:root {
  color-scheme: dark;
  --bg: #02040a;
  --ink: #e8e8ea;
  --muted: #a1a8b5;
  --line: #252c38;
  --panel: #080c14;
  --panel-2: #0d121c;
  --zeta: #70e0c2;
  --wn: #f0c15a;
  --link: #d9b585;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  min-height: 100%;
  background: var(--bg);
  color: var(--ink);
  font: 16px/1.65 system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans TC", "Microsoft JhengHei", sans-serif;
}

body {
  overflow-x: hidden;
}

button,
input {
  font: inherit;
}

.site-header {
  min-height: 56px;
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 0 22px;
  border-bottom: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.9rem;
}

.brand {
  color: #d9b585;
  font-weight: 700;
  text-decoration: none;
}

.page-shell {
  width: min(1040px, calc(100vw - 32px));
  margin: 0 auto;
  padding: 42px 0 72px;
}

.intro {
  margin-bottom: 34px;
}

.intro p {
  max-width: 760px;
  margin-top: 14px;
  color: #ced8ea;
}

.takeaway {
  max-width: 760px;
  margin-top: 18px;
  padding: 12px 16px;
  border-left: 3px solid var(--muted);
  background: rgba(238, 244, 255, 0.035);
  color: #dce4f2;
  font-size: 1.05rem;
  line-height: 1.6;
}

.eyebrow,
.section-kicker {
  margin: 0 0 8px;
  color: var(--muted);
  font-size: 0.78rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

h1,
h2,
p {
  margin-top: 0;
}

h1 {
  max-width: 820px;
  margin-bottom: 0;
  color: var(--ink);
  font-size: clamp(2rem, 7vw, 4.7rem);
  line-height: 1.04;
  letter-spacing: 0;
}

/* 主題的英文/中文 companion：小一號、次要色，永遠與主題同行不被埋沒 */
.topic-en,
.topic-zh {
  font-size: 0.5em;
  font-weight: 600;
  color: var(--muted);
  letter-spacing: 0.01em;
  white-space: nowrap;
}

/* aha 一句話：副標，重量介於 H1 與內文之間（specificity 蓋過 .intro p）*/
.intro .deck {
  max-width: 760px;
  margin: 16px 0 0;
  color: #d5deee;
  font-size: clamp(1.15rem, 3.2vw, 1.7rem);
  line-height: 1.32;
  font-weight: 400;
}

/* ---- 生活比喻入口（SPEC C7）---- */
.metaphor {
  max-width: 460px;
  margin: 22px 0 0;
}

.metaphor-art {
  display: block;
  width: 100%;
  height: auto;
}

.metaphor figcaption {
  margin-top: 6px;
  color: #ced8ea;
  font-size: 0.95rem;
  line-height: 1.55;
}

.m-ref { stroke: var(--muted); stroke-width: 1; stroke-dasharray: 4 4; }
.m-bounce { fill: none; stroke: var(--zeta); stroke-width: 2.5; }
.m-settle { fill: none; stroke: var(--ink); stroke-width: 2.5; }

/* ---- 步驟鏈（SPEC C7）---- */
.step-no {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 18px;
  height: 18px;
  margin-right: 8px;
  border: 1px solid var(--line);
  border-radius: 50%;
  color: #dce4f2;
}

/* ---- 三重對應色塊（SPEC C6）---- */
.chip {
  display: inline-block;
  width: 11px;
  height: 11px;
  margin-right: 8px;
  border-radius: 3px;
  vertical-align: -1px;
}

.chip-zeta { background: var(--zeta); }
.chip-wn { background: var(--wn); }

/* ---- 四種阻尼個性縮圖列（C7）：一眼看到四種個性長什麼樣，點了直接設 ζ ---- */
.regime-strip {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
  margin-top: 14px;
}

.regime-card {
  display: flex;
  flex-direction: column;
  gap: 4px;
  min-height: 44px;
  padding: 8px;
  border: 1px solid var(--line);
  background: var(--panel-2);
  color: var(--ink);
  text-align: left;
  cursor: pointer;
}

.regime-card svg {
  display: block;
  width: 100%;
  height: auto;
}

.regime-card .rg-ref { stroke: var(--muted); stroke-width: 1; stroke-dasharray: 3 3; }
.regime-card .rg-curve { fill: none; stroke: var(--ink); stroke-width: 2; }

.rg-name { font-weight: 700; font-size: 0.9rem; }
.rg-cond { color: var(--zeta); font-size: 0.78rem; }

.regime-card.is-current { outline: 2px solid var(--zeta); outline-offset: -1px; }
.regime-card:hover { border-color: var(--zeta); }
.regime-card:focus-visible { outline: 2px solid currentColor; outline-offset: 2px; }

.strip-hint {
  margin: 16px 0 8px;
  color: #dce4f2;
  font-size: 0.95rem;
}

.usecase-list {
  display: grid;
  gap: 10px;
  margin: 0;
  padding-left: 1.25rem;
  max-width: 820px;
  color: #ced8ea;
}

.usecase-list b {
  color: var(--ink);
}

@media (max-width: 560px) {
  .regime-strip { grid-template-columns: repeat(2, 1fr); }
}

/* ---- 公式預設收合（SPEC C7）---- */
.formal-details {
  border: 1px solid var(--line);
  background: var(--panel);
}

.formal-details summary {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 14px 16px;
  cursor: pointer;
  list-style: none;
}

.formal-details summary::-webkit-details-marker { display: none; }

.formal-details summary::before {
  content: '▸';
  color: var(--muted);
  font-size: 0.9rem;
  transition: transform 0.15s ease;
}

.formal-details[open] summary::before { transform: rotate(90deg); }

.formal-details summary h2 { margin: 0; }

.summary-hint {
  margin-left: auto;
  color: var(--muted);
  font-size: 0.82rem;
  white-space: nowrap;
}

.details-body { padding: 0 16px 18px; }

@media (prefers-reduced-motion: reduce) {
  .formal-details summary::before { transition: none; }
}

h2 {
  margin-bottom: 10px;
  font-size: 1.18rem;
  line-height: 1.25;
  letter-spacing: 0;
}

.lab-surface {
  padding: 22px;
  border: 1px solid var(--line);
  background: var(--panel);
}

.surface-copy {
  display: flex;
  justify-content: space-between;
  gap: 18px;
  align-items: baseline;
  margin-bottom: 14px;
}

.how-to {
  max-width: 760px;
  margin: 0 0 18px;
  color: var(--muted);
}

.canvas-grid {
  display: grid;
  grid-template-columns: 45% 55%;
  gap: 16px;
  align-items: start;
}

.canvas-col {
  min-width: 0;
}

.canvas-caption {
  margin: 0 0 8px;
  color: var(--muted);
  font-size: 0.82rem;
  line-height: 1.4;
}

.canvas-caption b {
  color: var(--ink);
}

.canvas-wrap {
  width: 100%;
  border: 1px solid #2a3b55;
  background: #04070d;
}

.canvas-wrap.splane {
  aspect-ratio: 1 / 1;
  min-height: 260px;
}

.canvas-wrap.step {
  aspect-ratio: 16 / 9;
  min-height: 220px;
}

canvas {
  display: block;
  width: 100%;
  height: 100%;
}

.controls {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
  margin-top: 16px;
}

.control {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 8px 12px;
  align-items: center;
  min-width: 0;
  padding: 12px;
  border: 1px solid var(--line);
  background: var(--panel-2);
}

.control span,
.control output {
  min-width: 0;
  white-space: nowrap;
}

.control output {
  color: var(--muted);
  font-variant-numeric: tabular-nums;
}

.control input[type="range"] {
  grid-column: 1 / -1;
  width: 100%;
  min-height: 44px; /* 觸控目標 ≥44px（spec §1 手機要求）*/
  accent-color: currentColor;
  touch-action: manipulation;
  cursor: pointer;
}

.control-zeta {
  color: var(--zeta);
}

.control-wn {
  color: var(--wn);
}

.tasks,
.usecases,
.formal,
.links {
  padding-top: 34px;
  margin-top: 34px;
  border-top: 1px solid var(--line);
}

.tasks ol {
  display: grid;
  gap: 10px;
  margin: 0;
  padding-left: 1.25rem;
  color: #d5deee;
}

.formula-group {
  margin: 12px 0 16px;
  padding: 18px 0;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  display: grid;
  gap: 12px;
}

.formal .formula-line {
  margin: 0;
  color: var(--ink);
  font-size: clamp(0.98rem, 2.4vw, 1.4rem);
  line-height: 1.45;
  letter-spacing: 0;
  overflow-wrap: anywhere;
}

.regimes {
  display: grid;
  gap: 8px;
  margin: 14px 0 0;
  padding-left: 1.25rem;
  color: #d5deee;
}

.symbol-gloss {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 8px 14px;
  align-items: center;
  margin: 14px 0 0;
  padding: 0;
}

.symbol-gloss dt {
  margin: 0;
  white-space: nowrap;
}

/* 詞彙表＝鍵盤／輔助科技的正式互動圖例：8 個乾淨 tab 停點，觸控目標 ≥44px */
.symbol-gloss dt[data-sym] {
  display: flex;
  align-items: center;
  min-height: 44px;
  padding: 4px 6px;
  border-radius: 3px;
  cursor: pointer;
}

.symbol-gloss dt[data-sym].is-active {
  outline: 1px solid currentColor;
}

.symbol-gloss dt[data-sym]:focus-visible {
  outline: 2px solid currentColor;
  outline-offset: 2px;
}

.symbol-gloss dd {
  margin: 0;
  color: #ced8ea;
}

.sym {
  font-weight: 700;
}

.sym.zeta {
  color: var(--zeta);
}

.sym.wn {
  color: var(--wn);
}

.sym.muted {
  color: var(--muted);
  font-weight: 400;
}

.sym.envelope {
  color: var(--zeta);
}

.sym.ink {
  color: var(--ink);
}

.formal .sym[data-sym] {
  padding: 0 2px;
  border-radius: 3px;
  cursor: pointer;
}

.formal .sym[data-sym].is-active {
  text-decoration: underline;
  border-radius: 3px;
  outline: 1px solid currentColor;
  padding: 0 2px;
}

.sym-explainer {
  min-height: 1.6em;
  margin: 10px 0 0;
  padding: 10px 12px;
  border: 1px solid var(--line);
  background: var(--panel-2);
  color: #ced8ea;
  font-size: 0.92rem;
  line-height: 1.5;
}

.scope-note {
  max-width: 820px;
  margin: 16px 0 0;
  padding: 12px 14px;
  border-left: 3px solid var(--muted);
  background: rgba(238, 244, 255, 0.035);
  color: #ced8ea;
  line-height: 1.6;
}

.sym-tip {
  position: fixed;
  z-index: 40;
  max-width: 260px;
  padding: 8px 10px;
  border: 1px solid var(--line);
  background: #0a0f18;
  color: var(--ink);
  font-size: 0.85rem;
  line-height: 1.45;
  pointer-events: none;
}

.sym-tip[hidden] {
  display: none;
}

.control.is-cued {
  outline: 1px solid currentColor;
  outline-offset: -1px;
}

.links p,
.formal p {
  max-width: 820px;
  color: #ced8ea;
}

.graph-link {
  display: inline-flex;
  min-height: 44px;
  align-items: center;
  padding: 0 16px;
  border: 1px solid var(--link);
  color: var(--link);
  text-decoration: none;
}

.graph-link:hover {
  background: rgba(217, 181, 133, 0.08);
}

@media (max-width: 760px) {
  .page-shell {
    width: min(100vw - 24px, 640px);
    padding-top: 28px;
  }

  .site-header {
    padding: 0 14px;
  }

  .lab-surface {
    padding: 14px;
  }

  .surface-copy {
    display: block;
  }

  .canvas-grid {
    grid-template-columns: 1fr;
  }

  .controls {
    grid-template-columns: 1fr;
  }

  .control span,
  .control output {
    white-space: normal;
  }
}

/* Minimal visual system: hierarchy comes from type, space, and one hairline. */
body {
  background: var(--bg);
}

.site-header {
  border-bottom-color: var(--line);
  background: transparent;
  backdrop-filter: none;
}

.page-shell {
  width: min(1040px, calc(100vw - 32px));
  padding-top: 42px;
}

.intro {
  display: block;
  margin-bottom: 34px;
  padding: 0;
}

.intro h1,
.intro .deck {
  display: block;
}

.intro h1 {
  max-width: 820px;
  font-size: clamp(2rem, 7vw, 4.4rem);
  letter-spacing: -0.025em;
}

.intro .deck {
  max-width: 760px;
  margin-top: 16px;
}

.intro .metaphor {
  display: block;
  width: auto;
  max-width: 460px;
  margin: 22px 0 0;
  padding: 0;
  border: 0;
  border-radius: 0;
  background: transparent;
  box-shadow: none;
}

.lab-surface {
  overflow: visible;
  padding: 28px 0 0;
  border: 0;
  border-top: 1px solid var(--line);
  border-radius: 0;
  background: transparent;
  box-shadow: none;
}

.surface-copy {
  margin-bottom: 10px;
}

.surface-copy h2 {
  font-size: 1.35rem;
}

.how-to {
  max-width: 760px;
  margin-bottom: 20px;
  padding: 0;
  border: 0;
  border-radius: 0;
  background: transparent;
  color: var(--muted);
}

.canvas-grid {
  grid-template-columns: minmax(280px, 0.86fr) minmax(0, 1.14fr);
  gap: 20px;
}

.canvas-col {
  padding: 0;
  border: 0;
  border-radius: 0;
  background: transparent;
  box-shadow: none;
}

.canvas-caption {
  min-height: 0;
  margin-bottom: 8px;
}

.canvas-wrap {
  border-color: #2a3b55;
  border-radius: 0;
  box-shadow: none;
}

.canvas-wrap.step {
  aspect-ratio: 16 / 10;
}

.controls {
  gap: 20px;
  margin-top: 18px;
}

.control {
  padding: 12px 0 0;
  border: 0;
  border-top: 1px solid var(--line);
  border-radius: 0;
  background: transparent;
}

.strip-hint {
  margin-top: 22px;
  color: var(--muted);
}

.regime-strip {
  gap: 18px;
  margin-top: 8px;
}

.regime-card,
.regime-card:hover,
.regime-card.is-current {
  transform: none;
  padding: 10px 0 0;
  border: 0;
  border-top: 1px solid var(--line);
  border-radius: 0;
  background: transparent;
  box-shadow: none;
}

.regime-card:hover {
  border-top-color: var(--zeta);
}

.regime-card.is-current {
  border-top: 2px solid var(--zeta);
}

@media (max-width: 760px) {
  .page-shell {
    width: min(100vw - 24px, 640px);
    padding-top: 28px;
  }

  .intro h1 {
    font-size: clamp(2.35rem, 12vw, 3.5rem);
  }

  .intro .metaphor {
    padding: 0;
  }

  .lab-surface {
    padding: 26px 0 0;
    border-radius: 0;
  }

  .canvas-grid {
    grid-template-columns: 1fr;
  }

  .canvas-wrap.step {
    aspect-ratio: 16 / 10;
  }
}

/* 2026-07 visual refinement: turn the lab into a composed instrument panel. */
body {
  background:
    radial-gradient(circle at 12% 7%, rgba(112, 224, 194, 0.09), transparent 28rem),
    radial-gradient(circle at 88% 34%, rgba(240, 193, 90, 0.06), transparent 32rem),
    var(--bg);
}

.site-header {
  border-bottom-color: rgba(122, 151, 193, 0.16);
  background: rgba(5, 7, 13, 0.72);
  backdrop-filter: blur(14px);
}

.page-shell {
  width: min(1120px, calc(100vw - 40px));
  padding-top: 34px;
}

.intro {
  display: grid;
  grid-template-columns: minmax(0, 1.25fr) minmax(300px, 0.75fr);
  grid-template-rows: auto auto;
  column-gap: clamp(28px, 5vw, 72px);
  align-items: center;
  margin-bottom: 30px;
  padding: 18px 0 8px;
}

.intro h1,
.intro .deck {
  grid-column: 1;
}

.intro h1 {
  font-size: clamp(2.8rem, 5.3vw, 4.5rem);
  letter-spacing: -0.045em;
}

.intro .deck {
  margin-top: 12px;
  font-size: clamp(1.12rem, 2vw, 1.48rem);
}

.intro .metaphor {
  grid-column: 2;
  grid-row: 1 / 3;
  width: 100%;
  max-width: none;
  margin: 0;
  padding: 18px 20px 14px;
  border: 1px solid rgba(112, 224, 194, 0.2);
  border-radius: 20px;
  background: linear-gradient(145deg, rgba(18, 27, 41, 0.86), rgba(8, 13, 22, 0.72));
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.24), inset 0 1px rgba(255, 255, 255, 0.03);
}

.intro .metaphor figcaption {
  margin: 4px 0 0;
  color: #b9c6da;
}

.lab-surface {
  position: relative;
  overflow: hidden;
  padding: 28px;
  border-color: rgba(112, 224, 194, 0.2);
  border-radius: 28px;
  background:
    radial-gradient(circle at 14% 0%, rgba(112, 224, 194, 0.08), transparent 26rem),
    linear-gradient(155deg, rgba(14, 23, 37, 0.98), rgba(8, 13, 22, 0.98));
  box-shadow: 0 28px 80px rgba(0, 0, 0, 0.32), inset 0 1px rgba(255, 255, 255, 0.04);
}

.surface-copy {
  display: block;
  margin-bottom: 12px;
}

.surface-copy h2 {
  margin: 0;
  font-size: clamp(1.35rem, 2vw, 1.7rem);
}

.how-to {
  max-width: none;
  margin-bottom: 20px;
  padding: 11px 14px;
  border-left: 2px solid var(--zeta);
  border-radius: 0 10px 10px 0;
  background: rgba(112, 224, 194, 0.055);
  color: #bdc9da;
}

.canvas-grid {
  grid-template-columns: minmax(300px, 0.88fr) minmax(0, 1.3fr);
  gap: 18px;
}

.canvas-col {
  padding: 14px;
  border: 1px solid rgba(80, 105, 142, 0.32);
  border-radius: 18px;
  background: rgba(4, 8, 15, 0.52);
  box-shadow: inset 0 1px rgba(255, 255, 255, 0.025);
}

.canvas-caption {
  min-height: 2.8em;
  margin-bottom: 10px;
  color: #94a5bd;
}

.canvas-wrap {
  overflow: hidden;
  border-color: rgba(92, 121, 163, 0.42);
  border-radius: 13px;
  background: #060b13;
  box-shadow: inset 0 0 36px rgba(0, 0, 0, 0.34);
}

.canvas-wrap.step {
  aspect-ratio: 1.42 / 1;
}

.controls {
  gap: 12px;
  margin-top: 18px;
}

.control {
  padding: 14px 16px;
  border-color: rgba(80, 105, 142, 0.34);
  border-radius: 14px;
  background: linear-gradient(135deg, rgba(20, 31, 47, 0.92), rgba(13, 21, 34, 0.92));
}

.regime-strip {
  gap: 12px;
}

.regime-card {
  padding: 10px;
  border-color: rgba(80, 105, 142, 0.3);
  border-radius: 14px;
  background: linear-gradient(145deg, rgba(18, 28, 43, 0.9), rgba(11, 18, 29, 0.9));
  transition: transform 150ms ease, border-color 150ms ease, background 150ms ease;
}

.regime-card:hover {
  transform: translateY(-2px);
  background: rgba(24, 39, 59, 0.95);
}

.regime-card.is-current {
  outline: none;
  border-color: var(--zeta);
  background: linear-gradient(145deg, rgba(112, 224, 194, 0.14), rgba(14, 27, 38, 0.95));
  box-shadow: 0 10px 28px rgba(27, 96, 83, 0.16);
}

.formal-details {
  overflow: hidden;
  border-radius: 16px;
}

@media (max-width: 760px) {
  .page-shell {
    width: min(100vw - 24px, 640px);
  }

  .intro {
    display: block;
    padding-top: 6px;
  }

  .intro h1 {
    font-size: clamp(2.45rem, 12vw, 3.5rem);
  }

  .intro .metaphor {
    margin-top: 20px;
  }

  .lab-surface {
    padding: 16px;
    border-radius: 20px;
  }

  .canvas-grid {
    grid-template-columns: 1fr;
  }

  .canvas-caption {
    min-height: 0;
  }

  .canvas-wrap.step {
    aspect-ratio: 16 / 10;
  }
}

/* Final cascade: minimal Depth layout, shared in spirit with sine-wave. */
body { background: var(--bg); }
.site-header { border-bottom-color: var(--line); background: transparent; backdrop-filter: none; }
.page-shell { width: min(1040px, calc(100vw - 32px)); padding-top: 42px; }
.intro { display: block; margin-bottom: 34px; padding: 0; }
.intro h1,
.intro .deck { display: block; }
.intro h1 { max-width: 820px; font-size: clamp(2rem, 7vw, 4.4rem); letter-spacing: -0.025em; }
.intro .deck { max-width: 760px; margin-top: 16px; }
.intro .metaphor {
  display: block;
  width: auto;
  max-width: 460px;
  margin: 22px 0 0;
  padding: 0;
  border: 0;
  border-radius: 0;
  background: transparent;
  box-shadow: none;
}
.lab-surface {
  overflow: visible;
  padding: 28px 0 0;
  border: 0;
  border-top: 1px solid var(--line);
  border-radius: 0;
  background: transparent;
  box-shadow: none;
}
.surface-copy { margin-bottom: 10px; }
.surface-copy h2 { font-size: 1.35rem; }
.how-to {
  max-width: 760px;
  margin-bottom: 20px;
  padding: 0;
  border: 0;
  border-radius: 0;
  background: transparent;
  color: var(--muted);
}
.canvas-grid { grid-template-columns: minmax(280px, 0.86fr) minmax(0, 1.14fr); gap: 20px; }
.canvas-col { padding: 0; border: 0; border-radius: 0; background: transparent; box-shadow: none; }
.canvas-caption { min-height: 0; margin-bottom: 8px; }
.canvas-wrap { border-color: #2a3b55; border-radius: 0; box-shadow: none; }
.canvas-wrap.step { aspect-ratio: 16 / 10; }
.controls { gap: 20px; margin-top: 18px; }
.control { padding: 12px 0 0; border: 0; border-top: 1px solid var(--line); border-radius: 0; background: transparent; }
.strip-hint { margin-top: 22px; color: var(--muted); }
.regime-strip { gap: 18px; margin-top: 8px; }
.regime-card,
.regime-card:hover,
.regime-card.is-current {
  transform: none;
  padding: 10px 0 0;
  border: 0;
  border-top: 1px solid var(--line);
  border-radius: 0;
  background: transparent;
  box-shadow: none;
}
.regime-card:hover { border-top-color: var(--zeta); }
.regime-card.is-current { border-top: 2px solid var(--zeta); }

/* Readable equivalents sit next to the controls in every visual/motion mode. */
.response-reading { margin: 22px 0; max-width: 760px; }
.response-reading h3 { margin: 0 0 6px; font-size: 1.05rem; }
.response-reading p { margin: 8px 0; }
.response-values { display: grid; grid-template-columns: 4em minmax(0, 1fr); gap: 6px 12px; margin: 12px 0; }
.response-values dt { color: var(--muted); }
.response-values dd { margin: 0; font-variant-numeric: tabular-nums; }
#response-window, .motion-note { color: var(--muted); font-size: .93rem; }
.rg-current { visibility: hidden; font-size: .8rem; font-weight: 400; }
.regime-card.is-current .rg-current { visibility: visible; }
.reduced-motion-note { display: none; }
.static-regimes { padding-left: 1.4em; }
.static-regimes li { margin: 6px 0; }
@media (prefers-reduced-motion: reduce) {
  .standard-motion-note { display: none; }
  .reduced-motion-note { display: inline; }
}

@media (max-width: 760px) {
  .page-shell { width: min(100vw - 24px, 640px); padding-top: 28px; }
  .intro h1 { font-size: clamp(2.35rem, 12vw, 3.5rem); }
  .intro .metaphor { padding: 0; }
  .lab-surface { padding: 26px 0 0; border-radius: 0; }
  .canvas-grid { grid-template-columns: 1fr; }
  .canvas-wrap.step { aspect-ratio: 16 / 10; }
}

/* Quiet reading rhythm shared across Depth; diagrams retain their own scales. */
.site-header{padding-inline:max(24px,calc((100vw - 1040px)/2));gap:16px;border-bottom-color:rgba(161,168,181,.12)}
.brand{letter-spacing:.035em;font-size:.95rem}
.site-header>span{font-size:.75rem;letter-spacing:.1em;color:var(--muted)}
.page-shell,body>main{padding-top:52px}
h1{font-size:clamp(40px,7vw,75px);font-weight:650;text-wrap:balance}
.topic-en,.topic-zh{display:block;margin:12px 0 0;font-size:clamp(18px,2.2vw,25px);font-weight:400;line-height:1.4;white-space:normal}
h2{font-weight:600;line-height:1.45;text-wrap:balance}
p,li{line-height:1.8}
.deck{line-height:1.55;max-width:38em;color:#d8d9dd}
.intro{margin-bottom:40px}
.tasks,.usecases,.formal,.links{margin-top:48px;padding-top:32px}
.tasks ol,.usecase-list{gap:16px;max-width:70ch}
.details-body,.formal-body{max-width:78ch}
.formal-details{border-color:rgba(161,168,181,.18);background:var(--panel)}
.formal-details summary{min-height:60px;padding:16px 20px}
.formal-details summary:hover{background:rgba(217, 181, 133,.035)}
.canvas-wrap{border-color:rgba(161,168,181,.22)}
.control{padding:16px 12px 4px;background:var(--panel);border-top-color:rgba(161,168,181,.18)}
.control-row{padding:16px 18px 10px;background:var(--panel);border-top-color:rgba(161,168,181,.18)}
button:focus-visible,a:focus-visible,summary:focus-visible,input:focus-visible{outline:2px solid #d9b585;outline-offset:4px}
a{ text-underline-offset:.25em }
@media(max-width:760px){
 .site-header{padding-inline:20px}
 .page-shell,body>main{width:calc(100% - 40px);padding-top:32px}
 h1{overflow-wrap:break-word}
 .deck{font-size:1.12rem;line-height:1.65}
 .topic-en,.topic-zh{font-size:20px;line-height:1.4}
 .controls{display:grid;grid-template-columns:minmax(0,1fr);gap:12px;overflow:visible}
 .control{width:100%;min-width:0}
 .control input{min-width:0}
 .control{padding-inline:8px}
 .tasks,.usecases,.formal,.links{margin-top:36px;padding-top:28px}
 .summary-hint{white-space:normal;text-align:right}
}