/* LinkGuard multi-page presentation layer.
   Page routing is declared with body[data-page]; content, data and interactive components are unchanged. */

:root {
  --page-nav-height: 78px;
  --page-edge: clamp(20px, 4vw, 64px);
  --page-rule: rgba(11, 23, 38, .11);
  --page-muted: #637587;
  --page-ink: #0b1726;
  --page-cyan: #19bce5;
  --page-soft: #f5f8fa;
}

/* Real page composition: each document exposes only its assigned research chapters. */
body[data-page="home"] section:not(#summary),
body[data-page="system"] section:not(#composition):not(#functionality):not(#data),
body[data-page="research"] section:not(#background):not(#story):not(#compare),
body[data-page="field"] section:not(#field),
body[data-page="technical"] section:not(#deepdive):not(#roadmap),
body[data-page="team"] section:not(#team) {
  display: none !important;
}

body[data-page]:not([data-page="home"]) .hero {
  display: none !important;
}

html {
  scroll-padding-top: calc(var(--page-nav-height) + 22px);
}

body[data-page] {
  min-width: 320px;
  overflow-x: clip;
  background: #fff;
}

/* Navigation clarity across pages. */
body[data-page] .nav {
  min-height: var(--page-nav-height);
}

body[data-page] .nav-inner {
  min-height: var(--page-nav-height);
}

body[data-page] .nav-links {
  scrollbar-width: thin;
  scrollbar-color: rgba(25, 188, 229, .45) transparent;
}

body[data-page] .nav-links a {
  position: relative;
  white-space: nowrap;
}

body[data-page] .nav-links a::after {
  content: "";
  position: absolute;
  right: 12px;
  bottom: 7px;
  left: 12px;
  height: 2px;
  border-radius: 999px;
  background: var(--page-cyan);
  opacity: 0;
  transform: scaleX(.3);
  transition: opacity .18s ease, transform .18s ease;
}

body[data-page] .nav-links a:hover::after,
body[data-page] .nav-links a.active::after {
  opacity: 1;
  transform: scaleX(1);
}

body[data-page] .nav-links a.active {
  box-shadow: none;
}

/* Internal pages open like focused research chapters, not sliced landing-page bands. */
body[data-page]:not([data-page="home"]) section {
  border-bottom: 1px solid var(--page-rule);
}

body[data-page="system"] #composition,
body[data-page="research"] #background,
body[data-page="field"] #field,
body[data-page="technical"] #deepdive,
body[data-page="team"] #team {
  padding-top: clamp(140px, 14vw, 200px);
  background:
    radial-gradient(circle at 82% 0%, rgba(25, 188, 229, .10), transparent 31rem),
    linear-gradient(180deg, #f8fbfc 0%, #fff 34%);
}

body[data-page] section {
  position: relative;
}

body[data-page] section.alt {
  background: #f6f9fb;
}

/* Stable section rhythm and readable widths. */
body[data-page] section > .wrap {
  width: min(100% - (var(--page-edge) * 2), 1240px);
}

body[data-page] .sec-head {
  max-width: 880px;
  margin-bottom: clamp(38px, 5vw, 68px);
}

body[data-page] .sec-head .eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  color: #0b8fb0;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: .14em;
  text-transform: uppercase;
}

body[data-page] .sec-head .eyebrow::before {
  flex: 0 0 30px;
}

body[data-page] .sec-head h2,
body[data-page] .sec-head h2.l-zh,
body[data-page] .sec-head h2.l-en {
  max-width: 100%;
  margin-top: 16px;
  color: var(--page-ink);
  text-wrap: balance;
}

body[data-page] .sec-head p {
  max-width: 72ch;
  color: var(--page-muted);
  line-height: 1.82;
}

/* Consistent surfaces without flattening the different engineering modules. */
body[data-page] .card,
body[data-page] .unit,
body[data-page] .chart-card,
body[data-page] .place-card,
body[data-page] .road-card,
body[data-page] .member,
body[data-page] .acc-item,
body[data-page] .safety-block {
  border-color: rgba(11, 23, 38, .11);
  box-shadow: 0 1px 2px rgba(11, 23, 38, .025), 0 12px 34px rgba(11, 23, 38, .045);
}

body[data-page] .card:hover,
body[data-page] .unit:hover,
body[data-page] .chart-card:hover,
body[data-page] .place-card:hover,
body[data-page] .road-card:hover,
body[data-page] .member:hover {
  border-color: rgba(25, 188, 229, .5);
  box-shadow: 0 18px 44px rgba(11, 23, 38, .08);
}

body[data-page] .card p,
body[data-page] .unit p,
body[data-page] .member p,
body[data-page] .tl-body p {
  line-height: 1.75;
}

/* Tables and engineering diagrams retain an intentionally readable minimum width. */
body[data-page] .arch-wrap,
body[data-page] .diagram-wrap,
body[data-page] .table-wrap,
body[data-page] .compare-wrap {
  max-width: 100%;
  overflow-x: auto;
  overscroll-behavior-inline: contain;
  scrollbar-width: thin;
  scrollbar-color: rgba(25, 188, 229, .5) rgba(11, 23, 38, .06);
}

body[data-page] .arch-wrap::-webkit-scrollbar,
body[data-page] .diagram-wrap::-webkit-scrollbar,
body[data-page] .table-wrap::-webkit-scrollbar,
body[data-page] .compare-wrap::-webkit-scrollbar {
  height: 8px;
}

body[data-page] .arch-wrap::-webkit-scrollbar-thumb,
body[data-page] .diagram-wrap::-webkit-scrollbar-thumb,
body[data-page] .table-wrap::-webkit-scrollbar-thumb,
body[data-page] .compare-wrap::-webkit-scrollbar-thumb {
  background: rgba(25, 188, 229, .48);
  border-radius: 999px;
}

body[data-page] table {
  border-collapse: separate;
  border-spacing: 0;
}

body[data-page] th {
  color: #32475b;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: .08em;
}

body[data-page] td {
  line-height: 1.65;
}

/* Field media receives a contained editorial treatment on its dedicated page. */
body[data-page="field"] .gallery,
body[data-page="field"] .photo-wall {
  align-items: stretch;
}

body[data-page="field"] .photo-item,
body[data-page="field"] .photo-wall button {
  overflow: hidden;
  border: 1px solid rgba(11, 23, 38, .10);
  background: #eef3f5;
}

body[data-page="field"] .photo-item img,
body[data-page="field"] .photo-wall img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

body[data-page="field"] .video-player {
  margin-top: clamp(48px, 6vw, 80px);
  border: 1px solid rgba(11, 23, 38, .12);
  box-shadow: 0 24px 64px rgba(11, 23, 38, .10);
}

/* Team is a deliberate final chapter, with consistent portraits and award/footer spacing. */
body[data-page="team"] .team-grid {
  align-items: stretch;
}

body[data-page="team"] .member {
  height: 100%;
}

body[data-page] footer {
  border-top: 1px solid rgba(255, 255, 255, .11);
}

body[data-page] footer .credits {
  gap: clamp(28px, 4vw, 54px);
}

body[data-page] footer .credit-list {
  line-height: 1.7;
}

/* Anchor targets remain visible below the sticky navigation. */
body[data-page] section[id],
body[data-page] [id="video"] {
  scroll-margin-top: 0;
}

@media (max-width: 1180px) {
  body[data-page] .nav-links {
    gap: 0;
  }

  body[data-page] .nav-links a {
    padding-inline: 9px;
    font-size: 12px;
  }
}

@media (max-width: 900px) {
  :root {
    --page-nav-height: 68px;
    --page-edge: clamp(18px, 5vw, 40px);
  }

  body[data-page] .nav,
  body[data-page] .nav-inner {
    min-height: var(--page-nav-height);
  }

  body[data-page] .nav-links,
  html[data-device="mobile"] body[data-page] .nav-links,
  html[data-device="tablet"] body[data-page] .nav-links {
    top: var(--page-nav-height);
    max-height: calc(100svh - var(--page-nav-height));
    overflow-y: auto;
    overscroll-behavior: contain;
    padding: 10px var(--page-edge) 18px;
  }

  body[data-page] .nav-links a {
    min-height: 48px;
    padding: 13px 2px;
    border-bottom: 1px solid rgba(255, 255, 255, .08);
    font-size: 14px;
  }

  body[data-page] .nav-links a::after {
    top: 12px;
    right: auto;
    bottom: 12px;
    left: -10px;
    width: 2px;
    height: auto;
    transform: scaleY(.3);
  }

  body[data-page] .nav-links a:hover::after,
  body[data-page] .nav-links a.active::after {
    transform: scaleY(1);
  }

  body[data-page="system"] #composition,
  body[data-page="research"] #background,
  body[data-page="field"] #field,
  body[data-page="technical"] #deepdive,
  body[data-page="team"] #team {
    padding-top: clamp(112px, 18vw, 148px);
  }

  body[data-page] .sec-head {
    margin-bottom: 38px;
  }
}

@media (max-width: 700px) {
  :root {
    --page-edge: 18px;
  }

  body[data-page] section {
    padding-block: 72px;
  }

  body[data-page] .sec-head h2,
  body[data-page] .sec-head h2.l-zh,
  body[data-page] .sec-head h2.l-en {
    max-width: 100%;
    font-size: clamp(32px, 9vw, 44px);
    line-height: 1.16;
  }

  body[data-page] .sec-head p {
    font-size: 15px;
    line-height: 1.78;
  }

  body[data-page] .card,
  body[data-page] .unit,
  body[data-page] .chart-card,
  body[data-page] .place-card,
  body[data-page] .road-card,
  body[data-page] .member {
    border-radius: 16px;
  }

  body[data-page] .btn {
    min-height: 46px;
  }

  body[data-page] footer .credits {
    grid-template-columns: 1fr;
  }
}

@media (prefers-reduced-motion: reduce) {
  body[data-page] *,
  body[data-page] *::before,
  body[data-page] *::after {
    scroll-behavior: auto !important;
  }

  body[data-page] .nav-links a::after {
    transition: none;
  }
}


/* Post-deployment visual QA corrections. */
body[data-page] section .body-text strong,
body[data-page] section .sec-note strong,
body[data-page] section .desc strong,
body[data-page] section .acc-inner strong {
  color: inherit;
}

body[data-page] .sec-head h2,
body[data-page] .sec-head h2.l-zh,
body[data-page] .sec-head h2.l-en {
  font-size: clamp(36px, 4vw, 56px);
}

body[data-page] #composition .cards {
  align-items: start;
}

body[data-page] #composition .card {
  align-self: start;
}

body[data-page] #functionality .diagram-scroll {
  overflow-x: auto;
  border-color: #d8e5eb;
  background:
    linear-gradient(rgba(14, 165, 201, .055) 1px, transparent 1px),
    linear-gradient(90deg, rgba(14, 165, 201, .055) 1px, transparent 1px),
    #f7fbfc;
  background-size: 28px 28px;
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, .8);
}

body[data-page] #functionality .diagram {
  min-width: 780px;
  background: transparent;
  box-shadow: none;
}

body[data-page] #functionality .dg-box {
  fill: #fff;
  stroke: #b9d5de;
  stroke-width: 1.25;
}

body[data-page] #functionality .dg-label {
  fill: #0b1726;
  font-weight: 650;
}

body[data-page] #functionality .dg-sub,
body[data-page] #functionality .dg-link-label {
  fill: #52677d;
}

body[data-page] #functionality .dg-link {
  stroke: #62bcd0;
}

body[data-page] #functionality .dg-node.is-active .dg-box {
  fill: #eaf8fb;
  stroke: #19bce5;
}

body[data-page] #functionality .dg-node.is-active .dg-label {
  fill: #07131f;
}

body[data-page] .table-scroll,
body[data-page] .arch-scroll,
body[data-page] .diagram-scroll {
  max-width: 100%;
  overscroll-behavior-inline: contain;
  scrollbar-width: thin;
  scrollbar-color: rgba(25, 188, 229, .5) rgba(11, 23, 38, .06);
}

body[data-page] .modal .btn-primary {
  color: #06131a;
  background: #19bce5;
  border-color: #19bce5;
}

body[data-page] .modal .btn-primary:hover {
  color: #02090d;
  background: #45c9e8;
  border-color: #45c9e8;
}

@media (max-width: 700px) {
  body[data-page] .sec-head h2,
  body[data-page] .sec-head h2.l-zh,
  body[data-page] .sec-head h2.l-en {
    font-size: clamp(30px, 8.4vw, 42px);
  }

  body[data-page] #functionality .diagram-scroll {
    overflow-x: auto;
    padding: 12px;
  }

  body[data-page] #functionality .diagram {
    width: 780px;
    min-width: 780px;
  }
}