950;
    text-shadow: 0 1px 0 var(--surface), 0 0 5px color-mix(in srgb, var(--diagram-arrow) 32%, transparent);
  }
}
.transport-compare section > p { margin: 0; color: var(--muted); font-size: 11px; }
.tcpudp-map { grid-template-columns: minmax(145px, 1fr) minmax(190px, 1.2fr) minmax(160px, 1fr); }
.service-stack { display: grid; gap: 7px; padding: 13px; border-radius: 11px; background: var(--diagram-device-bg); color: var(--diagram-device-text); text-align: center; }
.service-stack span { padding: 7px; border-radius: 7px; background: var(--surface); color: var(--text); }
.concept-map-diagram { display: grid; gap: 12px; }
.concept-caption { margin-bottom: 0; color: var(--text); font-size: 14px; }
.concept-visual,
.concept-topology ul,
.concept-protection ul { margin: 0; padding: 0; list-style: none; }
.concept-visual li { position: relative; min-width: 0; }
.concept-visual li span,
.concept-topology li span,
.concept-protection li span { min-width: 0; }

.concept-process { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 24px; }
.concept-process li { display: grid; align-content: start; gap: 8px; padding: 13px; border: 1px solid var(--line); border-radius: 11px; background: var(--surface); }
.concept-process li > b { display: grid; place-items: center; width: 28px; height: 28px; border-radius: 50%; background: var(--primary); color: var(--surface); }
.concept-process li:not(:last-child)::after { content: "→"; position: absolute; top: 50%; right: -19px; color: var(--diagram-arrow); font-size: 20px; font-weight: 900; transform: translateY(-50%); }

.concept-exchange { display: grid; gap: 9px; }
.exchange-endpoints { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 42px; text-align: center; }
.exchange-endpoints strong { padding: 10px; border: 2px solid var(--primary); border-radius: 11px; background: var(--primary-soft); }
.concept-exchange ol { display: grid; gap: 8px; margin: 0; padding: 0; list-style: none; }
.concept-exchange li { display: grid; grid-template-columns: auto minmax(0, 1fr) 52px; gap: 9px; align-items: center; width: calc(50% + 21px); min-height: 62px; padding: 10px 12px; border: 1px solid var(--line); border-radius: 10px; background: var(--surface); }
.concept-exchange li.to-server { justify-self: start; }
.concept-exchange li.to-client { justify-self: end; grid-template-columns: 52px auto minmax(0, 1fr); }
.concept-exchange li > b { display: grid; place-items: center; width: 26px; height: 26px; border-radius: 50%; background: var(--primary); color: var(--surface); }
.concept-exchange li > i { color: var(--diagram-arrow); font-size: 24px; font-style: normal; font-weight: 900; text-align: center; }
.concept-exchange li.to-client > i { grid-column: 1; grid-row: 1; }
.concept-exchange li.to-client > b { grid-column: 2; grid-row: 1; }
.concept-exchange li.to-client > span { grid-column: 3; grid-row: 1; }

.concept-layers { display: grid; gap: 7px; width: min(600px, 100%); margin-inline: auto; }
.concept-layers li { display: grid; grid-template-columns: 90px 1fr; gap: 10px; align-items: center; padding: 11px 14px; border: 1px solid var(--line); border-left: 5px solid var(--primary); border-radius: 8px; background: var(--surface); }
.concept-layers li > b { color: var(--primary-strong); font-size: 11px; }
.concept-layers li:not(:last-child)::after { content: "↓"; position: absolute; z-index: 1; right: 16px; bottom: -15px; color: var(--diagram-arrow); font-weight: 900; }

.concept-decision { display: grid; gap: 8px; justify-items: center; }
.concept-decision li { display: grid; grid-template-columns: 76px minmax(0, 1fr); gap: 10px; align-items: center; width: calc(100% - (var(--decision-step, 0) * 7%)); max-width: 680px; padding: 11px 14px; border: 1px solid var(--line); border-radius: 10px; background: var(--surface); }
.concept-decision li:nth-child(1) { --decision-step: 0; }
.concept-decision li:nth-child(2) { --decision-step: 1; }
.concept-decision li:nth-child(3) { --decision-step: 2; }
.concept-decision li:nth-child(4) { --decision-step: 3; }
.concept-decision li > b { padding: 4px 7px; border-radius: 999px; background: var(--primary-soft); color: var(--primary-strong); font-size: 11px; text-align: center; }
.concept-decision li:not(:last-child)::after { content: "↓"; position: absolute; bottom: -15px; left: 50%; z-index: 1; color: var(--diagram-arrow); font-weight: 900; }

.concept-checklist { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 9px; }
.concept-checklist li { display: grid; grid-template-columns: auto 1fr; gap: 10px; align-items: start; padding: 12px; border: 1px solid var(--line); border-radius: 10px; background: var(--surface); }
.concept-checklist li > b { display: grid; place-items: center; width: 25px; height: 25px; border-radius: 7px; background: var(--primary-soft); color: var(--primary-strong); }

.concept-compare { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 9px; }
.concept-compare li { display: grid; grid-template-columns: auto 1fr; gap: 10px; align-items: start; padding: 13px; border: 1px solid var(--line); border-radius: 11px; background: var(--surface); }
.concept-compare li > b { min-width: 74px; padding: 5px 7px; border-radius: 999px; font-size: 11px; text-align: center; }
.concept-compare li:nth-child(odd) > b { background: var(--primary-soft); color: var(--primary-strong); }
.concept-compare li:nth-child(even) > b { background: color-mix(in srgb, var(--accent) 18%, var(--surface)); color: var(--text); }

.concept-topology { display: grid; grid-template-columns: minmax(140px, .7fr) minmax(0, 1.6fr); gap: 22px; align-items: center; }
.topology-center { display: grid; justify-items: center; gap: 6px; padding: 20px 12px; border: 2px solid var(--primary); border-radius: 50%; background: var(--primary-soft); text-align: center; }
.topology-center > span { color: var(--primary-strong); font-size: 25px; }
.concept-topology ul { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 10px; }
.concept-topology li { position: relative; display: grid; grid-template-columns: auto 1fr; gap: 8px; padding: 12px; border: 1px solid var(--line); border-radius: 10px; background: var(--surface); }
.concept-topology li > b { color: var(--primary-strong); }
.concept-topology li::before { content: ""; position: absolute; top: 50%; left: -23px; width: 22px; border-top: 2px solid var(--diagram-arrow); opacity: .75; }

.concept-protection { display: grid; grid-template-columns: minmax(150px, .75fr) minmax(0, 1.6fr); gap: 20px; align-items: center; }
.protection-core { display: grid; justify-items: center; gap: 5px; padding: 20px 12px; border: 2px solid var(--primary); border-radius: 45% 45% 50% 50%; background: var(--primary-soft); text-align: center; }
.protection-core > span { color: var(--primary-strong); font-size: 28px; }
.protection-core small { color: var(--muted); }
.concept-protection ul { display: grid; gap: 8px; }
.concept-protection li { display: grid; grid-template-columns: auto 1fr; gap: 9px; padding: 11px 12px; border: 1px solid var(--line); border-left: 4px solid var(--primary); border-radius: 9px; background: var(--surface); }
.concept-protection li > b { color: var(--primary-strong); }
.complex-svg-diagram { overflow: hidden; }
.learning-svg { display: block; width: min(100%, 500px); height: auto; margin-inline: auto; }
.svg-node { fill: var(--surface); stroke: var(--line); stroke-width: 2; }
.svg-node.primary { fill: var(--primary-soft); stroke: var(--primary); }
.svg-node.private { fill: color-mix(in srgb, var(--primary) 10%, var(--surface)); stroke: color-mix(in srgb, var(--primary) 68%, var(--line)); }
.svg-node.network { fill: var(--diagram-device-bg); stroke: var(--primary); }
.svg-node.network + .svg-node-title,
.svg-node.network ~ .svg-node-copy { fill: var(--diagram-device-text); }
.svg-node.destination { fill: color-mix(in srgb, var(--accent) 13%, var(--surface)); stroke: var(--accent); }
.svg-node.warning { fill: color-mix(in srgb, var(--danger) 12%, var(--surface)); stroke: var(--danger); }
.svg-node-title, .svg-note-title { fill: var(--text); font-size: 17px; font-weight: 800; }
.svg-node-copy { fill: var(--muted); font-size: 14px; }
.svg-link { stroke: var(--diagram-arrow); stroke-width: 3; }
.svg-arrow-head { fill: var(--diagram-arrow); }
.svg-link-label { fill: var(--primary-strong); font-size: 13px; font-weight: 750; paint-order: stroke; stroke: var(--surface-soft); stroke-width: 5px; stroke-linejoin: round; }
.svg-note-box { fill: color-mix(in srgb, var(--primary) 7%, var(--surface)); stroke: var(--line); stroke-width: 2; }
.svg-return-link, .svg-failover-link, .svg-branch-link { fill: none; stroke: var(--diagram-arrow); stroke-width: 3; stroke-dasharray: 7 5; marker-end: var(--svg-marker); }
.svg-parallel-links line { stroke: var(--diagram-arrow); stroke-width: 5; }
.svg-channel-bracket { fill: none; stroke: var(--primary); stroke-width: 2; stroke-dasharray: 7 5; }
.svg-failed-link, .svg-path-blocked { stroke: var(--danger); stroke-width: 4; }
.svg-warning-text { fill: var(--danger); font-size: 13px; font-weight: 800; }
.svg-path-active, .svg-standby-link { stroke: var(--diagram-arrow); stroke-width: 4; fill: none; }
.svg-standby-link { stroke-dasharray: 7 5; }
.svg-wifi-wave { fill: none; stroke: var(--primary); stroke-width: 7; stroke-linecap: round; opacity: .85; }
.svg-block-badge { fill: color-mix(in srgb, var(--danger) 18%, var(--surface)); stroke: var(--danger); }
.svg-block-text { fill: var(--text); font-size: 13px; font-weight: 800; }
.svg-lan-segment, .svg-virtual-ip { fill: var(--diagram-device-bg); stroke: var(--primary); stroke-width: 2; }
.svg-lan-segment + .svg-node-title,
.svg-virtual-ip + .svg-node-title { fill: var(--diagram-device-text); }
.svg-tunnel, .svg-tunnel-inner { fill: none; stroke: var(--primary); stroke-width: 5; stroke-dasharray: 10 6; }
.svg-branch-link.blocked { stroke: var(--danger); }
.binary-place-grid { display: grid; grid-template-columns: repeat(8, minmax(58px, 1fr)); gap: 6px; }
.binary-place { display: grid; gap: 4px; justify-items: center; padding: 9px 4px; border: 1px solid var(--line); border-radius: 9px; background: var(--surface); text-align: center; }
.binary-place small, .binary-place b { color: var(--muted); font-size: 10px; }
.binary-place strong { font-size: 12px; }
.binary-place span { display: grid; place-items: center; width: 31px; height: 31px; border-radius: 8px; background: var(--surface-soft); font-size: 18px; font-weight: 850; }
.binary-place.is-on { border-color: var(--primary); background: color-mix(in srgb, var(--primary) 9%, var(--surface)); }
.binary-place.is-on span { background: var(--primary); color: var(--surface); }
.binary-place.is-on b { color: var(--primary-strong); }
.binary-calculation { display: grid; gap: 5px; justify-items: center; margin-top: 12px; padding: 12px; border: 1px solid var(--line); border-radius: 10px; background: var(--surface-soft); text-align: center; }
.binary-calculation span { color: var(--muted); font-size: 12px; }
.binary-calculation strong { font-size: 18px; }
.binary-calculation b { color: var(--primary-strong); }
.binary-reverse { margin-top: 18px; padding-top: 16px; border-top: 1px solid var(--line); }
.binary-reverse ol { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 7px; margin: 0; padding: 0; list-style: none; }
.binary-reverse li { display: grid; gap: 4px; padding: 9px; border: 1px solid var(--line); border-radius: 9px; background: var(--surface); text-align: center; }
.binary-reverse li b { color: var(--primary-strong); }
.binary-reverse li span { color: var(--muted); font-size: 11px; }
.host-address-row { display: grid; grid-template-columns: minmax(0, 2fr) auto minmax(130px, .75fr); gap: 12px; align-items: stretch; }
.host-network-side, .host-device-side { display: grid; gap: 8px; align-content: center; padding: 14px; border: 2px solid var(--primary); border-radius: 12px; background: var(--surface); text-align: center; }
.host-network-side > div { display: grid; grid-template-columns: repeat(3, 1fr); gap: 6px; }
.host-network-side span, .host-device-side strong { padding: 9px 5px; border-radius: 8px; background: var(--primary-soft); color: var(--primary-strong); font-size: 18px; font-weight: 850; }
.host-network-side small, .host-device-side small { color: var(--muted); }
.host-network-side b, .host-device-side b { font-size: 11px; }
.host-device-side { border-color: var(--accent); }
.host-device-side strong { background: color-mix(in srgb, var(--accent) 15%, var(--surface)); color: var(--text); }
.host-boundary { display: grid; grid-template-rows: auto 1fr; justify-items: center; gap: 6px; color: var(--accent); font-size: 11px; text-align: center; }
.host-boundary span { width: 3px; height: 100%; border-radius: 99px; background: var(--accent); }
.cidr-octets { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 7px; }
.cidr-octets > div { display: grid; gap: 5px; justify-items: center; padding: 11px 5px; border: 1px solid var(--primary); border-radius: 9px; background: color-mix(in srgb, var(--primary) 8%, var(--surface)); }
.cidr-octets > div.is-host { border-color: var(--accent); background: color-mix(in srgb, var(--accent) 8%, var(--surface)); }
.cidr-octets strong { font-size: 18px; }
.cidr-octets span { font-family: ui-monospace, SFMono-Regular, Consolas, monospace; font-size: 12px; overflow-wrap: anywhere; }
.cidr-octets b { color: var(--muted); font-size: 10px; }
.cidr-calculation { display: grid; gap: 5px; justify-items: center; margin-top: 12px; padding: 12px; border-radius: 10px; background: var(--surface-soft); text-align: center; }
.cidr-calculation span { color: var(--muted); font-size: 11px; }
.cidr-calculation strong { font-size: 18px; }
.cidr-calculation b { color: var(--primary-strong); }
.network-calc-diagram { display: grid; gap: 14px; }
.network-calc-formula { display: grid; grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr) auto minmax(0, 1fr); gap: 8px; align-items: center; }
.network-calc-formula > div { display: grid; gap: 4px; justify-items: center; min-width: 0; padding: 11px 6px; border: 1px solid var(--line); border-radius: 10px; background: var(--surface); text-align: center; }
.network-calc-formula > div.is-result { border-color: var(--primary); background: color-mix(in srgb, var(--primary) 9%, var(--surface)); }
.network-calc-formula small, .network-calc-ranges small, .network-calc-result small { color: var(--muted); }
.network-calc-formula > span { color: var(--primary-strong); font-size: 20px; font-weight: 850; }
.network-calc-count { display: grid; gap: 4px; justify-items: center; padding: 12px; border-radius: 10px; background: var(--surface-soft); text-align: center; }
.network-calc-count span { color: var(--muted); font-size: 11px; }
.network-calc-count strong { font-size: 20px; }
.network-calc-count b { color: var(--primary-strong); }
.network-calc-guide { margin: 0; font-weight: 750; text-align: center; }
.network-calc-ranges { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 7px; }
.network-calc-ranges > div { display: grid; gap: 4px; justify-items: center; min-width: 0; padding: 11px 5px; border: 1px solid var(--line); border-radius: 9px; background: var(--surface); text-align: center; }
.network-calc-ranges > div.is-target { position: relative; border: 2px solid var(--primary); background: color-mix(in srgb, var(--primary) 10%, var(--surface)); }
.network-calc-ranges .is-target span { padding: 3px 8px; border-radius: 999px; background: var(--primary); color: var(--surface); font-size: 11px; font-weight: 800; }
.network-calc-result { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 7px; }
.network-calc-result > div { display: grid; gap: 5px; align-content: center; min-width: 0; padding: 12px 7px; border: 1px solid var(--accent); border-radius: 10px; background: color-mix(in srgb, var(--accent) 7%, var(--surface)); text-align: center; overflow-wrap: anywhere; }
.network-calc-result > div.is-host-range { border-color: var(--primary); background: color-mix(in srgb, var(--primary) 8%, var(--surface)); }
.network-calc-result b { color: var(--primary-strong); font-size: 11px; }
.subnetting-diagram { display: grid; gap: 14px; }
.subnet-origin { display: grid; gap: 8px; padding: 12px; border: 1px solid var(--line); border-radius: 11px; background: var(--surface); }
.subnet-origin > div:first-child { display: grid; gap: 3px; justify-items: center; text-align: center; }
.subnet-origin small, .subnet-prefix-formula small, .subnet-range-grid small { color: var(--muted); }
.subnet-bit-split { display: grid; grid-template-columns: 3fr 1fr; overflow: hidden; border-radius: 9px; }
.subnet-bit-split span { display: grid; gap: 2px; justify-items: center; padding: 9px 6px; background: var(--primary-soft); text-align: center; }
.subnet-bit-split span:last-child { background: color-mix(in srgb, var(--accent) 13%, var(--surface)); }
.subnet-bit-split b { font-size: 11px; }
.subnet-borrow { display: grid; gap: 8px; justify-items: center; padding: 12px; border-radius: 11px; background: var(--surface-soft); text-align: center; }
.subnet-borrow p { margin: 0; font-weight: 750; }
.subnet-borrow > div { display: grid; grid-template-columns: repeat(4, 42px); gap: 8px; }
.subnet-borrow > div span { display: grid; place-items: center; min-height: 38px; border-radius: 8px; background: var(--primary); color: var(--surface); font-family: ui-monospace, SFMono-Regular, Consolas, monospace; font-weight: 850; }
.subnet-borrow > strong { color: var(--primary-strong); }
.subnet-prefix-formula { display: grid; grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr) auto minmax(0, 1fr); gap: 8px; align-items: center; }
.subnet-prefix-formula > div { display: grid; gap: 4px; justify-items: center; min-width: 0; padding: 11px 6px; border: 1px solid var(--line); border-radius: 10px; background: var(--surface); text-align: center; }
.subnet-prefix-formula > div.is-result { border-color: var(--primary); background: color-mix(in srgb, var(--primary) 9%, var(--surface)); }
.subnet-prefix-formula > span { color: var(--primary-strong); font-size: 20px; font-weight: 850; }
.subnet-host-formula { display: grid; gap: 4px; justify-items: center; padding: 12px; border-radius: 10px; background: var(--surface-soft); text-align: center; }
.subnet-host-formula span { color: var(--muted); font-size: 11px; }
.subnet-host-formula strong { font-size: 18px; }
.subnet-host-formula b { color: var(--primary-strong); }
.subnet-range-grid { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 7px; }
.subnet-range-grid > div { display: grid; gap: 4px; justify-items: center; min-width: 0; padding: 11px 5px; border: 1px solid var(--primary); border-radius: 9px; background: color-mix(in srgb, var(--primary) 7%, var(--surface)); text-align: center; overflow-wrap: anywhere; }
.subnet-range-grid span { color: var(--primary-strong); font-size: 10px; font-weight: 800; }

.quiz-card { margin-top: 14px; }
.quiz-number { color: var(--primary-strong); font-weight: 800; font-size: 14px; }
.choice-list { display: grid; gap: 9px; margin: 14px 0; }
.choice { display: flex; gap: 10px; align-items: flex-start; padding: 12px; border: 1px solid var(--control-line); border-radius: 12px; cursor: pointer; background: var(--surface); }
.choice:hover { border-color: var(--primary); }
.choice input { margin-top: 5px; inline-size: 18px; block-size: 18px; }
.choice.correct { border-color: var(--success); background: var(--success-soft); }
.choice.incorrect { border-color: var(--danger); background: var(--danger-soft); }
.inline-error { color: var(--danger); font-weight: 700; margin: 8px 0; }
.feedback { margin-top: 14px; border-left: 5px solid var(--primary); background: var(--surface-soft); padding: 14px 16px; border-radius: 0 12px 12px 0; }
.feedback.success { border-color: var(--success); }
.feedback.error { border-color: var(--danger); }
.answer-explanation { margin-top: 10px; padding: 12px 14px; border: 1px solid var(--success); border-left-width: 5px; border-radius: 10px; background: color-mix(in srgb, var(--success) 9%, var(--surface)); }
.answer-explanation > :first-child { margin-top: 0; color: var(--success); font-weight: 800; }
.answer-explanation > :last-child { margin-bottom: 0; }
.question-support-actions { margin-top: 10px; }
.question-navigation { margin-top: 12px; }
.practice-stage .question-navigation {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
}
.practice-stage .question-navigation .button { width: 100%; }
.choice-reasons { margin-top: 12px; display: grid; gap: 7px; font-size: 14px; }
.glossary-hint { margin-bottom: 0; font-size: 13px; }
.question-references { margin-top: 12px; padding-top: 10px; border-top: 1px solid var(--border); font-size: 13px; }
.question-references summary { width: fit-content; cursor: pointer; color: var(--primary); font-weight: 700; }
.reference-intro { margin: 9px 0 0; }
.question-references ul { margin: 10px 0 0; padding-left: 20px; display: grid; gap: 8px; }
.question-references li strong { display: block; }
.question-references li small { display: block; margin-top: 2px; color: var(--muted); }
.question-references li > a { display: inline-block; margin-top: 4px; }
.reference-confirmed-at { margin: 9px 0 0; }
.hint { margin-top: 10px; padding: 10px 12px; background: color-mix(in srgb, var(--accent) 15%, var(--surface)); border-radius: 10px; }
.save-state { min-height: 22px; color: var(--muted); font-size: 13px; margin-top: 7px; }
.review-count { margin-top: 10px; }
.review-stage { margin-top: 18px; }
.lesson-nav { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 10px; margin-top: 18px; align-items: stretch; }
.lesson-nav .button {
  width: 100%;
  min-width: 0;
  min-height: 48px;
  align-self: stretch;
  justify-content: center;
  text-align: center;
  line-height: 1.35;
}
.lesson-nav .complete-button { white-space: nowrap; }
.lesson-top-action { display: flex; justify-content: center; margin-top: 14px; }
.inline-command {
  display: inline;
  padding: .1em .38em;
  border: 1px solid var(--control-line);
  border-radius: 6px;
  background: var(--surface-soft);
  color: var(--text);
  font-family: ui-monospace, SFMono-Regular, Consolas, "Liberation Mono", monospace;
  font-size: .92em;
  font-weight: 650;
  overflow-wrap: anywhere;
  box-decoration-break: clone;
  -webkit-box-decoration-break: clone;
}

.search-overlay[hidden] { display: none; }
.search-overlay { position: fixed; inset: 0; z-index: 120; background: rgba(16, 29, 34, .58); display: grid; place-items: start center; padding: 7vh 16px 16px; }
.search-dialog { width: min(680px, 100%); max-height: 82vh; overflow: auto; background: var(--surface); border-radius: 18px; box-shadow: 0 18px 60px rgba(0,0,0,.25); padding: 18px; }
.search-head { display: flex; gap: 10px; }
.search-input { flex: 1; min-height: 46px; border: 1px solid var(--control-line); border-radius: 12px; padding: 10px 13px; background: var(--bg); color: var(--text); }
.icon-button { width: 46px; height: 46px; border: 1px solid var(--control-line); border-radius: 12px; background: var(--surface); color: var(--text); cursor: pointer; }
.search-results { margin-top: 12px; display: grid; gap: 8px; }
.search-result { color: var(--text); text-decoration: none; padding: 12px; border: 1px solid var(--control-line); border-radius: 12px; }
.search-result:hover { border-color: var(--primary); background: var(--surface-soft); }
.search-result strong { display: block; }
.search-result span { color: var(--muted); font-size: 14px; }

.setting-row { display: flex; align-items: center; justify-content: space-between; gap: 18px; }
.backup-card { display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: 18px; align-items: center; }
.backup-card h2 { margin-bottom: 6px; }
.backup-card p { margin-bottom: 0; }
.backup-actions { display: flex; flex-wrap: wrap; justify-content: flex-end; gap: 10px; }
.backup-card [data-backup-status] { grid-column: 1 / -1; min-height: 1.4em; }
.restore-dialog { width: min(520px, calc(100% - 32px)); }
.study-stats { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 10px; margin: 0; }
.study-stats div { padding: 10px; border-radius: 11px; background: var(--surface-soft); }
.study-stats dt { color: var(--muted); font-size: 13px; }
.study-stats dd { margin: 3px 0 0; font-weight: 800; font-size: 20px; }
.compact-list { margin: 0; padding-left: 20px; }
.compact-list li + li { margin-top: 5px; }
.check-grid { display: grid; gap: 10px; }
.check-grid > label { font-weight: 700; }
.check-grid p { margin: -5px 0 4px 25px; }
.nested { grid-template-columns: repeat(2, minmax(0, 1fr)); margin-left: 25px; }
.select-control { min-height: 44px; min-width: 130px; margin: 2px 0 8px; padding: 8px 10px; border: 1px solid var(--control-line); border-radius: 10px; background: var(--surface); color: var(--text); }
.practice-option-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 10px; }
.option-card { display: flex; gap: 10px; align-items: flex-start; padding: 13px; border: 1px solid var(--control-line); border-radius: 12px; cursor: pointer; background: var(--surface); }
.option-card:has(input:checked) { border-color: var(--primary); background: var(--surface-soft); }
.option-card input { margin-top: 4px; inline-size: 18px; block-size: 18px; }
.option-card strong, .option-card small { display: block; }
.option-card small { margin-top: 4px; color: var(--muted); line-height: 1.5; }
.practice-stage { margin-top: 18px; }
.practice-resume, .practice-mistakes { margin-bottom: 16px; border-color: var(--primary); }
.practice-mistakes .button-row .button { min-width: 140px; }
.practice-quit { margin-top: 12px; }
.practice-result-list { display: grid; gap: 10px; margin: 18px 0; }
.result-question { padding: 13px 14px; border: 1px solid var(--line); border-left: 5px solid var(--success); border-radius: 10px; background: var(--surface-soft); }
.result-question.is-incorrect { border-left-color: var(--danger); }
.result-question h3 { margin: 0 0 8px; font-size: 16px; }
.result-question p { margin: 5px 0; }
.practice-result[hidden], .practice-stage[hidden], [data-practice-setup][hidden] { display: none; }
.mock-stage { margin-top: 18px; }
.mock-stage .quiz-card { position: relative; margin-bottom: 62px; }
.mock-stage [data-open-mock-finish] { position: absolute; right: 0; bottom: -54px; }
.mock-status { display: flex; justify-content: space-between; gap: 20px; margin-bottom: 12px; }
.mock-status div { display: grid; }
.mock-status strong { font-size: 20px; }
.mock-layout { display: grid; grid-template-columns: minmax(0, 1fr) 190px; gap: 12px; align-items: start; }
.mock-layout .quiz-card { margin-top: 0; }
.mock-palette { position: sticky; top: 14px; }
.mock-palette h2 { font-size: 17px; }
.question-palette { display: grid; grid-template-columns: repeat(4, 1fr); gap: 7px; }
.palette-button { min-height: 38px; border: 1px solid var(--control-line); border-radius: 9px; background: var(--surface); color: var(--text); cursor: pointer; }
.palette-button.is-answered { background: var(--primary-soft); border-color: var(--primary); }
.palette-button.is-current { outline: 3px solid color-mix(in srgb, var(--focus) 45%, transparent); outline-offset: 1px; }
.finish-dialog { width: min(520px, calc(100% - 24px)); color: var(--text); background: var(--surface); }
.finish-dialog::backdrop { background: rgba(16, 29, 34, .58); }
.mock-entry-grid > .card { display: flex; flex-direction: column; align-items: flex-start; }
.mock-entry-grid > .card .button { margin-top: auto; }
.mock-settings-layout { display: grid; grid-template-columns: minmax(0, 1fr) 260px; gap: 14px; align-items: start; }
.mock-setting-summary { position: sticky; top: 14px; }
.warning-note { padding: 10px 12px; border-left: 4px solid var(--accent); background: var(--surface-soft); }
.format-checks { margin-top: 14px; }
.selection-guide { margin: 0 0 8px; }
.order-item, .match-item {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: center;
  gap: 10px;
  padding: 10px 12px;
  border: 1px solid var(--control-line);
  border-radius: 11px;
  background: var(--surface);
}
.order-item { cursor: grab; }
.order-item.is-dragging { opacity: .55; }
.order-number {
  display: grid;
  place-items: center;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--primary-soft);
  color: var(--primary-strong);
  font-weight: 800;
}
.order-controls { display: flex; gap: 5px; }
.order-button {
  width: 38px;
  height: 38px;
  border: 1px solid var(--control-line);
  border-radius: 9px;
  background: var(--surface-soft);
  color: var(--text);
  cursor: pointer;
}
.order-button:disabled { opacity: .35; cursor: default; }
.match-item { grid-template-columns: minmax(120px, .75fr) minmax(0, 1.25fr); }
.match-item .select-control { width: 100%; margin: 0; }
.match-bank { display: flex; flex-wrap: wrap; gap: 8px; padding: 10px; border: 1px dashed var(--control-line); border-radius: 11px; }
.match-chip { min-height: 38px; padding: 7px 11px; border: 1px solid var(--control-line); border-radius: 999px; background: var(--surface-soft); color: var(--text); cursor: grab; }
.match-chip[aria-pressed="true"] { border-color: var(--primary); background: var(--primary-soft); color: var(--primary-strong); }
.command-response, .lab-response { display: grid; gap: 12px; }
.terminal-input {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  align-items: start;
  gap: 8px;
  padding: 12px;
  border-radius: 11px;
  background: #101b20;
  color: #dff7ed;
  font-family: ui-monospace, SFMono-Regular, Consolas, monospace;
}
.terminal-input span { padding-top: 9px; white-space: nowrap; }
.terminal-input textarea {
  width: 100%;
  min-height: 48px;
  resize: vertical;
  border: 1px solid #36515b;
  border-radius: 8px;
  padding: 8px 10px;
  background: #0b1418;
  color: #e9fff5;
  font: inherit;
}
.lab-device { padding: 9px 11px; border: 1px solid var(--line); border-radius: 10px; font-weight: 750; }
.lab-task-list { margin: 0; padding-left: 22px; }
.task-achieved { color: var(--success); }
.task-missed { color: var(--danger); }
.lab-result-items:empty, .correct-answer:empty { display: none; }
.result-summary-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 10px; margin: 16px 0; }
.result-summary-grid div { display: grid; padding: 12px; border-radius: 11px; background: var(--surface-soft); }
.result-summary-grid span { color: var(--muted); font-size: 13px; }
.result-summary-grid strong { font-size: 20px; }
.domain-results { display: grid; gap: 8px; margin-bottom: 16px; }
.domain-results div { display: flex; justify-content: space-between; gap: 12px; padding: 10px 12px; border: 1px solid var(--line); border-radius: 10px; }
.theme-options { display: flex; gap: 8px; }
.theme-button[aria-pressed="true"] { background: var(--primary); color: var(--on-primary); }
.danger-zone { border-color: color-mix(in srgb, var(--danger) 45%, var(--line)); }
.exam-version-note {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
}
.exam-version-note h2 { margin: 8px 0 4px; }
.exam-version-note p { margin: 0; }
.roadmap-chapter { padding: 0; overflow: visible; }
.roadmap-chapter + .roadmap-chapter { margin-top: 10px; }
.roadmap-chapter > summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 15px 16px;
  cursor: pointer;
  list-style: none;
}
.roadmap-chapter > summary::-webkit-details-marker { display: none; }
.roadmap-chapter > summary::after { content: "＋"; color: var(--primary-strong); font-size: 20px; font-weight: 800; }
.roadmap-chapter[open] > summary::after { content: "−"; }
.roadmap-chapter > summary > span:first-child { display: grid; gap: 2px; min-width: 0; }
.roadmap-chapter > summary small { color: var(--primary-strong); font-weight: 800; }
.roadmap-chapter > summary strong { font-size: 17px; }
.roadmap-chapter > summary span span { color: var(--muted); font-size: 13px; }
.roadmap-count { margin-left: auto; color: var(--muted); white-space: nowrap; font-size: 12px; }
.roadmap-rows { border-top: 1px solid var(--line); }
.roadmap-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: center;
  gap: 10px;
  color: var(--text);
  border-bottom: 1px solid var(--line);
}
.roadmap-row:last-child { border-bottom: 0; }
.roadmap-row:hover { background: var(--surface-soft); }
.roadmap-lesson-link {
  display: grid;
  grid-template-columns: 34px minmax(0, 1fr);
  align-items: center;
  gap: 10px;
  min-width: 0;
  padding: 11px 0 11px 16px;
  color: var(--text);
  text-decoration: none;
}
.roadmap-status-menu {
  position: relative;
  width: 92px;
  margin-right: 16px;
}
.roadmap-status-menu > summary {
  padding: 6px 24px 6px 9px;
  border: 1px solid var(--control-line);
  border-radius: 999px;
  background: var(--surface);
  color: var(--muted);
  font-size: 12px;
  font-weight: 750;
  cursor: pointer;
  list-style: none;
  white-space: nowrap;
}
.roadmap-status-menu > summary::-webkit-details-marker { display: none; }
.roadmap-status-menu > summary::after {
  content: "▾";
  position: absolute;
  right: 10px;
}
.roadmap-status-menu[open] > summary::after { content: "▴"; }
.roadmap-status-menu[data-status="learning"] > summary { border-color: var(--primary); color: var(--primary-strong); background: var(--primary-soft); }
.roadmap-status-menu[data-status="complete"] > summary { border-color: var(--success); color: var(--success); background: var(--success-soft); }
.roadmap-status-options {
  position: absolute;
  top: calc(100% + 5px);
  right: 0;
  z-index: 20;
  display: grid;
  width: 112px;
  padding: 5px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--surface);
  box-shadow: var(--shadow);
}
.roadmap-status-options button {
  padding: 7px 9px;
  border: 0;
  border-radius: 7px;
  background: transparent;
  color: var(--text);
  text-align: left;
  cursor: pointer;
}
.roadmap-status-options button:hover,
.roadmap-status-options button:focus-visible { background: var(--surface-soft); }
.roadmap-row.is-planned { color: var(--muted); background: color-mix(in srgb, var(--surface-soft) 55%, transparent); }
.roadmap-row.is-planned { grid-template-columns: 34px minmax(0, 1fr) auto; padding: 11px 16px; }
.roadmap-row .lesson-copy { display: grid; gap: 3px; }
.roadmap-kind { color: var(--muted); font-size: 12px; }
.roadmap-row.is-planned .status-badge { background: var(--surface-soft); color: var(--muted); }
.coverage-grid { display: grid; gap: 12px; }
.coverage-notice { border-left: 5px solid var(--primary); }
.coverage-notice p { margin-bottom: 0; }
.coverage-version-nav { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 14px; }
.exam-version-section { scroll-margin-top: 14px; }
.exam-version-header { display: flex; align-items: center; justify-content: space-between; gap: 18px; margin-bottom: 12px; }
.exam-version-header h2 { margin: 8px 0 2px; }
.exam-version-header p { margin: 0; color: var(--muted); }
.coverage-domain-head { display: flex; justify-content: space-between; align-items: flex-start; gap: 16px; }
.coverage-domain-head h2, .coverage-domain-head h3 { margin: 8px 0 2px; }
.coverage-domain-head p { margin: 0; }
.coverage-domain-head > strong { white-space: nowrap; }
.coverage-domain > p { margin-bottom: 0; color: var(--muted); }
.coverage-plan-count { margin-top: 8px; }
.coverage-objectives { margin-top: 12px; border: 1px solid var(--line); border-radius: 11px; overflow: clip; }
.coverage-objective + .coverage-objective { border-top: 1px solid var(--line); }
.coverage-objective > summary {
  display: grid;
  grid-template-columns: 48px minmax(0, 1fr) auto;
  align-items: center;
  gap: 8px;
  padding: 11px 12px;
  cursor: pointer;
  list-style: none;
  background: var(--surface);
}
.coverage-objective > summary::-webkit-details-marker { display: none; }
.coverage-objective > summary::after { content: "＋"; color: var(--primary-strong); font-weight: 900; }
.coverage-objective[open] > summary::after { content: "−"; }
.objective-id { color: var(--primary-strong); font-weight: 850; }
.coverage-objective-body { padding: 0 12px 12px 68px; background: var(--surface); }
.coverage-objective-body p { margin: 0 0 10px; }

.update-archive { display: grid; gap: 10px; }
.update-year { padding: 0; overflow: hidden; }
.update-year > summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 16px 18px;
  cursor: pointer;
  list-style: none;
}
.update-year > summary::-webkit-details-marker { display: none; }
.update-year > summary::after { content: "＋"; color: var(--primary-strong); font-weight: 900; }
.update-year[open] > summary::after { content: "−"; }
.update-year > summary span { margin-left: auto; color: var(--muted); font-size: 13px; }
.update-year-entries {
  display: grid;
  gap: 10px;
  padding: 0 12px 12px;
  border-top: 1px solid var(--line);
}
.update-year-entries .update-entry {
  margin: 12px 0 0;
  background: var(--surface-soft);
}
.updates-empty { color: var(--muted); }
.updates-empty p { margin: 0; }
.related-lessons { display: flex; flex-wrap: wrap; gap: 6px; align-items: center; }
.related-lessons b { margin-right: 3px; }
.related-lessons a, .related-lessons span {
  padding: 4px 8px;
  border-radius: 999px;
  background: var(--surface-soft);
  color: var(--text);
  font-size: 12px;
  text-decoration: none;
}
.related-lessons a { color: var(--primary-strong); font-weight: 750; }
.table-scroll { overflow-x: auto; }
.comparison-table { width: 100%; border-collapse: collapse; min-width: 620px; }
.comparison-table th, .comparison-table td { padding: 10px 11px; border: 1px solid var(--line); text-align: left; vertical-align: top; }
.comparison-table thead th { background: var(--surface-soft); }
.comparison-table tbody th { width: 130px; }

.bottom-nav { display: none; }
.footer { color: var(--muted); font-size: 13px; padding: 24px 0 6px; text-align: center; display: flex; justify-content: center; gap: 6px 14px; flex-wrap: wrap; }
.footer a { color: inherit; }
.footer-links { display: flex; justify-content: center; gap: 6px 14px; flex-wrap: wrap; width: 100%; }
.footer-trademark { width: 100%; max-width: 760px; margin: 5px auto 0; font-size: 11px; line-height: 1.55; }
.completed-lessons-panel > summary { display: flex; align-items: center; justify-content: space-between; gap: 12px; cursor: pointer; list-style: none; font-size: clamp(20px, 2.2vw, 25px); font-weight: 750; }
.completed-lessons-panel > summary::-webkit-details-marker { display: none; }
.completed-lessons-panel > summary::after { content: "＋"; color: var(--primary-strong); font-size: 20px; }
.completed-lessons-panel[open] > summary::after { content: "−"; }
.completed-lessons-panel > summary [data-completed-lessons-count] { margin-left: auto; font-size: 13px; font-weight: 600; }
.completed-lessons-panel > .summary-list { margin-top: 14px; }
.about-topic-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 10px; margin: 14px 0; }
.about-topic-grid > div { display: grid; gap: 3px; padding: 12px; border: 1px solid var(--line); border-radius: 12px; background: var(--surface-soft); }
.about-topic-grid span { color: var(--muted); font-size: 14px; }
.about-steps { list-style: none; padding: 0; margin: 0; }
.icon-option-grid { display: grid; gap: 14px; }
.icon-option { display: grid; grid-template-columns: 112px minmax(0, 1fr); align-items: center; gap: 18px; }
.icon-option img { display: block; width: 112px; height: 112px; border-radius: 22px; }
.icon-option h2 { margin-top: 8px; }
.icon-option p { margin-bottom: 0; }

@media (max-width: 560px) {
  .about-topic-grid { grid-template-columns: 1fr; }
  .icon-option { grid-template-columns: 72px minmax(0, 1fr); gap: 12px; }
  .icon-option img { width: 72px; height: 72px; border-radius: 16px; }
  .contact-type-grid { grid-template-columns: 1fr; }
}
.contact-template { white-space: pre-wrap; background: var(--surface-soft); border: 1px solid var(--line); border-radius: 10px; padding: 14px; }
.contact-form { display: grid; gap: 18px; }
.contact-form fieldset { min-width: 0; margin: 0; padding: 0; border: 0; }
.contact-form legend { margin-bottom: 10px; font-weight: 800; }
.contact-type-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 10px; }
.contact-fields { display: grid; gap: 14px; }
.contact-form > label,
.contact-fields > label { display: grid; gap: 6px; font-weight: 750; }
.contact-form label small { color: var(--muted); font-weight: 500; line-height: 1.5; }
.contact-form input[type="text"],
.contact-form input[type="url"],
.contact-form input[type="email"],
.contact-form select,
.contact-form textarea {
  width: 100%;
  min-width: 0;
  border: 1px solid var(--control-line);
  border-radius: 10px;
  padding: 10px 12px;
  background: var(--bg);
  color: var(--text);
}
.contact-form textarea { min-height: 150px; resize: vertical; }
.contact-honeypot {
  position: absolute;
  inline-size: 1px;
  block-size: 1px;
  overflow: hidden;
  clip-path: inset(50%);
}
.contact-privacy { margin: 0; color: var(--muted); font-size: 13px; }
.contact-status { min-height: 1.6em; margin: 0; font-weight: 700; }
.contact-status[data-kind="error"] { color: var(--danger); }
.contact-success { border-color: var(--success); }
.contact-success h2 { color: var(--success); }
.cf-turnstile { max-width: 100%; min-height: 65px; overflow: hidden; }
.visually-hidden { position: absolute!important; width: 1px!important; height: 1px!important; padding: 0!important; margin: -1px!important; overflow: hidden!important; clip: rect(0,0,0,0)!important; white-space: nowrap!important; border: 0!important; }

@media (min-width: 1024px) {
  body { font-size: 14px; }
  .content-wrap { padding-top: 20px; padding-bottom: 40px; }
  .lesson-page .diagram { width: min(100%, 680px); margin-inline: auto; }
  h1 { font-size: 26px; }
  h2 { font-size: 18px; margin-bottom: 9px; }
  .completed-lessons-panel > summary { font-size: 18px; }
  h3 { font-size: 16px; }
  .lead { font-size: 15px; margin-bottom: 14px; }
  .card { padding: 16px; border-radius: 15px; }
  .hero { padding: 22px; }
  .grid { gap: 12px; }
  .section { margin-top: 18px; }
  .section-head { margin-bottom: 9px; }
  .lesson-block { margin-top: 14px; }
  .choice-list { gap: 7px; margin: 11px 0; }
  .choice { padding: 9px 10px; }
  .button { min-height: 40px; padding: 8px 14px; }
  .feedback { margin-top: 11px; padding: 12px 14px; }
}

@media (max-width: 1023px) {
  .sidebar { width: var(--sidebar-closed); }
  .sidebar .nav-label, .sidebar .brand-text { opacity: 0; pointer-events: none; }
  .main-content, body.sidebar-collapsed .main-content { margin-left: var(--sidebar-closed); }
}

@media (max-width: 767px) {
  .abbreviation-note {
    gap: 4px 10px;
    font-size: 12px;
  }
  html, body, .app-shell { width: 100%; max-width: 100%; overflow-x: clip; }
  body { padding-bottom: var(--bottom-nav); }
  .sidebar { display: none; }
  .main-content,
  body.sidebar-collapsed .main-content,
  body.ui-ready:not(.sidebar-collapsed) .main-content,
  :root[data-sidebar-state="collapsed"] .main-content {
    width: 100%;
    max-width: 100%;
    margin-left: 0 !important;
  }
  .content-wrap { width: min(100% - 24px, 760px); padding-top: 18px; padding-bottom: 30px; }
  .hero, .card { padding: 16px; border-radius: 15px; }
  .practice-stage .question-navigation { grid-template-columns: repeat(3, minmax(0, 1fr)); }
  .practice-stage .question-navigation .button {
    min-width: 0;
    padding-inline: 6px;
    white-space: nowrap;
  }
  .grid-2 { grid-template-columns: 1fr; }
  .section { margin-top: 22px; }
  .ad-placeholder { min-height: 96px; padding: 12px; }
  .lesson-nav { grid-template-columns: 1fr 1fr; }
  .lesson-nav .complete-button { grid-column: 1 / -1; grid-row: 1; width: 100%; }
  .lesson-nav .previous { grid-column: 1; grid-row: 2; }
  .lesson-nav .next { grid-column: 2; grid-row: 2; }
  .lesson-top-action { display: none; }
  .vlan-topology { grid-template-columns: 1fr; }
  .ip-topology { grid-template-columns: 1fr; }
  .ip-delivery-map { grid-template-columns: 1fr; gap: 18px; }
  .ip-delivery-map > :not(:last-child)::after { content: "↓"; top: auto; right: 50%; bottom: -17px; transform: translateX(50%); }
  .ip-reply-note { display: grid; }
  .network-basic-topology,
  .lan-wan-topology,
  .delivery-topology,
  .client-server-topology,
  .model-comparison { grid-template-columns: 1fr; }
  .osi-map-group { grid-template-columns: 1fr; gap: 7px; padding: 8px; }
  .mapping-label { display: flex; gap: 7px; justify-content: center; padding-block: 1px; }
  .mapping-label::after { content: "↓"; font-size: 16px; }
  .osi-layer-list > div { grid-template-columns: 1fr; gap: 1px; }
  .osi-flow-edge { align-items: flex-start; }
  .tcpip-layer-label { padding: 9px 10px; }
  .vlan-lane { grid-template-columns: 1fr; gap: 5px; }
  .labeled-arrow { padding-block: 2px; }
  .labeled-arrow b { transform: rotate(90deg); }
  .trunk-map { grid-template-columns: 1fr; }
  .trunk-link { border: 0; border-left: 4px double var(--primary); border-right: 4px double var(--primary); }
  .trunk-link > b { transform: rotate(90deg); }
  .native-flow { grid-template-columns: 1fr; gap: 4px; text-align: center; }
  .native-flow > span[aria-hidden] { transform: rotate(90deg); }
  .component-map,
  .switch-role-map,
  .router-role-map,
  .ap-firewall-map { grid-template-columns: 1fr; }
  .virtualization-map,
  .cable-map,
  .poe-map,
  .duplex-map,
  .troubleshooting-flow { grid-template-columns: 1fr; }
  .mac-flow,
  .mac-learning-map,
  .arp-flow,
  .ping-flow,
  .tcpudp-map { grid-template-columns: 1fr; }
  .forwarding-board { grid-template-columns: 1fr; }
  .forwarding-source::after { content: "↓"; }
  .forwarding-case { grid-template-columns: 1fr; }
  .forwarding-label { text-align: center; }
  .arp-network, .arp-network.response { grid-template-columns: 1fr; direction: ltr; gap: 18px; }
  .arp-network > :not(:last-child)::after,
  .arp-network.response > :not(:last-child)::after { content: "↓"; top: auto; right: 50%; bottom: -17px; left: auto; transform: translateX(50%); }
  .arp-network.response .arp-receivers { order: 1; }
  .arp-network.response .arp-switch { order: 2; }
  .arp-network.response .arp-device { order: 3; }
  .arp-network.response > *::after { content: none; }
  .arp-network.response .arp-receivers::after,
  .arp-network.response .arp-switch::after { content: "↓"; position: absolute; top: auto; right: 50%; bottom: -17px; left: auto; transform: translateX(50%); color: var(--primary-strong); font-size: 19px; font-weight: 900; }
  .ping-trip { grid-template-columns: 1fr; }
  .ping-trip-label { justify-content: center; }
  .ping-route { grid-template-columns: 1fr; gap: 18px; }
  .ping-hop:not(:last-child)::after { content: "↓"; top: auto; right: 50%; bottom: -17px; transform: translateX(50%); }
  .ping-reading { grid-template-columns: 1fr; }
  .transport-addressing { grid-template-columns: 1fr; gap: 18px; }
  .transport-addressing > :not(:last-child)::after { content: "↓"; top: auto; right: 50%; bottom: -17px; transform: translateX(50%); }
  .transport-compare { grid-template-columns: 1fr; }
  .transport-compare ol { grid-template-columns: repeat(2, 1fr); }
  .component-arrow { transform: none; font-size: 0; }
  .component-arrow::after { content: "↓"; font-size: 22px; }
  .wireless-link { padding-block: 4px; }
  .wireless-link::after { content: "↓ 無線で接続"; font-size: 12px; }
  .topology-arrow { transform: none; font-size: 0; }
  .topology-arrow::after { content: "↕"; font-size: 22px; }
  .wan-link b { transform: none; font-size: 0; }
  .wan-link b::after { content: "↕"; font-size: 24px; }
  .delivery-topology .packet-chip { padding-block: 2px; }
  .delivery-topology .packet-chip:not(:nth-child(2)) { transform: none; font-size: 0; }
  .delivery-topology .packet-chip:not(:nth-child(2))::after { content: "↓ 次へ転送"; font-size: 12px; }
  .ip-flow { grid-template-columns: 1fr; }
  .ip-flow b { grid-column: 1; grid-row: auto; transform: none; font-size: 0; }
  .ip-flow b::after { content: "↓ 宛先へ転送"; font-size: 12px; }
  .ip-flow.simple b { display: inline-block; transform: none; }
  .topology-link { padding: 2px 0; font-size: 0; }
  .topology-link::after { content: "ケーブル  ↕"; font-size: 12px; }
  .endpoint-list small { margin-top: 2px; }
  .request-response [data-mobile-label] {
    padding: 7px 9px;
    border: 1px solid var(--line);
    border-radius: 8px;
    background: var(--surface);
    font-size: 0;
  }
  .request-response [data-mobile-label]::after { content: attr(data-mobile-label); font-size: 12px; }
  .labeled-flow-arrow { padding-block: 4px; }
  .labeled-flow-arrow b { font-size: 0; }
  .labeled-flow-arrow b::after { content: attr(data-mobile-label); font-size: 12px; }
  .concept-process,
  .concept-checklist,
  .concept-compare { grid-template-columns: 1fr; gap: 18px; }
  .concept-process li:not(:last-child)::after {
    content: "↓";
    top: auto;
    right: 50%;
    bottom: -19px;
    transform: translateX(50%);
  }
  .exchange-endpoints { gap: 20px; }
  .exchange-endpoints strong { padding: 8px 5px; font-size: 11px; }
  .concept-exchange li,
  .concept-exchange li.to-client {
    width: 100%;
    grid-template-columns: auto minmax(0, 1fr) 32px;
  }
  .concept-exchange li.to-client > i { grid-column: 3; }
  .concept-exchange li.to-client > b { grid-column: 1; }
  .concept-exchange li.to-client > span { grid-column: 2; }
  .concept-layers li { grid-template-columns: 72px 1fr; }
  .concept-decision li { grid-template-columns: 67px minmax(0, 1fr); width: 100%; }
  .concept-topology,
  .concept-protection { grid-template-columns: 1fr; gap: 18px; }
  .topology-center,
  .protection-core { width: min(230px, 86%); margin-inline: auto; border-radius: 14px; padding: 14px 12px; }
  .concept-topology ul { grid-template-columns: 1fr; gap: 9px; }
  .concept-topology li::before {
    top: -19px;
    left: 50%;
    width: 0;
    height: 18px;
    border-top: 0;
    border-left: 2px solid var(--diagram-arrow);
  }
  .complex-svg-diagram { padding: 13px 5px; }
  .learning-svg { width: 100%; }
  .learning-svg .svg-node-title,
  .learning-svg .svg-note-title { font-size: 20px; }
  .learning-svg .svg-node-copy { font-size: 17px; }
  .learning-svg .svg-link-label,
  .learning-svg .svg-warning-text,
  .learning-svg .svg-block-text { font-size: 16px; }
  .binary-place-grid { grid-template-columns: repeat(4, minmax(0, 1fr)); }
  .binary-reverse ol { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .host-address-row { grid-template-columns: 1fr; }
  .host-boundary { grid-template: auto / auto 1fr auto; align-items: center; }
  .host-boundary::before { content: "↓"; font-size: 18px; }
  .host-boundary span { width: 100%; height: 3px; }
  .cidr-octets { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .network-calc-formula { grid-template-columns: 1fr; }
  .network-calc-formula > span { line-height: 1; }
  .network-calc-ranges { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .network-calc-result { grid-template-columns: 1fr; }
  .subnet-prefix-formula { grid-template-columns: 1fr; }
  .subnet-prefix-formula > span { line-height: 1; }
  .subnet-range-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .troubleshooting-flow { gap: 20px; }
  .troubleshooting-flow li { position: relative; min-height: 0; }
  .troubleshooting-flow li:not(:last-child)::after {
    content: "↓ 次に確認";
    position: absolute;
    left: 50%;
    bottom: -18px;
    z-index: 2;
    transform: translateX(-50%);
    color: var(--primary-strong);
    font-size: 10px;
    font-weight: 800;
    white-space: nowrap;
  }
  .encapsulation-map { flex-direction: column; align-items: stretch; }
  .encapsulation-map span,
  .encapsulation-map b { text-align: center; }
  .encapsulation-map b::before { content: "↓ "; }
  .encapsulation-journey { grid-template-columns: 1fr; }
  .encapsulation-transit { padding: 4px 0; }
  .encapsulation-transit b { font-size: 0; }
  .encapsulation-transit b::after { content: "↓"; font-size: 26px; }
  .cable { border-top: 0; border-left: 4px solid var(--primary); border-right: 4px solid var(--primary); }
  .copper-link { border-left-style: double; border-right-style: double; }
  .fiber-link { border-left-color: var(--accent); border-right-color: var(--accent); }
  .vlan-topology .switch-box { order: 1; }
  .vlan-topology .topology-link { display: none; }
  .vlan-topology .vlan-sales { order: 2; }
  .vlan-topology .vlan-admin { order: 3; }
  .vlan-topology .vlan-box::before {
    content: "スイッチの設定ポートから接続";
    display: block;
    margin-bottom: 7px;
    color: var(--muted);
    font-size: 11px;
  }
  .bottom-nav { position: fixed; inset: auto 0 0; z-index: 70; height: var(--bottom-nav); display: grid; grid-template-columns: repeat(4, 1fr); background: var(--surface); border-top: 1px solid var(--line); transition: transform .2s ease; padding-bottom: env(safe-area-inset-bottom); }
  .bottom-nav.is-hidden { transform: translateY(110%); }
  .bottom-link { display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 1px; color: var(--muted); text-decoration: none; border: 0; background: transparent; font-size: 11px; min-width: 0; }
  .bottom-link span:first-child { font-size: 19px; line-height: 1.1; }
  .bottom-link[aria-current="page"] { color: var(--primary-strong); font-weight: 750; }
  .setting-row { align-items: flex-start; flex-direction: column; }
  .backup-card { grid-template-columns: 1fr; }
  .backup-actions { justify-content: stretch; }
  .backup-actions .button { width: 100%; }
  .backup-card [data-backup-status] { grid-column: auto; }
  .study-stats { grid-template-columns: 1fr; }
  .nested { grid-template-columns: 1fr; }
  .practice-option-grid { grid-template-columns: 1fr; }
  .practice-mistakes .button-row { align-items: stretch; flex-direction: column; }
  .practice-mistakes .button-row .button { width: 100%; }
  .mock-layout { grid-template-columns: 1fr; }
  .mock-palette { position: static; }
  .question-palette { grid-template-columns: repeat(5, 1fr); }
  .mock-controls .button { flex: 1 1 auto; }
  .mock-settings-layout { grid-template-columns: 1fr; }
  .mock-setting-summary { position: static; }
  .result-summary-grid { grid-template-columns: 1fr; }
  .exam-version-note { align-items: stretch; flex-direction: column; }
  .exam-version-note .button { width: 100%; }
  .roadmap-chapter > summary { align-items: flex-start; }
  .roadmap-count { display: none; }
  .roadmap-row { grid-template-columns: minmax(0, 1fr) auto; gap: 7px; }
  .roadmap-lesson-link { grid-template-columns: 30px minmax(0, 1fr); padding: 11px 0 11px 13px; }
  .roadmap-status-menu { width: 86px; margin-right: 10px; justify-self: end; }
  .roadmap-status-menu > summary { padding-inline: 8px 20px; }
  .roadmap-row.is-planned { grid-template-columns: 30px minmax(0, 1fr) auto; padding-inline: 13px; }
  .coverage-domain-head { flex-direction: column; }
  .exam-version-header { align-items: stretch; flex-direction: column; }
  .exam-version-header .button { width: 100%; }
  .coverage-version-nav { display: grid; grid-template-columns: 1fr; }
  .coverage-version-nav .button { width: 100%; }
  .coverage-objective > summary { grid-template-columns: 42px minmax(0, 1fr) auto; }
  .coverage-objective-body { padding-left: 12px; }
  .match-item { grid-template-columns: 1fr; }
  .terminal-input { grid-template-columns: 1fr; }
  .terminal-input span { padding-top: 0; }
  .order-item { grid-template-columns: auto minmax(0, 1fr); }
  .order-controls { grid-column: 2; justify-self: end; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { scroll-behavior: auto!important; transition-duration: .01ms!important; animation-duration: .01ms!important; }
}