:root {
  --main: #faf9f6; --sidebar: #efeeea; --raised: #ffffff; --track: #e9e8e3;
  --line: #ddded8; --ink: #202622; --secondary: #5d655f; --tertiary: #626a64;
  --accent: #426650; --accent-hover: #365940; --on-accent: #ffffff;
  --mark: #426650; --mark-lines: #a3bea4; --selected: #e0e7de; --playing: #eef2ec;
  --warning: #8a6429;
  --shadow: 0 1px 2px rgba(32,38,34,.06), 0 12px 40px -12px rgba(32,38,34,.22);
  --radius: 14px;
  --font: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", system-ui, sans-serif;
  --mono: ui-monospace, "SF Mono", "JetBrains Mono", Menlo, Consolas, monospace;
  color-scheme: light dark;
}
@media (prefers-color-scheme: dark) {
  :root {
    --main: #222623; --sidebar: #1b1f1c; --raised: #2b312c; --track: #1b1f1c;
    --line: #3b433c; --ink: #f1f3ee; --secondary: #b5bdb3; --tertiary: #9ba59a;
    --accent: #abc4ad; --accent-hover: #bbd0bd; --on-accent: #19221c;
    --mark: #abc4ad; --mark-lines: #5d7a63; --selected: #344538; --playing: #2d3b30;
    --warning: #d1b06f;
    --shadow: 0 1px 2px rgba(0,0,0,.3), 0 18px 50px -12px rgba(0,0,0,.6);
  }
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } *, *::before, *::after { animation: none !important; transition: none !important; } }
body { margin: 0; background: var(--main); color: var(--ink); font: 16px/1.6 var(--font); -webkit-font-smoothing: antialiased; }
a { color: inherit; }
code { font-family: var(--mono); font-size: .88em; }
.wrap { max-width: 1160px; margin: 0 auto; padding: 0 24px; }
.skip { position: absolute; left: -999px; } .skip:focus { left: 16px; top: 16px; z-index: 100; background: var(--raised); padding: 8px 12px; border-radius: 8px; }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; border-radius: 6px; }

/* Mark */
.mark { width: 34px; height: auto; }
.mark .m-vee { stroke: var(--mark); } .mark .m-lines { stroke: var(--mark-lines); }
.mark.big { width: 84px; margin-bottom: 18px; }

/* Nav */
.nav { position: sticky; top: 0; z-index: 50; backdrop-filter: saturate(160%) blur(14px); -webkit-backdrop-filter: saturate(160%) blur(14px); background: color-mix(in srgb, var(--main) 82%, transparent); border-bottom: 1px solid color-mix(in srgb, var(--line) 70%, transparent); }
.nav-inner { display: flex; align-items: center; gap: 24px; height: 64px; }
.brand { display: flex; align-items: center; gap: 10px; text-decoration: none; font-weight: 650; font-size: 18px; letter-spacing: -.01em; }
.links { display: flex; gap: 22px; margin-left: 12px; }
.links a { text-decoration: none; color: var(--secondary); font-size: 14.5px; }
.links a:hover { color: var(--ink); }
.nav-actions { margin-left: auto; display: flex; gap: 10px; align-items: center; }
.lang { font: inherit; font-size: 13.5px; color: var(--secondary); background: transparent; border: 1px solid var(--line); border-radius: 999px; padding: 5px 12px; cursor: pointer; }
.lang:hover { color: var(--ink); border-color: var(--tertiary); }

/* Buttons */
.btn { display: inline-flex; align-items: center; gap: 9px; text-decoration: none; font-weight: 600; font-size: 15.5px; border-radius: 11px; padding: 12px 20px; transition: background .15s, transform .15s, border-color .15s; border: 1px solid transparent; }
.btn svg { width: 18px; height: 18px; }
.btn:active { transform: translateY(1px); }
.btn-primary { background: var(--accent); color: var(--on-accent); }
.btn-primary:hover { background: var(--accent-hover); }
.btn-secondary { background: var(--raised); border-color: var(--line); }
.btn-secondary:hover { border-color: var(--tertiary); }
.btn-secondary svg { color: #d1a03a; }
.btn-ghost { border-color: var(--line); }
.btn-ghost:hover { border-color: var(--tertiary); }
.btn-small { padding: 6px 12px; font-size: 13.5px; border-radius: 9px; }
.btn-small svg { width: 15px; height: 15px; }

/* Hero */
.hero { padding: 72px 0 56px; position: relative; overflow: hidden; }
.hero::before { content: ""; position: absolute; inset: -20% -10% auto auto; width: 720px; height: 720px; background: radial-gradient(closest-side, color-mix(in srgb, var(--mark-lines) 38%, transparent), transparent); filter: blur(10px); pointer-events: none; }
.hero-grid { display: grid; grid-template-columns: 1fr 1.15fr; gap: 56px; align-items: center; position: relative; }
.eyebrow { display: inline-flex; align-items: center; gap: 8px; font-size: 13.5px; color: var(--secondary); background: var(--raised); border: 1px solid var(--line); padding: 5px 12px; border-radius: 999px; margin: 0 0 22px; }
.dot { width: 7px; height: 7px; border-radius: 50%; background: var(--accent); box-shadow: 0 0 0 4px color-mix(in srgb, var(--accent) 20%, transparent); }
h1 { font-size: clamp(38px, 5.2vw, 62px); line-height: 1.06; letter-spacing: -.035em; margin: 0 0 20px; font-weight: 720; }
h1 em { font-style: normal; color: var(--accent); }
.lede { font-size: 18.5px; color: var(--secondary); margin: 0 0 30px; max-width: 34em; }
.cta { display: flex; flex-wrap: wrap; gap: 12px; }
.cta.center { justify-content: center; }
.soon { margin: 22px 0 0; color: var(--tertiary); font-size: 14px; display: flex; gap: 10px; align-items: baseline; flex-wrap: wrap; }
.pill { font-size: 11.5px; font-weight: 650; letter-spacing: .04em; text-transform: uppercase; color: var(--warning); border: 1px solid color-mix(in srgb, var(--warning) 45%, transparent); padding: 2px 8px; border-radius: 999px; white-space: nowrap; }

/* Window illustration */
.window-wrap { margin: 0; }
.window { display: grid; grid-template-columns: 210px 1fr; min-height: 420px; background: var(--main); border: 1px solid var(--line); border-radius: 16px; overflow: hidden; box-shadow: var(--shadow); font-size: 13px; transform: perspective(1600px) rotateY(-4deg) rotateX(2deg); transition: transform .6s cubic-bezier(.2,.7,.2,1); }
.window:hover { transform: none; }
.win-side { background: var(--sidebar); border-right: 1px solid var(--line); padding: 14px 10px 10px; display: flex; flex-direction: column; }
.traffic { display: flex; gap: 7px; margin: 2px 4px 16px; } .traffic i { width: 11px; height: 11px; border-radius: 50%; background: #ec6a5e; } .traffic i:nth-child(2) { background: #f4bf4f; } .traffic i:nth-child(3) { background: #61c554; }
.side-title { font-weight: 650; font-size: 13px; margin: 0 6px 8px; }
.group-label { font-size: 11px; color: var(--tertiary); margin: 10px 6px 4px; }
.row { padding: 7px 8px; border-radius: 8px; }
.row.selected { background: var(--selected); }
.row-name { font-weight: 550; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.row-meta { color: var(--tertiary); font-size: 11.5px; display: flex; align-items: center; gap: 6px; }
.bar { flex: 1; height: 4px; border-radius: 4px; background: var(--track); overflow: hidden; } .bar span { display: block; height: 100%; background: var(--accent); border-radius: 4px; animation: grow 6s ease-in-out infinite alternate; }
@keyframes grow { from { width: 48%; } to { width: 70%; } }
.tag { font-weight: 600; font-size: 10.5px; padding: 0 5px; border-radius: 4px; border: 1px solid var(--line); color: var(--secondary); }
.side-foot { margin-top: auto; padding-top: 12px; border-top: 1px solid var(--line); }
.model-btn { font-size: 11.5px; color: var(--secondary); }
.win-main { padding: 18px 20px; display: flex; flex-direction: column; min-width: 0; }
.main-head { display: flex; justify-content: space-between; align-items: flex-start; gap: 12px; padding-bottom: 12px; border-bottom: 1px solid var(--line); margin-bottom: 8px; }
.file { font-weight: 650; font-size: 15px; }
.sub { color: var(--tertiary); font-size: 11.5px; font-variant-numeric: tabular-nums; }
.seg-pill { display: flex; background: var(--track); border-radius: 8px; padding: 2px; font-size: 11.5px; flex-shrink: 0; }
.seg-pill span { padding: 3px 9px; border-radius: 6px; color: var(--secondary); }
.seg-pill .on { background: var(--raised); color: var(--ink); box-shadow: 0 1px 2px rgba(0,0,0,.08); }
.segments { list-style: none; margin: 0; padding: 0; }
.segments li { display: grid; grid-template-columns: 64px 1fr auto; gap: 10px; align-items: baseline; padding: 8px 8px; border-radius: 8px; }
.segments li.playing { background: var(--playing); }
.segments time { font-family: var(--mono); font-size: 11.5px; color: var(--tertiary); }
.segments p { margin: 0; line-height: 1.5; }
.lang-chip { font-family: var(--mono); font-size: 10px; color: var(--accent); border: 1px solid color-mix(in srgb, var(--accent) 35%, transparent); border-radius: 4px; padding: 0 4px; }
.lang-chip.en { color: var(--warning); border-color: color-mix(in srgb, var(--warning) 40%, transparent); }
.writing p { color: var(--secondary); }
.caret { display: inline-block; width: 2px; height: 1em; background: var(--accent); margin-left: 2px; vertical-align: -2px; animation: blink 1s steps(1) infinite; }
@keyframes blink { 50% { opacity: 0; } }
figcaption { margin-top: 14px; font-size: 12.5px; color: var(--tertiary); text-align: center; }

/* Facts */
.facts { border-block: 1px solid var(--line); background: var(--sidebar); }
.facts-grid { display: grid; grid-template-columns: repeat(4, 1fr); }
.facts-grid div { padding: 22px 18px; display: flex; flex-direction: column; gap: 2px; border-left: 1px solid var(--line); }
.facts-grid div:first-child { border-left: 0; }
.facts-grid strong { font-size: 16.5px; letter-spacing: -.01em; }
.facts-grid span { font-size: 13.5px; color: var(--tertiary); }

/* Sections */
.section { padding: 96px 0; }
.section.alt { background: var(--sidebar); border-block: 1px solid var(--line); }
.sec-head { max-width: 720px; margin-bottom: 44px; }
.kicker { color: var(--accent); font-weight: 650; font-size: 13.5px; letter-spacing: .06em; text-transform: uppercase; margin: 0 0 10px; }
h2 { font-size: clamp(28px, 3.4vw, 40px); line-height: 1.15; letter-spacing: -.025em; margin: 0 0 14px; font-weight: 700; }
.sec-head p:not(.kicker), .split p { color: var(--secondary); font-size: 17px; margin: 0 0 14px; }
.cards { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; }
.card { background: var(--raised); border: 1px solid var(--line); border-radius: var(--radius); padding: 22px; transition: transform .2s, box-shadow .2s, border-color .2s; }
.card:hover { transform: translateY(-3px); box-shadow: var(--shadow); border-color: color-mix(in srgb, var(--accent) 35%, var(--line)); }
.card h3 { font-size: 16.5px; margin: 14px 0 6px; letter-spacing: -.01em; }
.card p { margin: 0; color: var(--secondary); font-size: 14.5px; line-height: 1.55; }
.ico { width: 40px; height: 40px; border-radius: 10px; display: grid; place-items: center; background: var(--selected); }
.ico svg { width: 21px; height: 21px; fill: none; stroke: var(--accent); stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; }

.split { display: grid; grid-template-columns: 1fr 1fr; gap: 56px; align-items: center; }
.textlink { color: var(--accent); font-weight: 600; text-decoration: none; }
.textlink:hover { text-decoration: underline; }
.md-card, .term { background: var(--raised); border: 1px solid var(--line); border-radius: var(--radius); box-shadow: var(--shadow); overflow: hidden; }
.md-head { display: flex; justify-content: space-between; padding: 10px 16px; border-bottom: 1px solid var(--line); font-size: 13px; font-weight: 600; }
.muted { color: var(--tertiary); font-weight: 400; }
pre { margin: 0; padding: 18px 20px; overflow-x: auto; font: 13.5px/1.7 var(--mono); white-space: pre; }
.md-card pre { white-space: pre-wrap; }
pre .t { color: var(--accent); }
pre .c { color: var(--tertiary); }

.pipeline { list-style: none; margin: 0; padding: 0; display: grid; grid-template-columns: repeat(5, 1fr); gap: 14px; counter-reset: s; position: relative; }
.pipeline li { position: relative; background: var(--raised); border: 1px solid var(--line); border-radius: var(--radius); padding: 22px 18px; }
.pipeline li:not(:last-child)::after { content: ""; position: absolute; top: 38px; right: -14px; width: 14px; height: 2px; background: var(--mark-lines); }
.pipeline .n { display: inline-grid; place-items: center; width: 32px; height: 32px; border-radius: 50%; background: var(--accent); color: var(--on-accent); font-weight: 700; font-size: 14px; }
.pipeline h3 { font-size: 16px; margin: 12px 0 6px; }
.pipeline p { margin: 0; color: var(--secondary); font-size: 14px; line-height: 1.55; }

.models { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; }
.model { background: var(--raised); border: 1px solid var(--line); border-radius: var(--radius); padding: 26px; }
.model-top { display: flex; justify-content: space-between; align-items: baseline; }
.model h3 { margin: 0; font-size: 22px; letter-spacing: -.015em; }
.size { font-family: var(--mono); font-size: 13px; color: var(--tertiary); }
.model-tag { margin: 6px 0 10px; color: var(--accent); font-weight: 650; font-size: 14px; }
.model p { color: var(--secondary); margin: 0 0 16px; font-size: 15px; }
.model code { font-size: 12.5px; background: var(--track); padding: 3px 8px; border-radius: 6px; color: var(--secondary); }
.note { margin-top: 22px; font-size: 14px; color: var(--tertiary); max-width: 720px; }

.reqs { padding-left: 18px; margin: 0 0 6px; color: var(--secondary); font-size: 15.5px; }
.reqs li { margin: 4px 0; }
.tabs { display: flex; gap: 4px; padding: 8px 8px 0 12px; border-bottom: 1px solid var(--line); align-items: center; }
.tabs button { font: inherit; font-size: 13.5px; background: none; border: 0; color: var(--tertiary); padding: 8px 12px; cursor: pointer; border-bottom: 2px solid transparent; margin-bottom: -1px; }
.tabs button[aria-selected="true"] { color: var(--ink); border-bottom-color: var(--accent); font-weight: 600; }
.tabs .copy { margin-left: auto; font-size: 12.5px; border: 1px solid var(--line); border-radius: 7px; padding: 3px 10px; margin-bottom: 6px; }
.tabs .copy:hover { color: var(--ink); }

.chips { list-style: none; padding: 0; margin: 0; display: flex; flex-wrap: wrap; gap: 10px; }
.chips li { background: var(--raised); border: 1px solid var(--line); border-radius: 999px; padding: 8px 16px; font-size: 14.5px; color: var(--secondary); text-decoration: line-through; text-decoration-color: color-mix(in srgb, var(--tertiary) 50%, transparent); }

.final { padding: 110px 0; text-align: center; }
.final-inner { display: flex; flex-direction: column; align-items: center; }
.final p { color: var(--secondary); font-size: 17.5px; margin: 0 0 28px; max-width: 34em; }

.foot { border-top: 1px solid var(--line); padding: 26px 0; font-size: 13.5px; color: var(--secondary); }
.foot-inner { display: flex; flex-wrap: wrap; gap: 14px 28px; align-items: center; justify-content: space-between; }
.foot-links { display: flex; gap: 18px; }
.foot a { text-decoration: none; } .foot a:hover { color: var(--ink); }

/* Reveal on scroll */
.reveal { opacity: 0; transform: translateY(14px); transition: opacity .6s ease, transform .6s ease; }
.reveal.in { opacity: 1; transform: none; }

/* Chinese typography */
html[lang="zh-CN"] h1 { letter-spacing: -.01em; line-height: 1.18; font-size: clamp(34px, 4.2vw, 52px); }
html[lang="zh-CN"] h2 { letter-spacing: 0; }
html[lang="zh-CN"] .kicker { letter-spacing: .08em; }

/* Responsive */
@media (max-width: 1020px) {
  .hero-grid, .split { grid-template-columns: 1fr; gap: 40px; }
  .cards { grid-template-columns: repeat(2, 1fr); }
  .pipeline { grid-template-columns: 1fr; }
  .pipeline li:not(:last-child)::after { top: auto; bottom: -14px; left: 34px; right: auto; width: 2px; height: 14px; }
  .window { transform: none; }
}
@media (max-width: 720px) {
  .links { display: none; }
  .hero { padding: 44px 0 36px; }
  .facts-grid { grid-template-columns: 1fr 1fr; }
  .facts-grid div:nth-child(3) { border-left: 0; }
  .facts-grid div:nth-child(n+3) { border-top: 1px solid var(--line); }
  .cards, .models { grid-template-columns: 1fr; }
  .section { padding: 64px 0; }
  .window { grid-template-columns: 1fr; min-height: 0; }
  .win-side { display: none; }
  .segments li { grid-template-columns: 58px 1fr; }
  .lang-chip { display: none; }
  .nav-actions .btn-small span { display: none; }
}