:root {
  --canvas: #fafbfd;
  --canvas-muted: #f6f8fb;
  --white: #ffffff;
  --ink: #0f172a;
  --ink-2: #334155;
  --slate: #64748b;
  --slate-4: #94a3b8;
  --line: #e2e8f0;
  --primary: #2563eb;
  --primary-pressed: #1d4ed8;
  --primary-soft: #eff4ff;
  --glow: #dcebff;
  --header-h: 64px;
  --shell: 1080px;
  --doc: 72ch;
  --gutter: clamp(18px, 4vw, 36px);
  --radius: 16px;
  --font: "PingFang SC", "Hiragino Sans GB", "Noto Sans SC", "Inter", system-ui, sans-serif;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.75;
  color: var(--ink-2);
  background: var(--canvas);
  -webkit-font-smoothing: antialiased;
}

::selection {
  background: rgba(37, 99, 235, 0.18);
}

a {
  color: var(--primary);
  text-decoration: none;
}

a:hover {
  color: var(--primary-pressed);
}

.sky {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
  background:
    radial-gradient(820px 420px at 50% -12%, rgba(220, 235, 255, 0.95), transparent 62%),
    linear-gradient(180deg, #f4f8ff 0%, var(--canvas) 38%);
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  height: var(--header-h);
  background: rgba(250, 251, 253, 0.88);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--line);
}

.site-header__inner,
.shell,
.footer-inner {
  position: relative;
  z-index: 1;
  width: min(var(--shell), calc(100% - var(--gutter) * 2));
  margin: 0 auto;
}

.site-header__inner {
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
}

.brand__mark {
  width: 32px;
  height: 32px;
  border-radius: 10px;
  display: grid;
  place-items: center;
  background: var(--ink);
  color: #fff;
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.04em;
}

.brand__name {
  display: block;
  font-weight: 700;
  font-size: 15px;
  letter-spacing: -0.02em;
}

.brand__sub {
  display: block;
  font-size: 12px;
  color: var(--slate);
}

.header-end {
  display: flex;
  align-items: center;
  gap: 18px;
  flex-wrap: wrap;
  justify-content: flex-end;
}

.langs {
  display: flex;
  gap: 8px;
  font-size: 12px;
  font-weight: 600;
}

.langs a {
  color: var(--slate-4);
}

.langs a[aria-current="true"] {
  color: var(--ink);
}

.nav {
  display: flex;
  gap: 18px;
  font-size: 14px;
  font-weight: 600;
}

.nav a {
  color: var(--slate);
}

.nav a[aria-current="page"],
.nav a:hover {
  color: var(--ink);
}

main.shell {
  padding: 36px 0 72px;
}

.page-hero h1 {
  margin: 8px 0 12px;
  font-size: clamp(28px, 4vw, 40px);
  line-height: 1.2;
  letter-spacing: -0.03em;
  color: var(--ink);
}

.hero__eyebrow {
  margin: 0;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--primary);
}

.lede {
  max-width: 68ch;
  margin: 0 0 16px;
  color: var(--ink-2);
}

.meta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 16px;
  font-size: 13px;
  color: var(--slate);
}

.disclaimer {
  margin: 24px 0 28px;
  padding: 14px 16px;
  border: 1px solid #bfdbfe;
  background: var(--primary-soft);
  border-radius: 12px;
  color: var(--ink);
  font-size: 14.5px;
}

.doc-layout {
  display: grid;
  grid-template-columns: 220px minmax(0, 1fr);
  gap: 28px;
  align-items: start;
}

.card {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: 0 10px 30px rgba(15, 23, 42, 0.04);
}

.toc-card {
  position: sticky;
  top: calc(var(--header-h) + 16px);
  padding: 18px 16px;
}

.toc-card h2 {
  margin: 0 0 10px;
  font-size: 13px;
  color: var(--slate);
  font-weight: 600;
}

.toc-card a {
  display: block;
  padding: 6px 8px;
  margin: 0 -8px;
  border-radius: 8px;
  color: var(--ink-2);
  font-size: 13.5px;
  line-height: 1.45;
}

.toc-card a:hover {
  background: var(--primary-soft);
  color: var(--primary);
}

.prose-card {
  padding: clamp(22px, 4vw, 40px);
}

.prose-card h2 {
  margin: 1.8em 0 0.7em;
  font-size: 1.2rem;
  color: var(--ink);
  letter-spacing: -0.02em;
}

.prose-card h2:first-child {
  margin-top: 0;
}

.prose-card p,
.prose-card li {
  max-width: var(--doc);
}

.prose-card p {
  margin: 0 0 0.9em;
}

.prose-card ol {
  margin: 0 0 1em;
  padding-left: 1.2em;
}

.prose-card li + li {
  margin-top: 0.45em;
}

.home-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
  margin-top: 28px;
}

.home-card {
  display: block;
  padding: 22px 22px 20px;
  color: inherit;
}

.home-card h2 {
  margin: 0 0 8px;
  font-size: 20px;
  color: var(--ink);
}

.home-card p {
  margin: 0;
  color: var(--slate);
  font-size: 14.5px;
}

.home-card:hover {
  border-color: #bfdbfe;
}

.site-footer {
  position: relative;
  z-index: 1;
  border-top: 1px solid var(--line);
  padding: 22px 0 32px;
  color: var(--slate);
  font-size: 13px;
}

.footer-inner {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap;
}

@media (max-width: 860px) {
  .doc-layout {
    grid-template-columns: 1fr;
  }

  .toc-card {
    position: static;
  }

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

/* —— 官网首页 —— */
.landing {
  --display: "Syne", "PingFang SC", sans-serif;
  --serif: "Fraunces", "Songti SC", serif;
}

.landing-sky {
  background:
    radial-gradient(900px 520px at 78% -10%, rgba(37, 99, 235, 0.22), transparent 58%),
    radial-gradient(700px 480px at -8% 8%, rgba(6, 182, 212, 0.12), transparent 60%),
    linear-gradient(180deg, #e8f0ff 0%, var(--canvas) 42%);
}

.grain {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 2;
  opacity: 0.18;
  mix-blend-mode: multiply;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='160' height='160'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.85' numOctaves='2' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='.35'/%3E%3C/svg%3E");
}

.landing-header {
  background: rgba(250, 251, 253, 0.72);
}

.hero-stage {
  position: relative;
  z-index: 1;
  min-height: min(100svh, 920px);
  display: grid;
  align-items: center;
  padding: 28px 0 48px;
}

.hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(280px, 0.95fr);
  gap: 40px;
  align-items: center;
}

.hero-copy h1 {
  margin: 10px 0 16px;
  font-family: var(--serif);
  font-size: clamp(36px, 5.4vw, 64px);
  font-weight: 650;
  line-height: 1.08;
  letter-spacing: -0.03em;
  color: var(--ink);
}

.hero-copy h1 em {
  font-style: italic;
  color: var(--primary);
}

.hero-lede {
  font-size: 17px;
  max-width: 42ch;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 22px 0 18px;
}

.btn-ink,
.btn-ghost {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  height: 44px;
  padding: 0 18px;
  border-radius: 999px;
  font-weight: 700;
  font-size: 14px;
}

.btn-ink {
  background: var(--ink);
  color: #fff;
}

.btn-ink:hover {
  background: #1e293b;
  color: #fff;
}

.btn-ghost {
  border: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.7);
  color: var(--ink);
}

.hero-pills {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  padding: 0;
  margin: 0;
  list-style: none;
}

.hero-pills li {
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.04em;
  color: var(--primary);
  background: var(--primary-soft);
  border: 1px solid #dbeafe;
  border-radius: 999px;
  padding: 5px 10px;
}

.radar {
  position: relative;
  aspect-ratio: 1;
  max-width: 460px;
  margin-left: auto;
  border-radius: 28px;
  background:
    radial-gradient(circle at 50% 46%, rgba(255, 255, 255, 0.9), rgba(239, 246, 255, 0.4) 42%, transparent 68%),
    linear-gradient(180deg, #fff, #eef4ff);
  border: 1px solid #dbe7f8;
  box-shadow: 0 30px 60px rgba(37, 99, 235, 0.12);
  overflow: hidden;
}

.radar__rings span {
  position: absolute;
  inset: 18%;
  border: 1px solid rgba(37, 99, 235, 0.16);
  border-radius: 50%;
  animation: pulse 5.4s ease-in-out infinite;
}

.radar__rings span:nth-child(2) {
  inset: 28%;
  animation-delay: 0.6s;
}

.radar__rings span:nth-child(3) {
  inset: 38%;
  animation-delay: 1.2s;
}

.radar__sweep {
  position: absolute;
  inset: 12%;
  border-radius: 50%;
  background: conic-gradient(from 0deg, transparent 0 72%, rgba(37, 99, 235, 0.18) 88%, transparent 100%);
  animation: spin 8s linear infinite;
}

.radar__core {
  position: absolute;
  left: 50%;
  top: 46%;
  transform: translate(-50%, -50%);
  text-align: center;
  z-index: 2;
}

.radar__field {
  min-width: 148px;
  height: 40px;
  display: grid;
  place-items: center;
  border-radius: 999px;
  background: #fff;
  border: 1px solid #e2e8f0;
  font-family: var(--display);
  font-weight: 700;
  color: var(--ink);
  box-shadow: 0 8px 20px rgba(15, 23, 42, 0.06);
}

.radar__core p {
  margin: 10px 0 0;
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--slate);
}

.node {
  position: absolute;
  z-index: 3;
  padding: 5px 9px;
  border-radius: 999px;
  background: #0f172a;
  color: #fff;
  font-size: 11px;
  font-weight: 600;
  animation: floaty 4.8s ease-in-out infinite;
}

.n1 { top: 16%; left: 18%; animation-delay: 0s; }
.n2 { top: 22%; right: 14%; animation-delay: 0.4s; }
.n3 { bottom: 28%; left: 12%; animation-delay: 0.8s; }
.n4 { bottom: 18%; right: 18%; animation-delay: 1.1s; }
.n5 { top: 48%; left: 6%; animation-delay: 0.2s; }
.n6 { top: 52%; right: 8%; animation-delay: 0.9s; }

@keyframes spin {
  to { transform: rotate(360deg); }
}

@keyframes pulse {
  0%, 100% { transform: scale(1); opacity: 0.7; }
  50% { transform: scale(1.04); opacity: 1; }
}

@keyframes floaty {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-7px); }
}

.stats-band {
  position: relative;
  z-index: 1;
  border-block: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.72);
}

.stats-row {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 12px;
  padding: 22px 0;
}

.stats-row div {
  padding-right: 12px;
}

.stats-row strong {
  display: block;
  font-family: var(--display);
  font-size: 15px;
  color: var(--ink);
}

.stats-row span {
  display: block;
  margin-top: 4px;
  font-size: 13px;
  color: var(--slate);
}

.section {
  position: relative;
  z-index: 1;
  padding: 72px 0;
}

.section-alt {
  background: rgba(255, 255, 255, 0.55);
}

.section-title {
  margin: 8px 0 10px;
  font-family: var(--serif);
  font-size: clamp(28px, 3.4vw, 40px);
  letter-spacing: -0.03em;
  color: var(--ink);
}

.section-lede {
  max-width: 52ch;
  margin: 0 0 28px;
  color: var(--slate);
}

.feat-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.feat {
  padding: 22px;
  border-radius: 18px;
  background: #fff;
  border: 1px solid var(--line);
}

.feat__num {
  font-family: var(--display);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--primary);
}

.feat h3 {
  margin: 8px 0 8px;
  font-size: 20px;
  color: var(--ink);
}

.feat p {
  margin: 0;
  color: var(--ink-2);
  font-size: 14.5px;
}

.steps {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
  padding: 0;
  margin: 0;
  list-style: none;
  counter-reset: step;
}

.steps li {
  counter-increment: step;
  padding: 22px;
  border-radius: 18px;
  background: #fff;
  border: 1px solid var(--line);
}

.steps li::before {
  content: counter(step, decimal-leading-zero);
  display: block;
  font-family: var(--display);
  font-weight: 800;
  font-size: 22px;
  color: var(--primary);
  margin-bottom: 10px;
}

.steps strong {
  display: block;
  color: var(--ink);
  font-size: 17px;
  margin-bottom: 6px;
}

.steps span {
  color: var(--ink-2);
  font-size: 14.5px;
}

.bound {
  display: grid;
  grid-template-columns: minmax(0, 0.9fr) minmax(0, 1.1fr);
  gap: 28px;
  align-items: start;
}

.bound-list {
  margin: 0;
  padding: 8px 0 0;
  list-style: none;
}

.bound-list li {
  padding: 14px 0;
  border-top: 1px solid var(--line);
  font-size: 16px;
  color: var(--ink);
}

.contact-box {
  display: flex;
  justify-content: space-between;
  gap: 20px;
  align-items: end;
  flex-wrap: wrap;
}

.mail-chip {
  font-family: var(--display);
  font-size: clamp(22px, 3vw, 32px);
  font-weight: 700;
  color: var(--ink);
  border-bottom: 2px solid var(--primary);
  padding-bottom: 4px;
}

.mail-chip:hover {
  color: var(--primary);
}

@media (max-width: 900px) {
  .hero-grid,
  .bound,
  .feat-grid,
  .steps,
  .stats-row {
    grid-template-columns: 1fr;
  }

  .radar {
    margin: 0 auto;
    max-width: 360px;
  }

  .nav {
    gap: 10px;
    font-size: 12px;
  }

  .hero-stage {
    min-height: auto;
    padding-top: 18px;
  }
}