/* arcthis site — terminal-adaptive design system
   Light and dark are separately derived themes over shared semantic tokens. */

:root {
  color-scheme: light;

  --bg-base: #fafafa;
  --bg-surface: #ffffff;
  --bg-elevated: #f3f4f6;
  --bg-subtle: #f7f7f9;
  --bg-inset: #f0f1f4;

  --border-subtle: #dedfe3;
  --border-strong: #c7cad1;

  --text-primary: #17181b;
  --text-secondary: #5d6169;
  --text-tertiary: #767b84;
  --text-disabled: #a4a8b0;

  --accent: #0878d1;
  --accent-hover: #0668b6;
  --accent-soft: #e9f4ff;
  --focus-ring: #0878d1;

  --syntax-keyword: #7c3aed;
  --syntax-string: #137547;
  --syntax-function: #0868b8;
  --syntax-number: #a94721;
  --syntax-comment: #68707c;
  --syntax-constant: #805900;
  --syntax-error: #bd3039;

  --ok: #137547;
  --warn: #805900;

  --button-primary-bg: #0878d1;
  --button-primary-fg: #ffffff;
  --button-primary-hover: #0668b6;

  --dot-red: #ff5f57;
  --dot-yellow: #febc2e;
  --dot-green: #28c840;

  --selection: rgba(8, 120, 209, 0.18);

  --sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans CJK SC", sans-serif;
  --mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;

  --maxw: 1160px;
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
}

[data-theme="dark"] {
  color-scheme: dark;

  --bg-base: #090b0d;
  --bg-surface: #101216;
  --bg-elevated: #16181d;
  --bg-subtle: #0d0f12;
  --bg-inset: #0b0d10;

  --border-subtle: #242830;
  --border-strong: #333842;

  --text-primary: #e7e9ed;
  --text-secondary: #9ba1ac;
  --text-tertiary: #7d8590;
  --text-disabled: #505761;

  --accent: #82aaff;
  --accent-hover: #a8c2ff;
  --accent-soft: #172238;
  --focus-ring: #82aaff;

  --syntax-keyword: #c792ea;
  --syntax-string: #c3e88d;
  --syntax-function: #82aaff;
  --syntax-number: #f78c6c;
  --syntax-comment: #7d8590;
  --syntax-constant: #ffcb6b;
  --syntax-error: #f07178;

  --ok: #7fce9f;
  --warn: #ffcb6b;

  --button-primary-bg: #e7e9ed;
  --button-primary-fg: #090b0d;
  --button-primary-hover: #ffffff;

  --selection: rgba(130, 170, 255, 0.22);
}

/* ---------- base ---------- */

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

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

html.lenis, html.lenis body { height: auto; }
.lenis.lenis-smooth { scroll-behavior: auto !important; }

body {
  margin: 0;
  background: var(--bg-base);
  color: var(--text-primary);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

::selection { background: var(--selection); }

h1, h2, h3, h4 { margin: 0; font-weight: 600; letter-spacing: -0.02em; }
p { margin: 0; }
a { color: var(--accent); text-decoration: none; }
a:hover { color: var(--accent-hover); }
ul, ol { margin: 0; padding: 0; list-style: none; }
button { font: inherit; color: inherit; background: none; border: 0; cursor: pointer; padding: 0; }
img, svg { display: block; }

code, pre, kbd, .mono { font-family: var(--mono); }

:focus-visible {
  outline: 2px solid var(--focus-ring);
  outline-offset: 2px;
  border-radius: 4px;
}

.wrap {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 24px;
}

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  background: var(--bg-surface);
  color: var(--text-primary);
  padding: 8px 16px;
  z-index: 200;
  border: 1px solid var(--border-subtle);
}
.skip-link:focus { left: 8px; top: 8px; }

/* ---------- nav ---------- */

.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: color-mix(in srgb, var(--bg-base) 82%, transparent);
  backdrop-filter: saturate(1.4) blur(12px);
  -webkit-backdrop-filter: saturate(1.4) blur(12px);
  border-bottom: 1px solid var(--border-subtle);
}

.nav-inner {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 24px;
  height: 60px;
  display: flex;
  align-items: center;
  gap: 28px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--text-primary);
  font-weight: 600;
  font-size: 16px;
  letter-spacing: -0.01em;
}
.brand:hover { color: var(--text-primary); }
.brand svg { width: 26px; height: 26px; }

.nav-links {
  display: flex;
  align-items: center;
  gap: 24px;
  margin-left: 8px;
}
.nav-links a {
  color: var(--text-secondary);
  font-size: 14px;
  font-weight: 450;
}
.nav-links a:hover { color: var(--text-primary); }
.nav-links a[aria-current="page"] { color: var(--text-primary); font-weight: 500; }

.nav-right {
  margin-left: auto;
  display: flex;
  align-items: center;
  gap: 12px;
}

.icon-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 34px;
  height: 34px;
  border-radius: 8px;
  color: var(--text-secondary);
  border: 1px solid transparent;
}
.icon-btn:hover { color: var(--text-primary); background: var(--bg-elevated); }
.icon-btn svg { width: 17px; height: 17px; }

.lang-switch {
  display: inline-flex;
  align-items: center;
  height: 30px;
  padding: 0 11px;
  font-size: 13px;
  font-weight: 500;
  color: var(--text-secondary);
  border: 1px solid var(--border-subtle);
  border-radius: 8px;
  white-space: nowrap;
}
.lang-switch:hover { color: var(--text-primary); border-color: var(--border-strong); }

/* ---------- buttons ---------- */

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  height: 40px;
  padding: 0 18px;
  border-radius: 10px;
  font-size: 14px;
  font-weight: 500;
  letter-spacing: -0.01em;
  white-space: nowrap;
  transition: background 120ms linear, border-color 120ms linear, color 120ms linear;
}
.btn svg { width: 15px; height: 15px; }

.btn-primary {
  background: var(--button-primary-bg);
  color: var(--button-primary-fg);
}
.btn-primary:hover { background: var(--button-primary-hover); color: var(--button-primary-fg); }

.btn-secondary {
  color: var(--text-primary);
  border: 1px solid var(--border-subtle);
  background: var(--bg-surface);
}
.btn-secondary:hover { border-color: var(--border-strong); color: var(--text-primary); }

.btn-sm { height: 34px; padding: 0 14px; border-radius: 8px; font-size: 13px; }

.link-arrow {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 14px;
  font-weight: 500;
}
.link-arrow svg { width: 14px; height: 14px; transition: transform 150ms var(--ease-out); }
.link-arrow:hover svg { transform: translateX(3px); }

/* ---------- hero ---------- */

.hero {
  padding: 96px 0 72px;
}

.hero-grid {
  display: grid;
  grid-template-columns: 5fr 6fr;
  gap: 56px;
  align-items: center;
}

.hero-grid > *,
.quickstart-grid > *,
.split > *,
.stack-card > *,
.section-head > *,
.dl-grid > * {
  min-width: 0;
}

.eyebrow {
  font-family: var(--mono);
  font-size: 12.5px;
  color: var(--text-tertiary);
  letter-spacing: 0.02em;
  margin-bottom: 22px;
  display: flex;
  align-items: center;
  gap: 10px;
}
.eyebrow .sep { color: var(--text-disabled); }

.hero-title {
  font-size: clamp(40px, 4.6vw, 60px);
  line-height: 1.05;
  letter-spacing: -0.035em;
  margin-bottom: 22px;
}

.hero-title .tone-2,
.section-title .tone-2,
.page-title .tone-2,
.cta-title .tone-2 {
  display: block;
  margin-top: 0.22em;
  font-size: 0.62em;
  font-weight: 550;
}

.hero-title, .section-title, .page-title, .cta-title {
  text-wrap: balance;
}
.hero-title .tone-2 { color: var(--text-tertiary); }

.hero-sub {
  font-size: 17px;
  line-height: 1.6;
  color: var(--text-secondary);
  max-width: 46ch;
  margin-bottom: 32px;
}

.hero-actions {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 26px;
}

.hero-meta {
  font-family: var(--mono);
  font-size: 12.5px;
  color: var(--text-tertiary);
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}
.hero-meta .sep { color: var(--text-disabled); }

/* ---------- terminal window ---------- */

.frame {
  padding: 5px;
  border: 1px solid var(--border-subtle);
  border-radius: 17px;
  background: var(--bg-subtle);
}

.term {
  overflow: hidden;
  border: 1px solid var(--border-subtle);
  border-radius: 12px;
  background: var(--bg-surface);
}

.term-bar {
  display: flex;
  align-items: center;
  gap: 8px;
  height: 40px;
  padding: 0 14px;
  border-bottom: 1px solid var(--border-subtle);
  background: var(--bg-elevated);
}

.term-dots { display: flex; gap: 7px; }
.term-dots i {
  width: 11px; height: 11px; border-radius: 50%;
  display: block;
}
.term-dots i:nth-child(1) { background: var(--dot-red); }
.term-dots i:nth-child(2) { background: var(--dot-yellow); }
.term-dots i:nth-child(3) { background: var(--dot-green); }

.term-title {
  margin-left: 8px;
  font-family: var(--mono);
  font-size: 12px;
  color: var(--text-tertiary);
  user-select: none;
}

.term-copy {
  margin-left: auto;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-family: var(--mono);
  font-size: 11.5px;
  color: var(--text-tertiary);
  padding: 4px 8px;
  border-radius: 6px;
  border: 1px solid transparent;
}
.term-copy:hover { color: var(--text-primary); background: var(--bg-inset); border-color: var(--border-subtle); }
.term-copy svg { width: 13px; height: 13px; }
.term-copy.copied { color: var(--ok); }

.term-body {
  padding: 20px 22px;
  font-family: var(--mono);
  font-size: 13px;
  line-height: 1.75;
  overflow-x: auto;
  white-space: pre;
  tab-size: 4;
}

.term-body .tp { color: var(--text-tertiary); user-select: none; }
.term-body .tc { color: var(--text-primary); font-weight: 500; }
.term-body .ta { color: var(--syntax-function); }
.term-body .tf { color: var(--syntax-constant); }
.term-body .ts { color: var(--syntax-string); }
.term-body .to { color: var(--text-secondary); }
.term-body .td { color: var(--text-tertiary); }
.term-body .tok { color: var(--ok); }
.term-body .tw { color: var(--warn); }
.term-body .tn { color: var(--syntax-number); }

/* ---------- code frame (non-terminal) ---------- */

.code-frame {
  overflow: hidden;
  border: 1px solid var(--border-subtle);
  border-radius: 12px;
  background: var(--bg-surface);
}

.code-head {
  display: flex;
  align-items: center;
  gap: 10px;
  height: 40px;
  padding: 0 14px;
  border-bottom: 1px solid var(--border-subtle);
  background: var(--bg-elevated);
  font-family: var(--mono);
  font-size: 12px;
  color: var(--text-tertiary);
}

.code-frame pre {
  margin: 0;
  padding: 18px 20px;
  font-family: var(--mono);
  font-size: 13px;
  line-height: 1.7;
  overflow-x: auto;
  tab-size: 4;
}

.code-frame pre .k { color: var(--syntax-keyword); }
.code-frame pre .s { color: var(--syntax-string); }
.code-frame pre .f { color: var(--syntax-function); }
.code-frame pre .n { color: var(--syntax-number); }
.code-frame pre .c { color: var(--syntax-comment); }
.code-frame pre .p { color: var(--text-secondary); }

/* ---------- sections ---------- */

.section { padding: 84px 0; }

.section-head {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 40px;
  align-items: end;
  margin-bottom: 48px;
}

.section-index {
  font-family: var(--mono);
  font-size: 12.5px;
  color: var(--text-tertiary);
  margin-bottom: 14px;
  display: block;
}

.section-title {
  font-size: clamp(28px, 3vw, 38px);
  line-height: 1.12;
  letter-spacing: -0.03em;
}
.section-title .tone-2 { color: var(--text-tertiary); }

.section-note {
  color: var(--text-secondary);
  font-size: 15.5px;
  line-height: 1.65;
  max-width: 48ch;
  justify-self: end;
}

/* ---------- quickstart ---------- */

.quickstart-grid {
  display: grid;
  grid-template-columns: 5fr 7fr;
  gap: 56px;
  align-items: center;
}

.quickstart-note {
  margin-top: 18px;
  font-size: 13.5px;
  color: var(--text-tertiary);
  max-width: 42ch;
}
.quickstart-note code {
  font-size: 12px;
  background: var(--bg-elevated);
  border: 1px solid var(--border-subtle);
  border-radius: 5px;
  padding: 1px 6px;
}

/* ---------- scroll stack ---------- */

.stack-section { padding: 84px 0 40px; position: relative; z-index: 1; }

.stack-inner {
  padding-top: 4vh;
}

@media (min-width: 1024px) {
  /* trailing room so the section below never slides under the pinned cards */
  .stack-inner { padding-bottom: 50vh; }
}

.stack-card {
  position: relative;
  width: 100%;
  margin: 0 0 100px;
  padding: 44px 48px;
  border-radius: 24px;
  border: 1px solid var(--border-subtle);
  background: var(--bg-surface);
  box-shadow: 0 1px 2px rgba(16, 18, 22, 0.04), 0 12px 40px -12px rgba(16, 18, 22, 0.10);
  transform-origin: top center;
  backface-visibility: hidden;
  will-change: transform;
  display: grid;
  grid-template-columns: 5fr 7fr;
  gap: 48px;
  align-items: center;
}

[data-theme="dark"] .stack-card {
  box-shadow: none;
  background: var(--bg-elevated);
}

.stack-card:last-of-type { margin-bottom: 0; }

.stack-num {
  font-family: var(--mono);
  font-size: 12px;
  color: var(--text-tertiary);
  display: block;
  margin-bottom: 16px;
}

.stack-card h3 {
  font-size: 24px;
  line-height: 1.2;
  letter-spacing: -0.02em;
  margin-bottom: 14px;
}

.stack-card .stack-desc {
  color: var(--text-secondary);
  font-size: 15px;
  line-height: 1.65;
  max-width: 38ch;
}

.stack-card .stack-desc code {
  font-family: var(--mono);
  font-size: 12.5px;
  background: var(--bg-elevated);
  border: 1px solid var(--border-subtle);
  border-radius: 5px;
  padding: 1px 6px;
  white-space: nowrap;
}

[data-theme="dark"] .stack-card .stack-desc code { background: var(--bg-inset); }

.stack-card .term-body { font-size: 12.5px; padding: 18px 20px; }

.stack-end { width: 100%; height: 1px; }

/* ---------- tables ---------- */

.table-frame {
  border: 1px solid var(--border-subtle);
  border-radius: 12px;
  overflow: hidden;
  background: var(--bg-surface);
}

.table-scroll { overflow-x: auto; }

table.data {
  width: 100%;
  border-collapse: collapse;
  font-size: 13.5px;
}

table.data th {
  text-align: left;
  font-weight: 500;
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-tertiary);
  padding: 12px 18px;
  border-bottom: 1px solid var(--border-subtle);
  background: var(--bg-elevated);
  white-space: nowrap;
}

table.data td {
  padding: 11px 18px;
  border-bottom: 1px solid var(--border-subtle);
  color: var(--text-secondary);
  vertical-align: top;
}

table.data tr:last-child td { border-bottom: 0; }
table.data td:first-child { color: var(--text-primary); font-family: var(--mono); font-size: 12.5px; white-space: nowrap; }
table.data td .mono { font-size: 12.5px; color: var(--text-primary); }
table.data td.num { text-align: right; font-family: var(--mono); font-size: 12.5px; }

.pill {
  display: inline-block;
  font-family: var(--mono);
  font-size: 11px;
  padding: 1px 8px;
  border-radius: 999px;
  border: 1px solid var(--border-subtle);
  color: var(--text-tertiary);
  white-space: nowrap;
}
.pill.yes { color: var(--ok); border-color: color-mix(in srgb, var(--ok) 35%, transparent); }
.pill.no { color: var(--text-disabled); }
.pill.planned { color: var(--warn); border-color: color-mix(in srgb, var(--warn) 35%, transparent); }

/* ---------- definition columns ---------- */

.def-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0;
  border: 1px solid var(--border-subtle);
  border-radius: 12px;
  background: var(--bg-surface);
  overflow: hidden;
}

.def-item {
  padding: 26px 26px 30px;
  border-left: 1px solid var(--border-subtle);
}
.def-item:first-child { border-left: 0; }

.def-item .def-k {
  font-family: var(--mono);
  font-size: 11.5px;
  color: var(--text-tertiary);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  display: block;
  margin-bottom: 12px;
}

.def-item h3 { font-size: 16.5px; font-weight: 550; margin-bottom: 10px; letter-spacing: -0.01em; }
.def-item p { font-size: 13.5px; color: var(--text-secondary); line-height: 1.6; }

/* ---------- error chips ---------- */

.chip-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.chip {
  font-family: var(--mono);
  font-size: 12px;
  color: var(--text-secondary);
  border: 1px solid var(--border-subtle);
  background: var(--bg-surface);
  border-radius: 7px;
  padding: 4px 10px;
  white-space: nowrap;
}

/* ---------- split block (mcp / agent) ---------- */

.split {
  display: grid;
  grid-template-columns: 5fr 7fr;
  gap: 56px;
  align-items: center;
}

.split-reverse { grid-template-columns: 7fr 5fr; }

.fact-list { margin-top: 22px; }
.fact-list li {
  position: relative;
  padding: 10px 0 10px 22px;
  font-size: 14.5px;
  color: var(--text-secondary);
  border-bottom: 1px solid var(--border-subtle);
}
.fact-list li:last-child { border-bottom: 0; }
.fact-list li::before {
  content: "";
  position: absolute;
  left: 2px;
  top: 19px;
  width: 6px;
  height: 6px;
  border-radius: 2px;
  background: var(--accent);
}
.fact-list li strong { color: var(--text-primary); font-weight: 550; }
.fact-list li code {
  font-family: var(--mono);
  font-size: 12.5px;
  background: var(--bg-elevated);
  border: 1px solid var(--border-subtle);
  border-radius: 5px;
  padding: 1px 6px;
  white-space: nowrap;
}

/* ---------- CTA ---------- */

.cta { padding: 96px 0 110px; text-align: center; }

.cta-title {
  font-size: clamp(30px, 3.4vw, 44px);
  letter-spacing: -0.03em;
  line-height: 1.1;
  margin-bottom: 16px;
}
.cta-title .tone-2 { color: var(--text-tertiary); }

.cta-sub { color: var(--text-secondary); font-size: 16px; margin-bottom: 34px; }

.install-chip {
  display: inline-flex;
  align-items: center;
  gap: 14px;
  font-family: var(--mono);
  font-size: 13.5px;
  color: var(--text-primary);
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: 10px;
  padding: 10px 10px 10px 16px;
  margin-bottom: 30px;
}
.install-chip .tp { color: var(--text-tertiary); user-select: none; }
.install-chip button {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-family: var(--mono);
  font-size: 12px;
  color: var(--text-tertiary);
  border: 1px solid var(--border-subtle);
  border-radius: 7px;
  padding: 5px 10px;
  background: var(--bg-elevated);
}
.install-chip button:hover { color: var(--text-primary); }
.install-chip button.copied { color: var(--ok); }
.install-chip svg { width: 13px; height: 13px; }

.cta-actions { display: flex; justify-content: center; gap: 14px; }

/* ---------- footer ---------- */

.footer {
  border-top: 1px solid var(--border-subtle);
  padding: 56px 0 40px;
  background: var(--bg-subtle);
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 48px;
}

.footer-brand p {
  margin-top: 14px;
  font-size: 13.5px;
  color: var(--text-tertiary);
  max-width: 30ch;
  line-height: 1.6;
}

.footer-col h4 {
  font-size: 12px;
  font-weight: 550;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-tertiary);
  margin-bottom: 14px;
}

.footer-col li { margin-bottom: 9px; }
.footer-col a { font-size: 13.5px; color: var(--text-secondary); }
.footer-col a:hover { color: var(--text-primary); }

.footer-bottom {
  display: flex;
  align-items: center;
  gap: 12px;
  padding-top: 24px;
  border-top: 1px solid var(--border-subtle);
  font-family: var(--mono);
  font-size: 12px;
  color: var(--text-tertiary);
  flex-wrap: wrap;
}
.footer-bottom .sep { color: var(--text-disabled); }
.footer-bottom .push { margin-left: auto; }

/* ---------- docs page ---------- */

.page-head { padding: 72px 0 40px; }

.page-title {
  font-size: clamp(34px, 4vw, 48px);
  letter-spacing: -0.03em;
  line-height: 1.08;
  margin-bottom: 16px;
}
.page-title .tone-2 { color: var(--text-tertiary); }

.page-sub { color: var(--text-secondary); font-size: 16.5px; max-width: 62ch; line-height: 1.65; }

.docs-layout {
  display: grid;
  grid-template-columns: 220px 1fr;
  gap: 56px;
  padding-bottom: 96px;
}

.docs-side {
  position: sticky;
  top: 84px;
  align-self: start;
  font-size: 13.5px;
}
.docs-side .side-group { margin-bottom: 22px; }
.docs-side h5 {
  font-size: 11px;
  font-weight: 550;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-tertiary);
  margin: 0 0 8px;
}
.docs-side a {
  display: block;
  padding: 4px 0;
  color: var(--text-secondary);
}
.docs-side a:hover { color: var(--text-primary); }
.docs-side a.mono { font-size: 12.5px; }

.docs-content { min-width: 0; }

.doc-block { margin-bottom: 72px; scroll-margin-top: 84px; }

.doc-block > h2 {
  font-size: 26px;
  letter-spacing: -0.02em;
  margin-bottom: 8px;
}
.doc-block > h2 .anchor { color: var(--text-disabled); font-weight: 400; margin-left: 8px; opacity: 0; transition: opacity 120ms; }
.doc-block > h2:hover .anchor { opacity: 1; }

.doc-block > p.lead { color: var(--text-secondary); font-size: 15px; margin-bottom: 24px; max-width: 68ch; }
.doc-block h3 { font-size: 17px; font-weight: 550; margin: 32px 0 12px; }
.doc-block p { color: var(--text-secondary); font-size: 14.5px; line-height: 1.7; margin-bottom: 12px; max-width: 72ch; }
.doc-block p code, .doc-block li code {
  font-family: var(--mono);
  font-size: 12.5px;
  background: var(--bg-elevated);
  border: 1px solid var(--border-subtle);
  border-radius: 5px;
  padding: 1px 6px;
  white-space: nowrap;
}

.cmd {
  border: 1px solid var(--border-subtle);
  border-radius: 12px;
  background: var(--bg-surface);
  margin-bottom: 14px;
  overflow: hidden;
  scroll-margin-top: 84px;
}

.cmd-head {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding: 14px 20px;
  border-bottom: 1px solid var(--border-subtle);
  background: var(--bg-elevated);
  flex-wrap: wrap;
}

.cmd-name {
  font-family: var(--mono);
  font-size: 14px;
  font-weight: 500;
  color: var(--text-primary);
}

.cmd-sig {
  font-family: var(--mono);
  font-size: 12px;
  color: var(--text-tertiary);
}

.cmd-body { padding: 14px 20px 16px; }
.cmd-body p { font-size: 14px; color: var(--text-secondary); margin: 0 0 10px; }
.cmd-body p:last-child { margin-bottom: 0; }
.cmd-body .flags { font-family: var(--mono); font-size: 12px; color: var(--text-tertiary); }
.cmd-body .flags b { color: var(--text-secondary); font-weight: 500; }

/* ---------- download page ---------- */

.dl-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
  margin-bottom: 64px;
}

.dl-card {
  border: 1px solid var(--border-subtle);
  border-radius: 14px;
  background: var(--bg-surface);
  padding: 26px 28px 28px;
}

.dl-card h3 {
  font-size: 17px;
  font-weight: 550;
  margin-bottom: 6px;
  display: flex;
  align-items: center;
  gap: 10px;
}
.dl-card h3 svg { width: 18px; height: 18px; color: var(--text-secondary); }
.dl-card .dl-desc { font-size: 13.5px; color: var(--text-tertiary); margin-bottom: 16px; }

.dl-card .code-frame pre { font-size: 12.5px; padding: 14px 16px; }

.step-list { counter-reset: step; margin-bottom: 48px; }
.step {
  display: grid;
  grid-template-columns: 44px 1fr;
  gap: 20px;
  padding: 26px 0;
  border-bottom: 1px solid var(--border-subtle);
}
.step:last-child { border-bottom: 0; }

.step-num {
  counter-increment: step;
  width: 34px;
  height: 34px;
  border-radius: 50%;
  border: 1px solid var(--border-strong);
  color: var(--text-secondary);
  font-family: var(--mono);
  font-size: 13px;
  display: flex;
  align-items: center;
  justify-content: center;
}
.step-num::before { content: counter(step); }

.step h3 { font-size: 16.5px; font-weight: 550; margin-bottom: 6px; }
.step p { font-size: 14px; color: var(--text-secondary); margin-bottom: 14px; max-width: 68ch; }
.step p code {
  font-family: var(--mono);
  font-size: 12.5px;
  background: var(--bg-elevated);
  border: 1px solid var(--border-subtle);
  border-radius: 5px;
  padding: 1px 6px;
}

.notice {
  border: 1px solid var(--border-subtle);
  border-left: 3px solid var(--accent);
  border-radius: 0 10px 10px 0;
  background: var(--bg-surface);
  padding: 16px 20px;
  font-size: 14px;
  color: var(--text-secondary);
  margin-bottom: 40px;
}
.notice strong { color: var(--text-primary); font-weight: 550; }
.notice code {
  font-family: var(--mono);
  font-size: 12.5px;
  background: var(--bg-elevated);
  border: 1px solid var(--border-subtle);
  border-radius: 5px;
  padding: 1px 6px;
}

/* ---------- reveal defaults (JS enhances) ---------- */

.reveal { opacity: 1; }

/* ---------- zh-CN typography ---------- */

[lang="zh-CN"] h1, [lang="zh-CN"] h2, [lang="zh-CN"] h3, [lang="zh-CN"] h4,
[lang="zh-CN"] .hero-title, [lang="zh-CN"] .section-title,
[lang="zh-CN"] .page-title, [lang="zh-CN"] .cta-title {
  letter-spacing: 0;
}

/* ---------- responsive ---------- */

@media (max-width: 1024px) {
  .hero-grid { grid-template-columns: 1fr; gap: 44px; }
  .hero { padding: 72px 0 56px; }
  .hero-sub { max-width: 60ch; }
  .quickstart-grid, .split, .split-reverse { grid-template-columns: 1fr; gap: 36px; }
  .section-head { grid-template-columns: 1fr; gap: 16px; align-items: start; }
  .section-note { justify-self: start; }
  .def-grid { grid-template-columns: 1fr 1fr; }
  .def-item:nth-child(3) { border-left: 0; }
  .def-item:nth-child(n+3) { border-top: 1px solid var(--border-subtle); }
  .stack-card { grid-template-columns: 1fr; gap: 28px; padding: 32px 28px; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .docs-layout { grid-template-columns: 1fr; }
  .docs-side { position: static; display: none; }
  .dl-grid { grid-template-columns: 1fr; }
}

@media (max-width: 640px) {
  .wrap { padding: 0 18px; }
  .nav-links { display: none; }
  .hero { padding: 56px 0 48px; }
  .section { padding: 60px 0; }
  .def-grid { grid-template-columns: 1fr; }
  .def-item { border-left: 0; border-top: 1px solid var(--border-subtle); }
  .def-item:first-child { border-top: 0; }
  .stack-card { padding: 24px 20px; border-radius: 18px; }
  .footer-grid { grid-template-columns: 1fr; gap: 28px; }
  .cta-actions { flex-direction: column; align-items: center; }
  .step { grid-template-columns: 34px 1fr; gap: 14px; }
}

/* ---------- reduced motion ---------- */

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}