:root {
  --bg: #0a0c12;
  --bg-soft: #10131c;
  --panel: #141824;
  --panel-2: #191e2b;
  --line: #262c3b;
  --line-soft: #1d2230;
  --ink: #eef1f7;
  --muted: #9aa3b5;
  --faint: #6b7488;
  --gold: #e9b45c;
  --gold-soft: #f3d49b;
  --teal: #5fd3c4;
  --red: #f07070;
  --green: #71d18a;
  --radius: 16px;
  --radius-sm: 10px;
  --mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;
  --sans: ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans SC",
    "PingFang SC", "Microsoft YaHei", sans-serif;
  --shadow: 0 24px 60px rgba(0, 0, 0, .45);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background:
    radial-gradient(1000px 520px at 80% -8%, rgba(233, 180, 92, .10), transparent 60%),
    radial-gradient(800px 500px at 8% 0%, rgba(95, 211, 196, .07), transparent 55%),
    var(--bg);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
a { color: inherit; text-decoration: none; }
a:hover { color: var(--gold-soft); }
img, svg { max-width: 100%; display: block; }
button { font: inherit; cursor: pointer; }
::selection { background: rgba(233, 180, 92, .28); }

.wrap { width: min(1160px, calc(100% - 40px)); margin: 0 auto; }
.narrow { width: min(820px, calc(100% - 40px)); margin: 0 auto; }

/* ── nav ───────────────────────────────────────────────────────────── */
.nav {
  position: sticky; top: 0; z-index: 50;
  backdrop-filter: blur(14px);
  background: rgba(10, 12, 18, .72);
  border-bottom: 1px solid rgba(38, 44, 59, .7);
}
.nav-inner { display: flex; align-items: center; gap: 28px; height: 66px; }
.brand { display: flex; align-items: center; gap: 10px; font-weight: 650; letter-spacing: .2px; }
.brand-mark { width: 26px; height: 26px; flex: none; display: block; filter: drop-shadow(0 2px 8px rgba(233, 180, 92, .18)); }
.brand-name { display: inline-flex; align-items: baseline; gap: 9px; }
.brand-cn {
  font-size: 10.5px; font-weight: 650; letter-spacing: .16em; text-indent: .16em;
  color: var(--gold-soft); line-height: 1.5;
  padding: 1px 7px; border-radius: 999px;
  border: 1px solid rgba(233, 180, 92, .3); background: rgba(233, 180, 92, .08);
  transform: translateY(-1px);
}
.nav-links { display: flex; gap: 22px; margin-left: 8px; color: var(--muted); font-size: 14.5px; }
.nav-links a:hover { color: var(--ink); }
.nav-cta { margin-left: auto; display: flex; align-items: center; gap: 12px; }

/* ── brand reveal: sin² + cos² = 1 → sincosone 合弦 ───────────────── */
.brand-stage[hidden] { display: none; }
.brand-stage {
  position: relative; height: clamp(72px, 7.4vw, 104px);
  margin: 0 0 clamp(18px, 2.2vw, 28px);
  display: flex; align-items: center;
}
.brand-eq {
  position: absolute; left: 0; top: 50%;
  transform: translateY(-50%) scale(1);
  display: inline-flex; align-items: baseline; gap: .6em;
  font-family: "Iowan Old Style", "Palatino Linotype", "Times New Roman", serif;
  font-size: clamp(24px, 2.8vw, 38px); line-height: 1; font-style: italic;
  color: #c9d1e0; white-space: nowrap; opacity: 0;
  animation: eqFade .4s .08s both, eqGap .45s 1.12s both, eqOut .4s 1.6s both;
}
.brand-eq .eq-sup {
  display: inline-block; max-width: 1.2em; overflow: hidden;
  font-size: .58em; font-style: normal; vertical-align: super; line-height: 1;
  animation: supOut .4s 1.12s both;
}
.brand-eq .eq-op {
  display: inline-block; max-width: 1.3em; overflow: hidden;
  color: var(--faint); font-style: normal;
  animation: opOut .4s 1.12s both;
}
.brand-eq .eq-num { color: var(--gold); font-style: normal; }

.brand-word {
  position: absolute; inset: 0;
  display: flex; align-items: center;
  gap: clamp(10px, 1.2vw, 16px);
}
.brand-word .bw-en {
  display: inline-flex; align-items: baseline;
  font-size: clamp(34px, 4.2vw, 56px); font-weight: 680;
  letter-spacing: -1.4px; line-height: 1;
}
.bw-l { display: inline-block; opacity: 1; animation: bwIn .42s both; }
.bw-l:nth-child(1) { animation-delay: 1.60s; }
.bw-l:nth-child(2) { animation-delay: 1.625s; }
.bw-l:nth-child(3) { animation-delay: 1.65s; }
.bw-l:nth-child(4) { animation-delay: 1.675s; }
.bw-l:nth-child(5) { animation-delay: 1.70s; }
.bw-l:nth-child(6) { animation-delay: 1.725s; }
.bw-l:nth-child(7) { animation-delay: 1.75s; }
.bw-l:nth-child(8) { animation-delay: 1.775s; }
.bw-l:nth-child(9) { animation-delay: 1.80s; }
.bw-one { color: var(--gold); }
.bw-cn {
  font-size: clamp(18px, 2.1vw, 26px); font-weight: 600; line-height: 1.15;
  letter-spacing: .2em; text-indent: .2em; color: var(--gold-soft);
  padding-left: clamp(14px, 1.6vw, 24px); border-left: 1px solid var(--line);
  opacity: 1; animation: cnIn .4s 1.95s both;
}
.brand-word::after {
  content: ""; position: absolute; left: 0; bottom: clamp(8px, 1.1vw, 12px); height: 1px; width: 100%;
  background: linear-gradient(90deg, rgba(233, 180, 92, .85), rgba(233, 180, 92, 0));
  transform: scaleX(1); transform-origin: left center;
  animation: sweep .55s 2.0s both;
}

@keyframes eqFade { from { opacity: 0; } to { opacity: 1; } }
@keyframes eqGap { from { gap: .6em; } to { gap: 0em; } }
@keyframes eqOut {
  from { opacity: 1; transform: translateY(-50%) scale(1); }
  to   { opacity: 0; transform: translateY(-50%) scale(.97); }
}
@keyframes supOut {
  from { max-width: 1.2em; opacity: 1; transform: translateY(0); }
  to   { max-width: 0; opacity: 0; transform: translateY(-4px); }
}
@keyframes opOut {
  from { max-width: 1.3em; opacity: 1; }
  to   { max-width: 0; opacity: 0; }
}
@keyframes bwIn {
  from { opacity: 0; transform: translateY(10px); filter: blur(7px); }
  to   { opacity: 1; transform: translateY(0); filter: blur(0); }
}
@keyframes cnIn { from { opacity: 0; transform: translateX(-6px); } to { opacity: 1; transform: none; } }
@keyframes sweep { from { transform: scaleX(0); } to { transform: scaleX(1); } }

/* Static fallback: no replay this session, or reduced motion. */
.brand-stage.is-static .brand-eq { display: none; }
.brand-stage.is-static *,
.brand-stage.is-static *::after { animation: none !important; }

@media (prefers-reduced-motion: reduce) {
  .brand-eq { display: none; }
  .brand-stage *,
  .brand-stage *::after { animation: none !important; }
}

/* ── buttons ───────────────────────────────────────────────────────── */
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 10px 18px; border-radius: 999px;
  border: 1px solid var(--line);
  background: var(--panel); color: var(--ink);
  font-size: 14.5px; font-weight: 560; line-height: 1.2;
  transition: .18s ease;
}
.btn:hover { border-color: #3a4258; background: var(--panel-2); color: var(--ink); transform: translateY(-1px); }
.btn-primary {
  background: linear-gradient(180deg, #f0c579, var(--gold));
  color: #1b1406; border-color: transparent;
  box-shadow: 0 6px 24px rgba(233, 180, 92, .22);
}
.btn-primary:hover { background: linear-gradient(180deg, #f6d391, #e9b45c); color: #1b1406; }
.btn-ghost { background: transparent; }
.btn-sm { padding: 8px 14px; font-size: 13.5px; }

/* ── hero ──────────────────────────────────────────────────────────── */
.hero {
  padding: 110px 0 60px; position: relative; overflow: hidden;
  text-align: center;
}
.hero::before {
  content: ""; position: absolute; left: 50%; top: 10px;
  width: min(920px, 94%); height: 470px; transform: translateX(-50%);
  background: radial-gradient(closest-side, rgba(233, 180, 92, .11), transparent 72%);
  pointer-events: none;
}
.hero .wrap { position: relative; z-index: 1; }
.hero h1 { margin: 0 auto 30px; font-size: clamp(38px, 4.5vw, 57px); }
.hero .lede {
  display: flex; flex-wrap: wrap; justify-content: center; gap: 6px 30px;
  margin: 0 auto; max-width: 860px;
  font-size: clamp(18px, 1.6vw, 22px);
}
.hero-actions { justify-content: center; margin-top: 38px; }
.hero-actions .btn { padding: 12px 22px; font-size: 15.5px; }
.hero .statbar { text-align: left; }
.hero::after {
  content: ""; position: absolute; inset: auto 0 0 0; height: 1px;
  background: linear-gradient(90deg, transparent, var(--line), transparent);
}
.eyebrow {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 6px 12px; border-radius: 999px;
  border: 1px solid rgba(233, 180, 92, .25);
  background: rgba(233, 180, 92, .07);
  color: var(--gold-soft); font-size: 12.5px; letter-spacing: .5px;
}
.eyebrow .dot { width: 6px; height: 6px; border-radius: 50%; background: var(--green); box-shadow: 0 0 10px var(--green); }
h1 {
  margin: 22px 0 18px;
  font-size: clamp(38px, 5.2vw, 66px);
  line-height: 1.08; letter-spacing: -1.6px; font-weight: 680;
}
h1 .grad {
  background: linear-gradient(100deg, var(--gold-soft), var(--gold) 50%, #c88b35);
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.lede { font-size: clamp(16px, 1.55vw, 19px); color: var(--muted); max-width: 760px; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 30px; }
.hero-claim {
  margin: 30px 0 0; color: var(--gold-soft);
  font-size: clamp(18px, 1.6vw, 22px); letter-spacing: .02em;
}

.hero-note { margin-top: 14px; color: var(--faint); font-size: 13px; }
.hero-note code { color: var(--gold-soft); }

.statbar {
  max-width: 900px; margin: clamp(40px, 5vw, 58px) auto 0;
  display: grid; grid-template-columns: repeat(4, 1fr);
  border: 1px solid rgba(233, 180, 92, .2); border-radius: var(--radius);
  background: linear-gradient(180deg, rgba(25, 30, 43, .9), rgba(16, 19, 28, .9));
  box-shadow: 0 16px 50px rgba(0, 0, 0, .28);
  overflow: hidden;
}
.stat { padding: clamp(14px, 1.2vw, 18px) clamp(18px, 1.6vw, 24px); border-right: 1px solid var(--line-soft); }
.stat:last-child { border-right: 0; }
.stat .num { font-size: clamp(22px, 2.1vw, 28px); font-weight: 680; letter-spacing: -.6px; line-height: 1.1; }
.stat .num span { color: var(--gold); }
.stat .lbl { color: var(--faint); font-size: 12px; margin-top: 2px; letter-spacing: .3px; line-height: 1.3; }

/* ── sections ──────────────────────────────────────────────────────── */
section { padding: 74px 0; }
section.tight { padding: 46px 0; }
.section-head { max-width: 740px; margin-bottom: 34px; }
.section-head h2 { font-size: clamp(26px, 3vw, 38px); letter-spacing: -1px; margin: 0 0 10px; font-weight: 650; }
.section-head p { color: var(--muted); margin: 0; }
.kicker { color: var(--gold); font-size: 12.5px; letter-spacing: 1.6px; text-transform: uppercase; margin-bottom: 10px; font-weight: 600; }

.grid { display: grid; gap: 18px; }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.card {
  border: 1px solid var(--line); border-radius: var(--radius);
  background: linear-gradient(180deg, rgba(25, 30, 43, .7), rgba(16, 19, 28, .7));
  padding: 26px;
  transition: .2s ease;
}
.card:hover { border-color: #343c50; transform: translateY(-2px); box-shadow: var(--shadow); }
.card h3 { margin: 14px 0 8px; font-size: 19px; letter-spacing: -.2px; }
.card p { margin: 0; color: var(--muted); font-size: 14.5px; }
.card .more { display: inline-block; margin-top: 18px; color: var(--gold-soft); font-size: 13.5px; }
.doc-path { display: block; }
.doc-path:hover { color: var(--ink); }
.icon {
  width: 38px; height: 38px; border-radius: 11px; display: grid; place-items: center;
  background: rgba(233, 180, 92, .10); border: 1px solid rgba(233, 180, 92, .18);
  color: var(--gold-soft);
}
.icon.teal { background: rgba(95, 211, 196, .09); border-color: rgba(95, 211, 196, .18); color: var(--teal); }

/* ── steps ─────────────────────────────────────────────────────────── */
.steps { counter-reset: step; display: grid; gap: 0; border: 1px solid var(--line); border-radius: var(--radius); overflow: hidden; }
.step { display: grid; grid-template-columns: 64px 1fr; gap: 18px; padding: 22px 26px; border-bottom: 1px solid var(--line-soft); background: rgba(16, 19, 28, .55); }
.step:last-child { border-bottom: 0; }
.step::before {
  counter-increment: step; content: "0" counter(step);
  font-family: var(--mono); color: var(--gold); font-size: 14px; padding-top: 4px;
}
.step h4 { margin: 0 0 4px; font-size: 16px; }
.step p { margin: 0; color: var(--muted); font-size: 14px; }

/* ── code ──────────────────────────────────────────────────────────── */
.code {
  position: relative; border: 1px solid var(--line); border-radius: var(--radius-sm);
  background: #0b0e15; overflow: hidden;
}
.code-head { display: flex; align-items: center; justify-content: space-between; padding: 9px 14px; border-bottom: 1px solid var(--line-soft); color: var(--faint); font-size: 12px; letter-spacing: .4px; }
.code pre { margin: 0; padding: 16px 18px; overflow-x: auto; font-family: var(--mono); font-size: 13px; line-height: 1.7; color: #cdd6e6; }
.code pre .c { color: #64708a; }
.code pre .k { color: var(--gold-soft); }
.code pre .s { color: #9cd3a8; }
.copy { border: 1px solid var(--line); background: transparent; color: var(--muted); border-radius: 7px; padding: 4px 9px; font-size: 11.5px; }
.copy:hover { color: var(--ink); border-color: #3a4258; }
.code-wrap { display: grid; gap: 14px; }
.demo-grid { align-items: stretch; }
.demo-col { display: flex; flex-direction: column; }
.demo-col .code { flex: 1; display: flex; flex-direction: column; }
.demo-col .code pre { flex: 1; }
.demo-col > .mt-2:last-child { margin-top: auto; padding-top: 20px; }
@media (min-width: 901px) {
  .demo-col > p.muted { min-height: 3.3em; }
}


/* ── table ─────────────────────────────────────────────────────────── */
.table-wrap { overflow-x: auto; border: 1px solid var(--line); border-radius: var(--radius-sm); }
table { width: 100%; border-collapse: collapse; font-size: 14px; }
th, td { text-align: left; padding: 12px 16px; border-bottom: 1px solid var(--line-soft); }
th { color: var(--faint); font-weight: 560; font-size: 12px; letter-spacing: .7px; text-transform: uppercase; background: rgba(25, 30, 43, .55); }
tr:last-child td { border-bottom: 0; }
td code, p code, li code { font-family: var(--mono); font-size: .92em; color: var(--gold-soft); background: rgba(233, 180, 92, .08); padding: 2px 6px; border-radius: 5px; }

/* ── pricing ───────────────────────────────────────────────────────── */
.price-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; }
.plan { border: 1px solid var(--line); border-radius: var(--radius); padding: 28px; background: rgba(16, 19, 28, .65); position: relative; }
.plan.featured { border-color: rgba(233, 180, 92, .45); background: linear-gradient(180deg, rgba(233, 180, 92, .08), rgba(16, 19, 28, .8)); }
.plan .tag { position: absolute; top: -11px; left: 24px; background: var(--gold); color: #1b1406; font-size: 11.5px; font-weight: 700; padding: 3px 10px; border-radius: 999px; }
.plan h3 { margin: 0 0 4px; font-size: 17px; }
.plan .price { font-size: 38px; font-weight: 680; letter-spacing: -1.4px; margin: 12px 0 2px; }
.plan .price small { font-size: 13px; color: var(--faint); font-weight: 400; letter-spacing: 0; }
.plan ul { list-style: none; padding: 0; margin: 20px 0 0; display: grid; gap: 10px; color: var(--muted); font-size: 14px; }
.plan li::before { content: "✓"; color: var(--gold); margin-right: 9px; font-weight: 700; }
.plan .btn { width: 100%; justify-content: center; margin-top: 22px; }

/* ── callout / faq ─────────────────────────────────────────────────── */
.callout {
  border: 1px solid rgba(233, 180, 92, .25);
  background: rgba(233, 180, 92, .06);
  border-radius: var(--radius-sm); padding: 18px 20px; color: var(--gold-soft); font-size: 14px;
}
.callout strong { color: #ffe3b0; }
.callout.info { border-color: rgba(95, 211, 196, .25); background: rgba(95, 211, 196, .05); color: #b9ece5; }
.callout.warn { border-color: rgba(240, 112, 112, .28); background: rgba(240, 112, 112, .06); color: #f6b9b9; }
.faq { border-top: 1px solid var(--line); }
.faq details { border-bottom: 1px solid var(--line); padding: 18px 0; }
.faq summary { cursor: pointer; font-weight: 560; list-style: none; display: flex; justify-content: space-between; gap: 20px; }
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: "+"; color: var(--gold); font-size: 20px; line-height: 1; }
.faq details[open] summary::after { content: "−"; }
.faq p { color: var(--muted); margin: 12px 0 0; font-size: 14.5px; }

/* ── doc layout ────────────────────────────────────────────────────── */
.doc { display: grid; grid-template-columns: 220px minmax(0, 1fr); gap: 48px; padding: 54px 0 80px; }
.doc-nav { position: sticky; top: 92px; align-self: start; display: grid; gap: 4px; font-size: 14px; }
.doc-nav a { color: var(--muted); padding: 5px 0; }
.doc-nav a:hover { color: var(--gold-soft); }
.doc-body h1 { font-size: clamp(30px, 3.4vw, 44px); margin: 0 0 10px; letter-spacing: -1.2px; }
.doc-body h2 { font-size: 24px; margin: 46px 0 12px; letter-spacing: -.4px; padding-top: 10px; border-top: 1px solid var(--line-soft); }
.doc-body h3 { font-size: 17px; margin: 26px 0 8px; }
.doc-body p, .doc-body li { color: #c3cad9; }
.doc-body ul { padding-left: 20px; }
.doc-body li { margin: 6px 0; }
.doc-body .code { margin: 16px 0; }

/* ── footer ────────────────────────────────────────────────────────── */
footer { border-top: 1px solid var(--line); padding: 42px 0 56px; color: var(--faint); font-size: 13.5px; }
.foot-grid { display: grid; grid-template-columns: 1.6fr 1fr 1fr 1fr; gap: 30px; }
.foot-grid h4 { color: var(--muted); font-size: 12px; letter-spacing: 1px; text-transform: uppercase; margin: 0 0 12px; }
.foot-grid a { display: block; padding: 4px 0; color: var(--faint); }
.foot-grid a:hover { color: var(--gold-soft); }
.foot-bottom { margin-top: 34px; padding-top: 20px; border-top: 1px solid var(--line-soft); display: flex; justify-content: space-between; gap: 20px; flex-wrap: wrap; font-size: 12.5px; }

/* ── misc ──────────────────────────────────────────────────────────── */
.pill { display: inline-flex; align-items: center; gap: 6px; border: 1px solid var(--line); border-radius: 999px; padding: 3px 10px; font-size: 12px; color: var(--muted); }
.pill.green { border-color: rgba(113, 209, 138, .3); color: var(--green); }
.pill.gold { border-color: rgba(233, 180, 92, .3); color: var(--gold-soft); }
.muted { color: var(--muted); }
.mono { font-family: var(--mono); }
.mt-0 { margin-top: 0; } .mt-1 { margin-top: 10px; } .mt-2 { margin-top: 20px; } .mt-3 { margin-top: 32px; }
.mb-0 { margin-bottom: 0; }

@media (max-width: 900px) {
  .nav-inner { flex-wrap: wrap; height: auto; padding: 10px 0 12px; row-gap: 8px; }
  .nav-links {
    display: flex; order: 3; width: 100%; margin-left: 0;
    gap: 18px; overflow-x: auto; padding-bottom: 2px;
  }
  .nav-links a { white-space: nowrap; }
  .nav-cta { order: 2; }
  .statbar { grid-template-columns: repeat(2, 1fr); }
  .stat:nth-child(2) { border-right: 0; }
  .stat:nth-child(-n+2) { border-bottom: 1px solid var(--line-soft); }
  .grid-3, .grid-2, .price-grid { grid-template-columns: 1fr; }
  .doc { grid-template-columns: 1fr; gap: 20px; }
  .doc-nav { position: static; display: flex; flex-wrap: wrap; gap: 14px; }
  .foot-grid { grid-template-columns: 1fr 1fr; }
  .hero { padding-top: 58px; }
}
@media (max-width: 560px) {
  .hero { text-align: left; }
  .hero h1 { margin-left: 0; margin-right: 0; }
  .hero .lede { display: block; margin: 0; }
  .hero .lede span { display: block; }
  .hero-actions { justify-content: flex-start; }
  .hero h1 .grad { display: block; }
  .statbar { grid-template-columns: 1fr; }
  .stat { border-right: 0; border-bottom: 1px solid var(--line-soft); }
  .stat:last-child { border-bottom: 0; }
  .nav-cta .btn-ghost { display: none; }
  .wrap { width: calc(100% - 28px); }
}


/* ── key request form ─────────────────────────────────────────────── */
.form { display: grid; gap: 14px; max-width: 620px; }
.field { display: grid; gap: 6px; }
.field label { font-size: 13px; color: var(--muted); }
.field input, .field textarea, .field select {
  width: 100%; padding: 11px 14px; border-radius: 10px;
  border: 1px solid var(--line); background: #0c0f17; color: var(--ink);
  font: inherit; font-size: 14px; outline: none;
}
.field input:focus, .field textarea:focus {
  border-color: rgba(233, 180, 92, .55);
  box-shadow: 0 0 0 3px rgba(233, 180, 92, .10);
}
.field textarea { min-height: 110px; resize: vertical; }
.form-note { color: var(--faint); font-size: 12.5px; }
.form-status { font-size: 14px; min-height: 22px; }
.form-status.ok { color: var(--green); }
.form-status.err { color: var(--red); }