:root {
  --bg: #F1F2EE;
  --stage: #FBFBF9;
  --surface: #FFFFFF;
  --surface-2: #E7E8E2;
  --ink: #1B2027;
  --ink-dim: #5B6470;
  --ink-faint: #8A929C;
  --you: #B96A1E;
  --you-soft: #F2E2CE;
  --claude: #1F7A6C;
  --claude-soft: #DCEEEA;
  --accent: #B96A1E;
  --accent-soft: #F2E2CE;
  --accent-2: #1F7A6C;
  --accent-2-soft: #DCEEEA;
  --pre: #B96A1E;
  --pre-soft: #F2E2CE;
  --post: #1F7A6C;
  --post-soft: #DCEEEA;
  --client: #B96A1E;
  --client-soft: #F2E2CE;
  --server: #1F7A6C;
  --server-soft: #DCEEEA;
  --gate: #1F7A6C;
  --gate-soft: #DCEEEA;
  --parent: #B96A1E;
  --parent-soft: #F2E2CE;
  --sub: #1F7A6C;
  --sub-soft: #DCEEEA;
  --accent-ink: #FFFFFF;
  --line: #D8D9D2;
  --line-strong: #C2C4BB;
  --grid: rgba(27, 32, 39, 0.07);
  --good: #2E7D4F;
  --good-soft: #DCEFE1;
  --bad: #B23A32;
  --bad-soft: #F7E1DE;
  --warn: #946E1A;
  --warn-soft: #F2E9CE;
  --shadow: 0 30px 60px -30px rgba(20, 20, 15, 0.35), 0 2px 8px rgba(20, 20, 15, 0.06);
}

:root[data-theme="dark"] {
  --bg: #10141A;
  --stage: #161C24;
  --surface: #1B222B;
  --surface-2: #212A34;
  --ink: #F5F7FA;
  --ink-dim: #C7D0DB;
  --ink-faint: #9EABB9;
  --you: #E8A33D;
  --you-soft: #3A2E1B;
  --claude: #57C2B2;
  --claude-soft: #173832;
  --accent: #E8A33D;
  --accent-soft: #3A2E1B;
  --accent-2: #57C2B2;
  --accent-2-soft: #173832;
  --pre: #E8A33D;
  --pre-soft: #3A2E1B;
  --post: #57C2B2;
  --post-soft: #173832;
  --client: #E8A33D;
  --client-soft: #3A2E1B;
  --server: #57C2B2;
  --server-soft: #173832;
  --gate: #57C2B2;
  --gate-soft: #173832;
  --parent: #E8A33D;
  --parent-soft: #3A2E1B;
  --sub: #57C2B2;
  --sub-soft: #173832;
  --accent-ink: #151004;
  --line: #465364;
  --line-strong: #AAB6C5;
  --grid: rgba(255, 255, 255, 0.07);
  --good: #4FAE78;
  --good-soft: #173225;
  --bad: #E0685E;
  --bad-soft: #3A211E;
  --warn: #E0B94D;
  --warn-soft: #332A14;
  --shadow: 0 30px 60px -30px rgba(0, 0, 0, 0.7), 0 2px 8px rgba(0, 0, 0, 0.4);
}

body {
  background:
    radial-gradient(circle at 1px 1px, var(--grid) 1.4px, transparent 1.4px) 0 0 / 28px 28px,
    var(--bg);
}

.deck {
  width: 100%;
  max-width: 1220px;
  display: flex;
  flex-direction: column;
  gap: clamp(10px, 1.6vh, 16px);
}

.stage-wrap {
  background: var(--stage);
  border: 1px solid var(--line);
  border-radius: 18px;
  box-shadow: var(--shadow);
}

.slide {
  padding: clamp(14px, 2.6vw, 30px) clamp(24px, 5vw, 60px);
}

h2.title {
  margin-top: clamp(3px, .65vh, 7px);
  font-size: clamp(25px, 4vw, 42px);
}

.lede {
  margin-top: clamp(5px, .9vh, 8px);
  font-size: clamp(13.5px, 1.5vw, 16.5px);
  line-height: 1.46;
}

.body-area {
  margin-top: clamp(6px, 1.2vh, 12px);
  gap: 9px;
}

.card h3 {
  font-size: clamp(14px, 1.6vw, 17px);
}

.card p {
  font-size: clamp(12.5px, 1.32vw, 14.5px);
  line-height: 1.44;
}

.ftable {
  font-size: clamp(12px, 1.3vw, 14.25px);
}

.ftable th {
  font-size: 11px;
}

.code-col pre {
  font-size: clamp(11.2px, 1.15vw, 13.3px);
  line-height: 1.5;
}

.callout {
  font-size: clamp(12.3px, 1.25vw, 14px);
  line-height: 1.44;
}

.diagram .label {
  font-size: 12.5px;
}

.diagram .node-title {
  font-size: 14.5px;
}

.diagram .node-sub {
  font-size: 11.5px;
}

.diagram marker {
  overflow: visible;
}

.cover .sub {
  font-size: clamp(14.5px, 1.7vw, 19px);
}

.source {
  font-size: 10.5px;
}

.controls {
  display: flex;
  align-items: center;
  gap: clamp(8px, 1.4vw, 14px);
  padding: 0 4px;
}

.nav-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 38px;
  height: 38px;
  border-radius: 50%;
  background: var(--surface);
  border: 1px solid var(--line);
  color: var(--ink);
  cursor: pointer;
  flex: none;
  transition: background .15s ease, border-color .15s ease, transform .1s ease;
}

.nav-btn:hover,
.theme-btn:hover {
  border-color: var(--you);
  color: var(--you);
}

.theme-btn {
  width: auto;
  min-width: 92px;
  padding: 0 13px;
  border-radius: 19px;
  font-family: "IBM Plex Mono", monospace;
  font-size: 11px;
  font-weight: 600;
  white-space: nowrap;
}

.track {
  flex: 1;
  display: flex;
  align-items: center;
  gap: clamp(10px, 1.4vw, 16px);
  overflow-x: auto;
  scrollbar-width: none;
  padding: 2px 0;
}

.dot-btn:hover {
  border-color: var(--you);
  color: var(--you);
}

.dot-btn.is-current {
  background: var(--you);
  border-color: var(--you);
  color: var(--accent-ink);
  font-weight: 600;
}

.progress i {
  background: linear-gradient(90deg, var(--you), var(--claude));
}

.theme-picker {
  display: none;
}

.hint {
  display: none;
}

.deck-slide-selector, .deck-navigation-dock[hidden] { display: none; }

/* The slide surface rotates; navigation stays upright at the viewport bottom. */
@media (max-width: 680px) and (orientation: portrait),
       (max-width: 1000px) and (max-height: 680px) and (orientation: landscape),
       (max-height: 680px) and (orientation: landscape) and (pointer: coarse) {
  html, body {
    width: 100%;
    height: 100%;
    overflow: hidden;
  }

  body {
    padding: 0;
    min-height: 0;
  }

  body .deck {
    position: fixed;
    left: 50%;
    top: calc((100vh - var(--deck-nav-height, 68px)) / 2);
    top: calc((100dvh - var(--deck-nav-height, 68px)) / 2);
    width: calc(100vw - 24px);
    width: calc(100dvw - 24px);
    height: calc(100vh - var(--deck-nav-height, 68px) - 24px);
    height: calc(100dvh - var(--deck-nav-height, 68px) - 24px);
    max-width: none;
    gap: 8px;
    transform: translate(-50%, -50%);
  }

  .deck .stage-wrap {
    flex: 1;
    min-height: 0;
    aspect-ratio: auto;
  }

  .deck .slide {
    padding: 18px 24px;
    overflow: auto;
    overscroll-behavior: contain;
  }

  .deck .slide > * { flex-shrink: 0; }
  .deck .body-area { flex: 0 0 auto; min-height: 0; justify-content: flex-start; }
  .deck .diagram { height: auto; }
  .deck .cover { justify-content: flex-start; }
  .deck .cover .mark { width: 40px; height: 40px; margin-bottom: 12px; }
  .deck .cover .meta { margin-top: 16px; }

  /* These grids follow the rotated reading width, not the portrait viewport. */
  .deck .grid2, .deck .grid4, .deck .code-wrap, .deck .cmp { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .deck .grid3, .deck .stat-row { grid-template-columns: repeat(3, minmax(0, 1fr)); }
  .deck .grid4 { grid-template-rows: auto; }
  .deck .code-col { min-width: 0; }
  .deck .code-col pre { flex: none; }
  .deck .edge-zone { display: none; }

  .deck .controls { flex: none; }
  .deck .track { min-width: 0; }
  .deck .nav-btn { width: 44px; height: 44px; }
  .deck .theme-btn { width: auto; }
  .deck .dot-btn { min-width: 44px; min-height: 44px; }

  .deck-navigation-dock {
    position: fixed;
    z-index: 30;
    inset: auto 0 0;
    padding: 10px max(12px, env(safe-area-inset-right)) max(10px, env(safe-area-inset-bottom)) max(12px, env(safe-area-inset-left));
    background: var(--surface);
    border-top: 1px solid var(--line-strong);
    box-shadow: 0 -4px 18px rgba(0, 0, 0, .12);
  }
  .deck-navigation-dock .controls {
    display: grid;
    grid-template-columns: 44px minmax(0, 1fr) 44px 44px;
    gap: 8px;
    padding: 0;
    max-width: 720px;
    margin: auto;
  }
  .deck-navigation-dock .track, .deck-navigation-dock .counter { display: none; }
  .deck-navigation-dock #prevBtn { order: 0; }
  .deck-navigation-dock .deck-slide-selector {
    display: block;
    order: 1;
    width: 100%;
    min-width: 0;
    height: 44px;
    padding: 0 8px;
    border: 1px solid var(--line-strong);
    border-radius: 10px;
    background: var(--surface);
    color: var(--ink);
    font: inherit;
    font-size: 16px;
  }
  .deck-navigation-dock #nextBtn { order: 2; }
  .deck-navigation-dock .nav-btn { width: 44px; height: 44px; }
  .deck-navigation-dock .theme-btn { order: 3; min-width: 44px; padding: 0; font-size: 0; }
  .deck-navigation-dock .theme-btn::after { content: '◐'; font-size: 24px; }
}

@media (max-width: 680px) and (orientation: portrait) {
  body .deck {
    width: calc(100vh - var(--deck-nav-height, 68px) - 24px);
    width: calc(100dvh - var(--deck-nav-height, 68px) - 24px);
    height: calc(100vw - 24px);
    height: calc(100dvw - 24px);
    transform: translate(-50%, -50%) rotate(90deg);
  }
}

@media (min-width: 681px) {
  .deck {
    max-width: min(1220px, calc((100vh - 112px) * 1.72043));
  }
}

@media (max-height: 620px) and (min-width: 681px) {
  body {
    padding-block: 10px;
  }

  .deck {
    gap: 8px;
    max-width: min(1220px, calc((100vh - 84px) * 1.72043));
  }
}