/* style.css */
:root {
  color-scheme: dark;
  --bg: #09111f;
  --bg-deep: #050a13;
  --surface: #111d30;
  --surface-raised: #17253b;
  --surface-soft: #0e192a;
  --text: #f3f7fc;
  --muted: #aebdd0;
  --faint: #7387a1;
  --line: rgba(189, 214, 241, 0.16);
  --line-strong: rgba(189, 214, 241, 0.28);
  --accent: #75d7ff;
  --accent-strong: #1ba6df;
  --accent-ink: #04131d;
  --gold: #f6c65b;
  --violet: #bb9cff;
  --mint: #7ce3be;
  --coral: #ff9b91;
  --shadow: 0 20px 60px rgba(0, 0, 0, 0.24);
  --radius: 18px;
  --body-font: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

@media (prefers-color-scheme: light) {
  :root {
    color-scheme: light;
    --bg: #eff5fb;
    --bg-deep: #e6eef8;
    --surface: #ffffff;
    --surface-raised: #f8fbff;
    --surface-soft: #f4f8fc;
    --text: #102238;
    --muted: #53677e;
    --faint: #76879a;
    --line: rgba(26, 63, 101, 0.14);
    --line-strong: rgba(26, 63, 101, 0.25);
    --accent: #087db8;
    --accent-strong: #006da7;
    --accent-ink: #ffffff;
    --gold: #a96a00;
    --violet: #6d4bc5;
    --mint: #047650;
    --coral: #c4544a;
    --shadow: 0 20px 50px rgba(35, 64, 94, 0.13);
  }
}

:root[data-theme="dark"] {
  color-scheme: dark;
  --bg: #09111f;
  --bg-deep: #050a13;
  --surface: #111d30;
  --surface-raised: #17253b;
  --surface-soft: #0e192a;
  --text: #f3f7fc;
  --muted: #aebdd0;
  --faint: #7387a1;
  --line: rgba(189, 214, 241, 0.16);
  --line-strong: rgba(189, 214, 241, 0.28);
  --accent: #75d7ff;
  --accent-strong: #1ba6df;
  --accent-ink: #04131d;
  --gold: #f6c65b;
  --violet: #bb9cff;
  --mint: #7ce3be;
  --coral: #ff9b91;
  --shadow: 0 20px 60px rgba(0, 0, 0, 0.24);
}

:root[data-theme="light"] {
  color-scheme: light;
  --bg: #eff5fb;
  --bg-deep: #e6eef8;
  --surface: #ffffff;
  --surface-raised: #f8fbff;
  --surface-soft: #f4f8fc;
  --text: #102238;
  --muted: #53677e;
  --faint: #76879a;
  --line: rgba(26, 63, 101, 0.14);
  --line-strong: rgba(26, 63, 101, 0.25);
  --accent: #087db8;
  --accent-strong: #006da7;
  --accent-ink: #ffffff;
  --gold: #a96a00;
  --violet: #6d4bc5;
  --mint: #047650;
  --coral: #c4544a;
  --shadow: 0 20px 50px rgba(35, 64, 94, 0.13);
}

* { box-sizing: border-box; }

html {
  background: var(--bg-deep);
  scroll-behavior: smooth;
}

body {
  min-width: 320px;
  min-height: 100dvh;
  margin: 0;
  overflow-x: hidden;
  background:
    radial-gradient(circle at 8% -10%, color-mix(in srgb, var(--accent) 13%, transparent), transparent 28rem),
    radial-gradient(circle at 94% 18%, color-mix(in srgb, var(--violet) 10%, transparent), transparent 30rem),
    var(--bg);
  color: var(--text);
  font-family: var(--body-font);
  line-height: 1.55;
}

button, input { font: inherit; }
button, a, input { -webkit-tap-highlight-color: transparent; }
button { cursor: pointer; }

button:focus-visible,
a:focus-visible,
input:focus-visible {
  outline: 3px solid var(--accent);
  outline-offset: 3px;
}

a {
  color: inherit;
  text-underline-offset: 0.18em;
}

.site-shell {
  width: min(1440px, 100%);
  margin: 0 auto;
  padding: 0 max(18px, env(safe-area-inset-left)) calc(76px + env(safe-area-inset-bottom));
}

.topbar {
  min-height: 76px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  border-bottom: 1px solid var(--line);
}

.brand {
  min-width: 0;
  display: inline-flex;
  align-items: center;
  gap: 11px;
  text-decoration: none;
}

.brand-mark {
  width: 43px;
  height: 43px;
  flex: 0 0 auto;
  display: grid;
  place-items: center;
  border: 1px solid color-mix(in srgb, var(--accent) 48%, transparent);
  border-radius: 14px;
  color: var(--accent);
  background: color-mix(in srgb, var(--accent) 8%, transparent);
}

.brand-mark svg { width: 29px; height: 29px; }
.brand strong, .brand small { display: block; white-space: nowrap; }
.brand strong { font-size: .95rem; line-height: 1.15; letter-spacing: .01em; }
.brand small { margin-top: 3px; color: var(--muted); font-size: .72rem; line-height: 1.2; }

.top-actions { display: flex; gap: 8px; }

.icon-button {
  width: 44px;
  height: 44px;
  display: grid;
  place-items: center;
  border: 1px solid var(--line);
  border-radius: 13px;
  color: var(--muted);
  background: color-mix(in srgb, var(--surface) 80%, transparent);
  transition: 160ms ease;
}

.icon-button:hover {
  border-color: var(--line-strong);
  color: var(--accent);
  background: var(--surface-raised);
}

.icon-button svg { width: 21px; height: 21px; }

.hero {
  display: grid;
  gap: 28px;
  padding: clamp(42px, 7vw, 90px) 0 clamp(30px, 5vw, 58px);
}

.eyebrow, .card-label {
  margin: 0;
  color: var(--accent);
  font-size: .72rem;
  font-weight: 800;
  letter-spacing: .13em;
  line-height: 1.25;
  text-transform: uppercase;
}

.hero h1,
.detail-panel h2,
.guide-section h2,
.sources-section h2 {
  margin: 0;
  letter-spacing: -.045em;
  line-height: 1.03;
}

.hero h1 {
  max-width: 850px;
  margin-top: 10px;
  font-size: clamp(2.45rem, 7vw, 5.6rem);
}

.hero-text {
  max-width: 760px;
  margin: 20px 0 0;
  color: var(--muted);
  font-size: clamp(1.02rem, 2.1vw, 1.22rem);
}

.hero-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  max-width: 520px;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: color-mix(in srgb, var(--surface) 74%, transparent);
  box-shadow: var(--shadow);
}

.hero-stats div { min-width: 0; padding: 17px 13px; text-align: center; }
.hero-stats div + div { border-left: 1px solid var(--line); }
.hero-stats strong, .hero-stats span { display: block; }
.hero-stats strong { font-size: clamp(1.35rem, 5vw, 2.1rem); line-height: 1.1; }
.hero-stats span { margin-top: 4px; color: var(--muted); font-size: .74rem; }

.explore-bar {
  display: grid;
  gap: 17px;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: color-mix(in srgb, var(--surface) 88%, transparent);
  box-shadow: var(--shadow);
}

.search-wrap label, .filter-label {
  display: block;
  margin-bottom: 7px;
  color: var(--muted);
  font-size: .76rem;
  font-weight: 700;
}

.search-field {
  min-height: 47px;
  display: flex;
  align-items: center;
  gap: 9px;
  padding: 0 13px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--bg-deep);
  color: var(--faint);
}

.search-field:focus-within {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--accent) 15%, transparent);
}

.search-field svg { width: 20px; height: 20px; flex: 0 0 auto; }
.search-field input { width: 100%; min-width: 0; border: 0; outline: 0; color: var(--text); background: transparent; }
.search-field input::placeholder { color: var(--faint); }

.filters {
  display: flex;
  gap: 8px;
  overflow-x: auto;
  padding-bottom: 2px;
  scrollbar-width: thin;
}

.filter-button {
  min-height: 44px;
  flex: 0 0 auto;
  padding: 0 13px;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--muted);
  background: var(--surface-soft);
  font-size: .83rem;
  font-weight: 700;
  transition: 150ms ease;
}

.filter-button:hover { border-color: var(--line-strong); color: var(--text); }
.filter-button.is-active { border-color: var(--accent); color: var(--accent-ink); background: var(--accent); }

.timeline-layout {
  display: grid;
  gap: 18px;
  margin-top: 18px;
}

.timeline-rail, .detail-panel {
  min-width: 0;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: color-mix(in srgb, var(--surface) 91%, transparent);
  box-shadow: var(--shadow);
}

.timeline-rail { overflow: hidden; }
.rail-heading { padding: 19px 18px 14px; border-bottom: 1px solid var(--line); }
.rail-heading p:last-child { margin: 5px 0 0; color: var(--muted); font-size: .84rem; }

.timeline-list {
  position: relative;
  max-height: min(53dvh, 660px);
  overflow-y: auto;
  padding: 12px 10px 18px;
  scrollbar-width: thin;
}

.timeline-list::before {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  left: 29px;
  width: 1px;
  background: var(--line);
}

.period-marker {
  position: relative;
  z-index: 1;
  margin: 15px 0 7px 43px;
  color: var(--faint);
  font-size: .68rem;
  font-weight: 800;
  letter-spacing: .14em;
}

.timeline-item {
  position: relative;
  width: 100%;
  min-height: 62px;
  display: grid;
  grid-template-columns: 21px 42px minmax(0, 1fr);
  gap: 7px;
  align-items: start;
  padding: 9px 8px 9px 0;
  border: 1px solid transparent;
  border-radius: 12px;
  color: var(--text);
  text-align: left;
  background: transparent;
  transition: background 150ms ease, border-color 150ms ease;
}

.timeline-item:hover { background: color-mix(in srgb, var(--accent) 7%, transparent); }
.timeline-item.is-active { border-color: color-mix(in srgb, var(--accent) 45%, transparent); background: color-mix(in srgb, var(--accent) 13%, transparent); }
.timeline-item.is-active .timeline-title { color: var(--accent); }

.timeline-node {
  z-index: 1;
  width: 13px;
  height: 13px;
  justify-self: center;
  margin-top: 4px;
  border: 3px solid var(--surface);
  border-radius: 50%;
  background: var(--faint);
  box-shadow: 0 0 0 1px var(--line-strong);
}

.timeline-item.is-active .timeline-node { box-shadow: 0 0 0 4px color-mix(in srgb, var(--accent) 18%, transparent); }
.category-foundations { --category-color: var(--gold); }
.category-protocols { --category-color: var(--accent); }
.category-web { --category-color: var(--violet); }
.category-business { --category-color: var(--coral); }
.category-access { --category-color: var(--mint); }
.category-mobile { --category-color: #e595ff; }
.category-cloud { --category-color: #74a8ff; }
.timeline-node[class*="category-"] { background: var(--category-color); }

.timeline-year {
  padding-top: 1px;
  color: var(--faint);
  font-size: .76rem;
  font-weight: 800;
  font-variant-numeric: tabular-nums;
}

.timeline-item-copy { min-width: 0; }
.timeline-title, .timeline-category { display: block; }
.timeline-title { overflow: hidden; font-size: .87rem; font-weight: 720; line-height: 1.25; text-overflow: ellipsis; }
.timeline-category { margin-top: 3px; color: var(--faint); font-size: .68rem; }

.empty-state {
  position: relative;
  z-index: 1;
  margin: 24px 8px;
  padding: 20px;
  border: 1px dashed var(--line-strong);
  border-radius: 14px;
  background: var(--surface-soft);
}

.empty-state strong { display: block; }
.empty-state p { margin: 5px 0 12px; color: var(--muted); font-size: .88rem; }

.text-button {
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  gap: 7px;
  border: 0;
  color: var(--accent);
  background: transparent;
  font-weight: 750;
}

.text-button svg { width: 18px; height: 18px; }

.detail-panel {
  padding: clamp(21px, 4vw, 48px);
  overflow: hidden;
}

.detail-topline, .detail-meta, .detail-actions, .nearby-nav {
  display: flex;
  align-items: center;
}

.detail-topline { justify-content: space-between; gap: 12px; }
.detail-meta { gap: 11px; }
.detail-meta time { color: var(--muted); font-size: .94rem; font-variant-numeric: tabular-nums; }

.category-pill {
  display: inline-flex;
  align-items: center;
  min-height: 27px;
  padding: 0 9px;
  border: 1px solid color-mix(in srgb, var(--category-color) 46%, transparent);
  border-radius: 999px;
  color: var(--category-color);
  background: color-mix(in srgb, var(--category-color) 9%, transparent);
  font-size: .7rem;
  font-weight: 800;
}

.save-button, .read-button {
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 7px;
  padding: 0 12px;
  border: 1px solid var(--line-strong);
  border-radius: 11px;
  color: var(--text);
  background: var(--surface-soft);
  font-size: .8rem;
  font-weight: 750;
  transition: 160ms ease;
}

.save-button:hover, .read-button:hover { border-color: var(--accent); }
.save-button.is-saved, .read-button.is-read {
  border-color: color-mix(in srgb, var(--accent) 50%, transparent);
  color: var(--accent);
  background: color-mix(in srgb, var(--accent) 10%, transparent);
}

.save-button svg, .read-button svg, .source-link svg { width: 18px; height: 18px; }

.signal-line {
  width: min(230px, 60%);
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin: 30px 0 21px;
}

.signal-line::before, .signal-line::after {
  content: "";
  height: 1px;
  flex: 1;
  background: linear-gradient(90deg, transparent, var(--accent), transparent);
}

.signal-line span {
  width: 5px;
  height: 5px;
  margin: 0 5px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 12px color-mix(in srgb, var(--accent) 80%, transparent);
}

.detail-panel h2 { max-width: 900px; font-size: clamp(2rem, 5vw, 4.3rem); }
.detail-summary { max-width: 850px; margin: 21px 0 0; color: var(--muted); font-size: clamp(1.04rem, 2vw, 1.23rem); line-height: 1.63; }

.detail-grid { display: grid; gap: 12px; margin-top: 30px; }
.why-card, .connection-card { padding: 19px; border-radius: 14px; }
.why-card { border: 1px solid color-mix(in srgb, var(--accent) 25%, var(--line)); background: color-mix(in srgb, var(--accent) 8%, var(--surface-soft)); }
.connection-card { border: 1px solid var(--line); background: var(--surface-soft); }
.why-card p:last-child, .connection-card p:last-child { margin: 8px 0 0; color: var(--muted); font-size: .92rem; }

.evidence-card {
  display: grid;
  gap: 17px;
  margin-top: 13px;
  padding: 19px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: var(--surface-soft);
}

.evidence-card h3 { margin: 7px 0 3px; font-size: .96rem; line-height: 1.34; }
.evidence-card p:last-child { margin: 0; color: var(--faint); font-size: .77rem; }

.source-link {
  min-height: 44px;
  width: fit-content;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 0 13px;
  border-radius: 10px;
  color: var(--accent-ink);
  background: var(--accent);
  font-size: .82rem;
  font-weight: 800;
  text-decoration: none;
}

.source-link:hover { filter: brightness(1.08); }

.detail-actions {
  flex-wrap: wrap;
  gap: 13px;
  margin-top: 23px;
}

.keyboard-hint { color: var(--faint); font-size: .75rem; }

.nearby-nav {
  justify-content: space-between;
  gap: 10px;
  margin-top: 36px;
  padding-top: 18px;
  border-top: 1px solid var(--line);
}

.nearby {
  width: min(47%, 270px);
  min-height: 56px;
  display: grid;
  gap: 2px;
  padding: 0;
  border: 0;
  color: var(--text);
  text-align: left;
  background: transparent;
}

.nearby:hover strong { color: var(--accent); }
.nearby span { color: var(--faint); font-size: .67rem; font-weight: 800; letter-spacing: .11em; text-transform: uppercase; }
.nearby strong { overflow: hidden; font-size: .79rem; line-height: 1.3; text-overflow: ellipsis; white-space: nowrap; transition: color 150ms ease; }

.nearby.next {
  position: relative;
  padding-right: 30px;
  text-align: right;
}

.nearby-arrow {
  position: absolute;
  top: 50%;
  right: 0;
  width: 22px;
  height: 22px;
  color: var(--accent);
  transform: translateY(-50%);
}

.nearby-arrow svg { width: 22px; height: 22px; }

.guide-section, .sources-section {
  display: grid;
  gap: 25px;
  margin-top: 66px;
  padding-top: 35px;
  border-top: 1px solid var(--line);
}

.guide-section h2, .sources-section h2 { margin-top: 8px; font-size: clamp(1.75rem, 4vw, 3rem); }
.guide-grid { display: grid; gap: 11px; }

.guide-grid article {
  min-height: 150px;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: color-mix(in srgb, var(--surface) 78%, transparent);
}

.guide-number { color: var(--accent); font-size: .72rem; font-weight: 850; letter-spacing: .13em; }
.guide-grid h3 { margin: 11px 0 6px; font-size: 1rem; }
.guide-grid p { margin: 0; color: var(--muted); font-size: .87rem; }

.sources-intro { max-width: 720px; }
.sources-intro > p:last-child { margin: 14px 0 0; color: var(--muted); }

.sources-list {
  display: grid;
  gap: 0;
  margin: 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--line);
}

.sources-list li {
  display: grid;
  grid-template-columns: 40px minmax(0, 1fr);
  gap: 10px;
  padding: 15px 0;
  border-bottom: 1px solid var(--line);
}

.source-number { padding-top: 2px; color: var(--accent); font-size: .73rem; font-weight: 850; font-variant-numeric: tabular-nums; }
.sources-list a { color: var(--text); font-size: .91rem; font-weight: 720; }
.sources-list a:hover { color: var(--accent); }
.sources-list p { margin: 3px 0 0; color: var(--faint); font-size: .76rem; }

footer {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 13px 26px;
  margin-top: 48px;
  padding-top: 20px;
  border-top: 1px solid var(--line);
  color: var(--faint);
  font-size: .77rem;
}

footer p { max-width: 700px; margin: 0; }
footer a { color: var(--accent); font-weight: 750; }

.toast {
  position: fixed;
  z-index: 20;
  right: max(16px, env(safe-area-inset-right));
  bottom: calc(17px + env(safe-area-inset-bottom));
  max-width: min(360px, calc(100vw - 32px));
  padding: 12px 15px;
  border: 1px solid color-mix(in srgb, var(--accent) 38%, var(--line));
  border-radius: 11px;
  color: var(--text);
  background: color-mix(in srgb, var(--surface-raised) 94%, var(--bg-deep));
  box-shadow: var(--shadow);
  font-size: .86rem;
  font-weight: 650;
  opacity: 0;
  pointer-events: none;
  transform: translateY(14px);
  transition: opacity 180ms ease, transform 180ms ease;
}

.toast.is-visible { opacity: 1; transform: translateY(0); }

@media (min-width: 620px) {
  .site-shell {
    padding-right: max(28px, env(safe-area-inset-right));
    padding-left: max(28px, env(safe-area-inset-left));
  }

  .hero {
    grid-template-columns: minmax(0, 1fr) minmax(300px, .55fr);
    align-items: end;
  }

  .hero-stats { justify-self: end; width: 100%; }
  .explore-bar { grid-template-columns: minmax(250px, .8fr) minmax(280px, 1.2fr); align-items: end; }
  .detail-grid { grid-template-columns: 1fr 1fr; }
  .evidence-card { grid-template-columns: minmax(0, 1fr) auto; align-items: center; }
  .guide-grid { grid-template-columns: repeat(2, 1fr); }
  .sources-list { grid-template-columns: 1fr 1fr; column-gap: 35px; }
}

@media (min-width: 980px) {
  .site-shell {
    padding-right: max(42px, env(safe-area-inset-right));
    padding-left: max(42px, env(safe-area-inset-left));
  }

  .timeline-layout {
    grid-template-columns: minmax(308px, .57fr) minmax(0, 1.43fr);
    align-items: start;
  }

  .timeline-rail { position: sticky; top: 18px; }
  .timeline-list { max-height: calc(100dvh - 176px); }
  .guide-section, .sources-section { grid-template-columns: minmax(240px, .55fr) minmax(0, 1.45fr); }
  .sources-list { grid-template-columns: 1fr; }
}

@media (min-width: 1240px) {
  .guide-grid { grid-template-columns: repeat(4, 1fr); }
  .guide-grid article { min-height: 182px; }
}

@media (max-height: 610px) and (orientation: landscape) {
  .topbar { min-height: 59px; }
  .brand small { display: none; }
  .hero { padding: 25px 0; }
  .hero h1 { font-size: 2.5rem; }
  .hero-text { margin-top: 10px; font-size: .94rem; }
  .timeline-list { max-height: 55dvh; }
}