:root {
  --bg: #0a0a14;
  --surface: #14141f;
  --surface-2: #1d1d2c;
  --line: #2a2a3d;
  --line-soft: #1c1c2c;
  --text: #ece6d9;
  --muted: #968fa3;
  --dim: #5d586c;

  --parallel: #5b8df0;
  --parallel-glow: rgba(91, 141, 240, 0.32);
  --era: #e8a14a;
  --rose: #d97594;
  --mortality: #8a6ca8;
  --gold: #d4b95e;
  --fate: #5fbf99;

  --primary: var(--parallel);
  --primary-glow: var(--parallel-glow);

  --display: 'Spectral', 'Noto Serif SC', serif;
  --body: 'Karla', system-ui, sans-serif;
  --mono: 'JetBrains Mono', monospace;
  --cjk-display: 'Noto Serif SC', serif;
  --cjk-body: 'Noto Sans SC', sans-serif;
}

[data-theme="light"] {
  --bg: #f5f1e8;
  --surface: #ffffff;
  --surface-2: #ece5d2;
  --line: #cdc4b0;
  --line-soft: #e0d8c6;
  --text: #1d1a16;
  --muted: #635c4f;
  --dim: #9d9484;

  --parallel: #2c5cb8;
  --parallel-glow: rgba(44, 92, 184, 0.16);
  --era: #b87a26;
  --rose: #b54870;
  --mortality: #5d4480;
  --gold: #9c8328;
  --fate: #2c8a6a;

  --primary: var(--parallel);
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body { background: var(--bg); color: var(--text); font-family: var(--body); -webkit-font-smoothing: antialiased; line-height: 1.6; overflow-x: hidden; }

html[data-lang="en"] [lang="zh"] { display: none; }
html[data-lang="zh"] [lang="en"] { display: none; }
html[data-lang="zh"] body { font-family: var(--cjk-body); }
html[data-lang="zh"] h1, html[data-lang="zh"] h2, html[data-lang="zh"] h3, html[data-lang="zh"] .display { font-family: var(--cjk-display); }

a { color: inherit; text-decoration: none; }
a:hover { color: var(--parallel); }

.wrap { max-width: 1180px; margin: 0 auto; padding: 0 24px; }

.nav { position: sticky; top: 0; z-index: 50; background: color-mix(in srgb, var(--bg) 85%, transparent); backdrop-filter: blur(14px); border-bottom: 1px solid var(--line-soft); }
.nav-inner { display: flex; align-items: center; gap: 28px; padding: 14px 24px; max-width: 1180px; margin: 0 auto; }
.brand { display: flex; align-items: center; gap: 10px; font-family: var(--display); font-weight: 600; }
.brand-mark { width: 30px; height: 30px; border-radius: 4px; background: linear-gradient(135deg, var(--parallel), var(--mortality), var(--era)); position: relative; overflow: hidden; }
.brand-mark::after { content: ''; position: absolute; inset: 4px; background: var(--bg); border-radius: 2px; }
.brand-mark::before { content: ''; position: absolute; left: 9px; right: 9px; top: 8px; bottom: 8px; background: linear-gradient(135deg, var(--parallel), var(--era)); z-index: 1; clip-path: polygon(0 50%, 50% 0, 100% 50%, 50% 100%); }
.brand-name { font-size: 19px; letter-spacing: 0.01em; }
.nav-links { display: flex; gap: 18px; margin-left: auto; font-size: 13px; color: var(--muted); }
.nav-links a:hover { color: var(--text); }
.nav-ctrl { display: flex; gap: 6px; }
.btn { font-family: var(--mono); font-size: 11px; letter-spacing: 0.06em; padding: 7px 12px; background: transparent; color: var(--muted); border: 1px solid var(--line); border-radius: 6px; cursor: pointer; transition: all 0.15s; }
.btn:hover { color: var(--text); border-color: var(--parallel); }

.hero { position: relative; padding: 100px 0 80px; overflow: hidden; }
.hero::before { content: ''; position: absolute; inset: 0; background: radial-gradient(50% 35% at 25% 35%, var(--parallel-glow), transparent 70%), radial-gradient(45% 30% at 80% 60%, rgba(232, 161, 74, 0.22), transparent 70%); opacity: 0.55; filter: blur(50px); pointer-events: none; }
[data-theme="light"] .hero::before { opacity: 0.22; }

.hero-grid { position: relative; display: grid; grid-template-columns: 1fr 1fr; gap: 56px; align-items: center; }
@media (max-width: 880px) { .hero-grid { grid-template-columns: 1fr; gap: 40px; } }

.eyebrow { font-family: var(--mono); font-size: 11px; letter-spacing: 0.18em; color: var(--muted); text-transform: uppercase; margin-bottom: 22px; }
h1.display { font-family: var(--display); font-weight: 500; font-size: clamp(38px, 5.5vw, 68px); line-height: 1.06; letter-spacing: -0.014em; margin: 0 0 22px; }
h1.display em { font-style: italic; color: var(--parallel); font-weight: 400; }
.lede { font-size: 17px; color: var(--muted); max-width: 56ch; margin: 0 0 28px; }
.tags { display: flex; gap: 8px; flex-wrap: wrap; }
.tag { font-family: var(--mono); font-size: 11px; letter-spacing: 0.08em; color: var(--muted); border: 1px solid var(--line); padding: 5px 10px; border-radius: 100px; }

.timeline-viz { position: relative; aspect-ratio: 1 / 1; max-width: 520px; margin: 0 auto; }
.timeline-viz svg { width: 100%; height: 100%; }

section { padding: 80px 0; border-top: 1px solid var(--line-soft); position: relative; }
.sec-head { margin-bottom: 44px; }
.sec-tag { font-family: var(--mono); font-size: 11px; letter-spacing: 0.16em; color: var(--parallel); text-transform: uppercase; margin-bottom: 14px; }
h2 { font-family: var(--display); font-weight: 500; font-size: clamp(30px, 3.6vw, 44px); line-height: 1.12; letter-spacing: -0.012em; margin: 0 0 14px; max-width: 22ch; }
h2 em { font-style: italic; color: var(--parallel); font-weight: 400; }
.sec-lede { color: var(--muted); max-width: 66ch; font-size: 16px; }

.grid { display: grid; gap: 18px; }
.grid.c2 { grid-template-columns: repeat(2, 1fr); }
.grid.c3 { grid-template-columns: repeat(3, 1fr); }
.grid.c5 { grid-template-columns: repeat(5, 1fr); }
@media (max-width: 880px) { .grid.c2, .grid.c3, .grid.c5 { grid-template-columns: 1fr; } }

.card { background: var(--surface); border: 1px solid var(--line); border-radius: 12px; padding: 22px; transition: border-color 0.2s, transform 0.2s; }
.card:hover { border-color: var(--parallel); transform: translateY(-2px); }
.card.glow-parallel { border-left: 3px solid var(--parallel); }
.card.glow-era { border-left: 3px solid var(--era); }
.card.glow-rose { border-left: 3px solid var(--rose); }
.card.glow-mortality { border-left: 3px solid var(--mortality); }
.card.glow-gold { border-left: 3px solid var(--gold); }
.card.glow-fate { border-left: 3px solid var(--fate); }
.card-tag { font-family: var(--mono); font-size: 10px; letter-spacing: 0.1em; text-transform: uppercase; color: var(--muted); margin-bottom: 10px; }
.card h3 { font-family: var(--display); font-weight: 500; font-size: 19px; margin: 0 0 10px; line-height: 1.25; }
.card p { color: var(--muted); font-size: 14px; margin: 0 0 8px; }
.card .meta { font-family: var(--mono); font-size: 11px; color: var(--dim); margin-top: 14px; border-top: 1px dashed var(--line); padding-top: 12px; }

.sim-lab { background: var(--surface); border: 1px solid var(--line); border-radius: 16px; padding: 28px; }
.sim-lab .controls { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; margin-bottom: 24px; }
@media (max-width: 880px) { .sim-lab .controls { grid-template-columns: 1fr; } }
.sim-lab label { font-family: var(--mono); font-size: 11px; letter-spacing: 0.08em; color: var(--muted); text-transform: uppercase; display: block; margin-bottom: 6px; }
.sim-lab select, .sim-lab input { width: 100%; background: var(--surface-2); color: var(--text); border: 1px solid var(--line); border-radius: 6px; padding: 10px; font-family: var(--body); font-size: 14px; }
.sim-lab button.go { background: var(--parallel); color: #07091a; border: 0; padding: 12px 26px; border-radius: 8px; font-family: var(--mono); font-size: 12px; letter-spacing: 0.08em; cursor: pointer; font-weight: 700; }
.sim-out { margin-top: 24px; padding: 24px 28px; background: var(--surface-2); border-left: 3px solid var(--parallel); border-radius: 6px; line-height: 1.7; min-height: 100px; color: var(--text); }
.sim-out:empty::before { content: 'Pick an era and a place. Press Run.'; color: var(--dim); font-style: italic; }
html[data-lang="zh"] .sim-out:empty::before { content: '挑一个年代和一个地点。点运行。'; }
.sim-out h4 { font-family: var(--display); font-style: italic; font-size: 18px; margin: 0 0 6px; color: var(--parallel); }
.sim-out .dim { font-family: var(--mono); font-size: 10px; letter-spacing: 0.12em; text-transform: uppercase; color: var(--muted); margin-top: 14px; margin-bottom: 4px; }
.sim-out p { margin: 4px 0 12px; font-size: 15px; }

.mirror-wrap { background: var(--surface); border: 1px solid var(--line); border-radius: 16px; padding: 28px; }
.prompt-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 10px; margin-bottom: 18px; }
.prompt-btn { background: var(--surface-2); border: 1px solid var(--line); color: var(--text); text-align: left; padding: 14px 16px; border-radius: 10px; cursor: pointer; font-family: var(--body); font-size: 13px; transition: all 0.18s; }
.prompt-btn:hover { border-color: var(--parallel); transform: translateY(-1px); }
.prompt-btn .pt-tag { font-family: var(--mono); font-size: 10px; letter-spacing: 0.1em; color: var(--parallel); text-transform: uppercase; display: block; margin-bottom: 6px; }
.prompt-btn strong { font-family: var(--display); font-size: 15px; }
.mirror-input { display: flex; gap: 10px; margin-bottom: 16px; }
.mirror-input textarea { flex: 1; background: var(--surface-2); border: 1px solid var(--line); border-radius: 8px; padding: 12px; font-family: var(--body); font-size: 14px; color: var(--text); resize: vertical; min-height: 70px; }
.mirror-input textarea:focus { outline: none; border-color: var(--parallel); }
.mirror-input button { background: var(--parallel); color: #07091a; border: 0; border-radius: 8px; padding: 0 26px; font-family: var(--mono); font-size: 12px; letter-spacing: 0.08em; cursor: pointer; font-weight: 700; }
.mirror-out { background: var(--surface-2); border-left: 3px solid var(--parallel); border-radius: 6px; padding: 22px 24px; font-size: 15px; line-height: 1.7; white-space: pre-wrap; min-height: 80px; color: var(--text); }
.mirror-out:empty::before { content: 'Pick a probe above or describe a counterfactual.'; color: var(--dim); font-style: italic; }
html[data-lang="zh"] .mirror-out:empty::before { content: '从上方选择一个探针，或描述一个反事实。'; }

.rails { background: var(--surface); border: 1px solid var(--line); border-left: 3px solid var(--rose); border-radius: 14px; padding: 26px 28px; }
.rails h3 { font-family: var(--display); margin: 0 0 14px; font-size: 20px; color: var(--rose); }
.rails ul { margin: 0; padding-left: 20px; color: var(--muted); font-size: 14.5px; }
.rails li { margin-bottom: 10px; }

footer { border-top: 1px solid var(--line-soft); padding: 40px 24px; color: var(--muted); font-size: 13px; text-align: center; }
footer a { color: var(--muted); border-bottom: 1px dotted var(--line); }
footer a:hover { color: var(--parallel); }