/* Skein website — single design system shared by every page.
   Authored by Claude Fable 5. Zero external dependencies.
   Design language: neutral near-black, one luminous mint accent used sparingly,
   micro mono-caps labels, tight display type, hairline borders, faint grid + grain. */

:root {
  --bg: #060708;
  --bg-elev: #0b0c0e;
  --bg-raise: #14161a;
  --surface: #0b0d0f;
  --line: rgba(255, 255, 255, 0.07);
  --line-strong: rgba(255, 255, 255, 0.16);
  --text: #f5f7f8;
  --text-soft: #a3a9b0;
  --text-faint: #686e75;
  --accent: #3ee6c5;
  --accent-strong: #17bd97;
  --accent-ink: #03120d;
  --accent-dim: rgba(62, 230, 197, 0.1);
  --warn: #e7c078;
  --danger: #f08c84;
  --term-bg: #0a0c0d;
  --term-text: #e9edf1;
  --term-dim: #798088;
  --term-accent: #45e8c8;
  --term-ok: #63d992;
  --grid-line: rgba(255, 255, 255, 0.04);
  --radius: 16px;
  --radius-sm: 10px;
  --shadow: 0 30px 90px rgba(0, 0, 0, 0.55);
  --font-sans: ui-sans-serif, -apple-system, "Segoe UI", Roboto, "PingFang SC", "Noto Sans", sans-serif;
  --font-mono: ui-monospace, "SF Mono", SFMono-Regular, Menlo, Consolas, monospace;
}

html[data-theme="light"] {
  --bg: #fbfbfa;
  --bg-elev: #ffffff;
  --bg-raise: #eef0ef;
  --surface: #ffffff;
  --line: rgba(10, 14, 13, 0.09);
  --line-strong: rgba(10, 14, 13, 0.2);
  --text: #101413;
  --text-soft: #4e565b;
  --text-faint: #7d8489;
  --accent: #0a8d70;
  --accent-strong: #0a8d70;
  --accent-ink: #f2fffb;
  --accent-dim: rgba(10, 141, 112, 0.09);
  --grid-line: rgba(10, 14, 13, 0.05);
  --shadow: 0 26px 70px rgba(15, 22, 20, 0.14);
}

* { box-sizing: border-box; margin: 0; }

html { scroll-behavior: smooth; }

body {
  font: 16px/1.68 var(--font-sans);
  background: var(--bg);
  color: var(--text);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

code, pre, kbd { font-family: var(--font-mono); }
img { max-width: 100%; height: auto; }
a { color: inherit; }
::selection { background: var(--accent-dim); }

.wrap { max-width: 1120px; margin-inline: auto; padding-inline: 24px; }

.skip-link {
  position: absolute; left: -9999px; top: 0; z-index: 99;
  background: var(--accent); color: var(--accent-ink);
  padding: 10px 16px; border-radius: 999px; font-weight: 650; text-decoration: none;
}
.skip-link:focus { left: 16px; top: 14px; }

/* ---------- bilingual content ----------
   Every visible string exists twice, tagged lang="en" / lang="zh-CN".
   The html[lang] attribute — set before first paint — decides which one shows,
   so no JavaScript is required to read the page in the default language. */

html[lang="zh-CN"] [lang="en"] { display: none; }
html:not([lang="zh-CN"]) [lang="zh-CN"] { display: none; }
html[lang="zh-CN"] body { line-height: 1.78; }
html[lang="zh-CN"] h1,
html[lang="zh-CN"] h2 { letter-spacing: 0.01em; }
html[lang="zh-CN"] .accent { font-style: normal; }

.lang-toggle { font: 650 12.5px/1 var(--font-sans); width: auto; padding-inline: 12px; }
.lang-toggle .lang-zh { display: none; }
html[lang="zh-CN"] .lang-toggle .lang-en { display: none; }
html[lang="zh-CN"] .lang-toggle .lang-zh { display: inline; }

/* ---------- header ---------- */

.site-header {
  position: sticky; top: 0; z-index: 40;
  border-bottom: 1px solid transparent;
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  transition: border-color 200ms ease;
}
.site-header.is-scrolled { border-bottom-color: var(--line); }

.header-inner { display: flex; align-items: center; gap: 20px; height: 64px; }

.brand { display: flex; align-items: center; gap: 10px; text-decoration: none; font-weight: 700; letter-spacing: 0.01em; }
.brand img { width: 33px; height: 23px; }
.brand-mark-light { display: none; }
html[data-theme="light"] .brand-mark-dark { display: none; }
html[data-theme="light"] .brand-mark-light { display: inline; }
.brand-channel {
  font: 620 10px/1 var(--font-mono); color: var(--text-faint);
  border: 1px solid var(--line-strong); border-radius: 5px;
  padding: 4px 6px; letter-spacing: 0.14em;
}

.site-nav { margin-left: auto; display: flex; align-items: center; gap: 2px; }
.site-nav a {
  color: var(--text-soft); text-decoration: none; font-size: 13.5px;
  padding: 8px 11px; border-radius: 999px;
  transition: color 140ms ease, background-color 140ms ease;
}
.site-nav a:hover { color: var(--text); background: var(--bg-raise); }

.header-actions { display: flex; align-items: center; gap: 8px; }

.icon-button {
  display: inline-flex; align-items: center; justify-content: center;
  width: 36px; height: 36px;
  border: 1px solid var(--line); border-radius: 999px;
  background: transparent; color: var(--text-soft); cursor: pointer;
  transition: color 140ms ease, border-color 140ms ease;
}
.icon-button:hover { color: var(--text); border-color: var(--line-strong); }

.theme-icon-sun { display: none; }
.theme-icon-moon { display: block; }
html[data-theme="light"] .theme-icon-sun { display: block; }
html[data-theme="light"] .theme-icon-moon { display: none; }
.theme-toggle svg { fill: none; stroke: currentColor; stroke-width: 1.6; stroke-linecap: round; }

.header-github {
  display: inline-flex; align-items: center; gap: 7px; height: 36px; padding-inline: 15px;
  border: 1px solid var(--line-strong); border-radius: 999px;
  background: var(--text); color: var(--bg);
  font-size: 13px; font-weight: 650; text-decoration: none;
  transition: opacity 140ms ease;
}
.header-github:hover { opacity: 0.85; }

.nav-toggle { display: none; position: relative; }
.nav-toggle span[aria-hidden] {
  position: absolute; left: 10px; width: 15px; height: 1.5px;
  background: currentColor; border-radius: 2px;
  transition: transform 200ms ease, top 200ms ease;
}
.nav-toggle span[aria-hidden]:first-of-type { top: 14px; }
.nav-toggle span[aria-hidden]:last-of-type { top: 20px; }
.nav-toggle[aria-expanded="true"] span[aria-hidden]:first-of-type { top: 17px; transform: rotate(45deg); }
.nav-toggle[aria-expanded="true"] span[aria-hidden]:last-of-type { top: 17px; transform: rotate(-45deg); }

.sr-only {
  position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; border: 0;
}

/* ---------- shared primitives ---------- */

.section { padding-block: 108px; }
.section-tight { padding-block: 76px; }

.eyebrow {
  display: inline-flex; align-items: center; gap: 9px;
  font: 620 11px/1 var(--font-mono);
  letter-spacing: 0.26em; text-transform: uppercase;
  color: var(--text-faint);
}
.eyebrow::before { content: "◆"; color: var(--accent); font-size: 8px; letter-spacing: 0; }
.status-dot { display: none; }

h1 { font-size: clamp(40px, 5.6vw, 68px); line-height: 1.03; letter-spacing: -0.032em; font-weight: 730; }
h2 { font-size: clamp(28px, 3.6vw, 42px); line-height: 1.08; letter-spacing: -0.022em; font-weight: 700; }
h3 { font-size: 17px; line-height: 1.35; font-weight: 650; }

.accent { color: var(--accent); font-style: italic; }

.section-heading { max-width: 680px; margin-bottom: 52px; }
.section-heading .eyebrow { margin-bottom: 18px; }
.section-heading h2 { margin-bottom: 14px; }
.section-heading p { color: var(--text-soft); font-size: 16px; }

.button {
  display: inline-flex; align-items: center; gap: 8px;
  border-radius: 999px; padding: 12px 22px;
  font-size: 14.5px; font-weight: 650; text-decoration: none;
  border: 1px solid transparent; cursor: pointer;
  transition: transform 140ms ease, opacity 140ms ease, border-color 140ms ease;
}
.button:hover { transform: translateY(-1px); }
.button:active { transform: translateY(0); }
.button-primary { background: var(--accent); color: var(--accent-ink); }
.button-primary:hover { opacity: 0.9; }
.button-secondary { background: transparent; color: var(--text); border-color: var(--line-strong); }
.button-secondary:hover { border-color: var(--text-faint); }
.button-ghost {
  background: none; border: none; padding: 12px 6px;
  font: 620 12px/1 var(--font-mono); letter-spacing: 0.18em; text-transform: uppercase;
  color: var(--text-soft); text-decoration: none;
  transition: color 140ms ease;
}
.button-ghost:hover { color: var(--accent); transform: none; }

.install-chip {
  display: flex; align-items: center; gap: 12px; max-width: 440px;
  border: 1px solid var(--line); border-radius: 999px;
  background: var(--bg-elev); padding: 10px 12px 10px 20px;
}
.install-chip .prompt-mark { color: var(--accent); font-family: var(--font-mono); font-size: 14px; }
.install-chip code { font-size: 13.5px; white-space: nowrap; overflow-x: auto; scrollbar-width: none; }

.copy-button {
  display: inline-flex; align-items: center; gap: 6px; margin-left: auto; flex: none;
  border: 1px solid var(--line); border-radius: 999px;
  background: var(--bg-raise); color: var(--text-soft);
  font: 550 12px/1 var(--font-sans); padding: 7px 12px; cursor: pointer;
  transition: color 140ms ease, border-color 140ms ease;
}
.copy-button:hover { color: var(--text); border-color: var(--line-strong); }
.copy-button.is-done { color: var(--accent); border-color: var(--accent); }
.copy-button svg { fill: none; stroke: currentColor; stroke-width: 1.7; stroke-linecap: round; stroke-linejoin: round; }

.text-link {
  display: inline-flex; align-items: center; gap: 6px;
  color: var(--accent); font-weight: 600; text-decoration: none;
  border-bottom: 1px solid transparent;
}
.text-link:hover { border-bottom-color: var(--accent); }

.compatibility { color: var(--text-faint); font: 500 12px/1.6 var(--font-mono); letter-spacing: 0.08em; text-transform: uppercase; margin-top: 16px; }

/* reveal animation — gated on html.js so content stays visible without JavaScript */
html.js [data-reveal] {
  opacity: 0; transform: translateY(16px);
  transition: opacity 600ms ease, transform 600ms cubic-bezier(0.22, 1, 0.36, 1);
}
html.js [data-reveal].is-visible { opacity: 1; transform: translateY(0); }

/* ---------- hero (landing, centered stage) ---------- */

.hero {
  position: relative; text-align: center;
  padding-block: 96px 40px;
}
.hero::before {
  content: ""; position: absolute; inset: -64px 0 auto; height: 620px; z-index: -1;
  background:
    linear-gradient(var(--grid-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-line) 1px, transparent 1px);
  background-size: 72px 72px;
  -webkit-mask-image: radial-gradient(60% 80% at 50% 0%, #000 30%, transparent 100%);
  mask-image: radial-gradient(60% 80% at 50% 0%, #000 30%, transparent 100%);
}
.hero::after {
  content: ""; position: absolute; inset: -120px 0 auto; height: 480px; z-index: -2;
  background: radial-gradient(46rem 22rem at 50% -20%, var(--accent-dim), transparent 72%);
}
.hero-copy { max-width: 780px; margin-inline: auto; }
.hero-copy h1 { margin: 22px 0 20px; }
.hero-lede { color: var(--text-soft); font-size: 17.5px; max-width: 40em; margin-inline: auto; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 14px; margin: 30px 0 22px; justify-content: center; align-items: center; }
.hero .install-chip { margin-inline: auto; }

.hero-stage { position: relative; max-width: 920px; margin: 64px auto 0; text-align: left; }
.goose-watermark {
  position: absolute; top: -78px; right: -8px; width: 200px; z-index: 1;
  filter: brightness(1.35) saturate(1.05) drop-shadow(0 16px 34px rgba(0, 0, 0, 0.5));
  pointer-events: none;
}

.float-chip {
  position: absolute; z-index: 2;
  background: var(--bg-elev); border: 1px solid var(--line-strong); border-radius: 12px;
  padding: 13px 16px; box-shadow: 0 18px 50px rgba(0, 0, 0, 0.45);
}
.float-chip strong { display: block; font: 700 22px/1.1 var(--font-sans); letter-spacing: -0.02em; }
.float-chip small { display: block; margin-top: 5px; font: 600 9.5px/1.5 var(--font-mono); letter-spacing: 0.14em; text-transform: uppercase; color: var(--text-faint); }
.float-chip-a { left: -108px; top: 84px; }
.float-chip-b { right: -96px; top: 178px; }
.float-chip-c { left: -76px; bottom: 96px; }

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

.terminal {
  position: relative; z-index: 1;
  border: 1px solid var(--line-strong); border-radius: var(--radius);
  background: var(--term-bg); color: var(--term-text);
  box-shadow: var(--shadow); overflow: hidden;
  font-family: var(--font-mono); font-size: 13.5px; line-height: 1.66;
}
.terminal-topbar {
  display: flex; align-items: center; gap: 10px; padding: 12px 16px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.06);
  color: #798088; font-size: 12px;
}
.terminal-dots { display: inline-flex; gap: 6px; }
.terminal-dots span { width: 10px; height: 10px; border-radius: 50%; background: #24282c; }
.terminal-dots span:nth-child(1) { background: #ff5f57; }
.terminal-dots span:nth-child(2) { background: #febc2e; }
.terminal-dots span:nth-child(3) { background: #28c840; }
.terminal-title { margin-inline: auto; }
.terminal-mode { font-weight: 700; letter-spacing: 0.14em; color: var(--term-accent); font-size: 10.5px; }

.terminal-tabs { display: flex; gap: 2px; padding: 10px 12px 0; border-bottom: 1px solid rgba(255, 255, 255, 0.06); }
.terminal-tabs [role="tab"] {
  border: 1px solid transparent; border-bottom: none;
  border-radius: 8px 8px 0 0; background: transparent;
  color: #798088; font: 500 12.5px/1 var(--font-mono);
  padding: 9px 14px; cursor: pointer;
}
.terminal-tabs [role="tab"]:hover { color: var(--term-text); }
.terminal-tabs [role="tab"][aria-selected="true"] {
  color: var(--term-accent);
  background: rgba(69, 232, 200, 0.06);
  border-color: rgba(255, 255, 255, 0.08);
}

.terminal-body { padding: 18px 22px 20px; min-height: 300px; }
.terminal-body p { margin: 0 0 4px; white-space: pre-wrap; }
.terminal-brand { color: var(--term-dim); }
.terminal-brand b { color: var(--term-accent); font-weight: 700; }
.terminal-prompt { color: var(--term-text); }
.terminal-prompt .mark { color: var(--term-accent); }
.terminal-context { color: var(--term-accent); }
.t-ok { color: var(--term-ok); }
.t-dim { color: var(--term-dim); }
.t-violet { color: var(--term-accent); }
.terminal-result {
  margin-top: 12px; border-left: 2px solid var(--term-accent);
  padding: 8px 0 8px 14px; color: var(--term-dim);
}
.terminal-result .who { color: var(--term-accent); font-weight: 700; }
.terminal-caret {
  display: inline-block; width: 8px; height: 15px;
  background: var(--term-accent); vertical-align: -2px;
  animation: caret-blink 1.1s steps(1) infinite;
}
@keyframes caret-blink { 50% { opacity: 0; } }

/* ---------- principles strip ---------- */

.proof-strip {
  display: grid; grid-template-columns: repeat(4, 1fr); gap: 18px;
  border-block: 1px solid var(--line);
  padding-block: 26px; margin-top: 88px;
}
.proof-strip p {
  display: flex; align-items: baseline; gap: 10px;
  color: var(--text-soft); font: 550 12px/1.5 var(--font-mono);
  letter-spacing: 0.1em; text-transform: uppercase;
}
.proof-strip span { color: var(--accent); font-weight: 700; }

/* ---------- stats band ---------- */

.stats-band {
  display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px;
  border-block: 1px solid var(--line); padding-block: 44px;
}
.stats-band > div { padding-inline: 6px; }
.stats-band strong {
  display: block; font-size: clamp(38px, 4.6vw, 56px);
  font-weight: 730; letter-spacing: -0.03em; line-height: 1;
}
.stats-band strong em { font-style: normal; color: var(--accent); }
.stats-band small {
  display: block; margin-top: 12px;
  font: 600 10px/1.7 var(--font-mono); letter-spacing: 0.16em;
  text-transform: uppercase; color: var(--text-faint); max-width: 22em;
}

/* ---------- workflow steps ---------- */

.workflow-grid { list-style: none; padding: 0; display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px; }
.workflow-grid li {
  border: 1px solid var(--line); border-radius: var(--radius);
  background: var(--surface); padding: 26px 22px;
}
.step-number { font: 650 12px/1 var(--font-mono); color: var(--accent); letter-spacing: 0.1em; }
.step-line { height: 1px; background: linear-gradient(90deg, var(--line-strong), transparent); margin: 16px 0 18px; }
.workflow-grid h3 { margin-bottom: 8px; }
.workflow-grid p { color: var(--text-soft); font-size: 14px; }
.step-tag {
  display: inline-block; margin-top: 18px;
  font: 620 9.5px/1 var(--font-mono); letter-spacing: 0.16em; text-transform: uppercase;
  color: var(--accent); background: var(--accent-dim);
  border-radius: 999px; padding: 7px 11px;
}

/* ---------- capability cards ---------- */

.capability-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; }
.capability-card {
  border: 1px solid var(--line); border-radius: var(--radius);
  background: var(--surface); padding: 28px 26px;
  display: flex; flex-direction: column; gap: 18px;
  transition: border-color 180ms ease;
}
.capability-card:hover { border-color: var(--line-strong); }
.capability-card-wide { grid-column: span 2; flex-direction: row; align-items: center; justify-content: space-between; gap: 30px; }
.card-kicker {
  font: 620 10px/1 var(--font-mono); letter-spacing: 0.22em; text-transform: uppercase;
  color: var(--accent); margin-bottom: 12px;
}
.capability-card h3 { margin-bottom: 8px; }
.capability-card p { color: var(--text-soft); font-size: 14px; }
.capability-card code { font-size: 12.5px; color: var(--text); }

.protocol-stack { display: grid; gap: 7px; flex: none; }
.protocol-stack span {
  display: flex; align-items: center; gap: 10px;
  border: 1px solid var(--line); border-radius: var(--radius-sm);
  background: var(--bg-elev); padding: 8px 14px 8px 8px;
  font: 500 12.5px/1 var(--font-mono); color: var(--text-soft); white-space: nowrap;
}
.protocol-stack i {
  font-style: normal; font-weight: 700; color: var(--accent);
  background: var(--accent-dim); border-radius: 7px;
  width: 23px; height: 23px; display: grid; place-items: center; font-size: 11.5px;
}

.mini-index { display: grid; gap: 7px; margin-top: auto; }
.mini-index span { height: 6px; border-radius: 3px; background: var(--bg-raise); position: relative; overflow: hidden; }
.mini-index span::after {
  content: ""; position: absolute; inset: 0; width: var(--score);
  border-radius: 3px;
  background: linear-gradient(90deg, var(--accent), color-mix(in srgb, var(--accent) 25%, transparent));
}

.output-pills { display: flex; gap: 7px; margin-top: auto; flex-wrap: wrap; }
.output-pills span {
  font: 550 11px/1 var(--font-mono); letter-spacing: 0.04em;
  color: var(--text-soft); border: 1px solid var(--line);
  border-radius: 999px; padding: 7px 11px; background: var(--bg-elev);
}

/* ---------- trust ---------- */

.trust { display: grid; grid-template-columns: 0.92fr 1.08fr; gap: 72px; align-items: center; }
.trust-visual { position: relative; aspect-ratio: 1; max-width: 400px; margin-inline: auto; width: 100%; }
.trust-ring { position: absolute; border: 1px dashed var(--line-strong); border-radius: 50%; }
.trust-ring-one { inset: 6%; }
.trust-ring-two { inset: 22%; border-style: solid; border-color: var(--line); }
.trust-core {
  position: absolute; inset: 37%;
  border: 1px solid var(--line-strong); border-radius: 50%;
  background: var(--bg-elev);
  display: grid; place-content: center; text-align: center; gap: 3px;
}
.trust-core span { color: var(--accent); font-size: 17px; }
.trust-core strong { font-size: 12px; letter-spacing: 0.02em; }
.trust-core small { color: var(--text-faint); font: 600 9px/1 var(--font-mono); letter-spacing: 0.14em; text-transform: uppercase; }
.trust-node {
  position: absolute;
  border: 1px solid var(--line-strong); border-radius: 999px;
  background: var(--bg-elev); padding: 8px 14px;
  font: 550 12px/1 var(--font-mono); color: var(--text-soft); white-space: nowrap;
  box-shadow: 0 12px 34px rgba(0, 0, 0, 0.4);
}
.trust-node b { font-weight: 700; margin-left: 6px; }
.trust-node-read { top: 2%; left: 50%; transform: translateX(-50%); }
.trust-node-read b { color: var(--term-ok); }
.trust-node-write { top: 47%; left: -3%; }
.trust-node-write b { color: var(--warn); }
.trust-node-shell { top: 47%; right: -3%; }
.trust-node-shell b { color: var(--warn); }
.trust-node-network { bottom: 2%; left: 50%; transform: translateX(-50%); }
.trust-node-network b { color: var(--danger); }

.trust-copy .eyebrow { margin-bottom: 18px; }
.trust-copy h2 { margin-bottom: 14px; }
.trust-copy > p { color: var(--text-soft); font-size: 15.5px; }

.check-list { list-style: none; padding: 0; margin: 28px 0 30px; display: grid; gap: 17px; }
.check-list li { display: flex; gap: 14px; align-items: flex-start; }
.check-list li > span {
  flex: none; width: 24px; height: 24px; border-radius: 999px;
  background: var(--accent-dim); color: var(--accent);
  display: grid; place-items: center; font-size: 12px; font-weight: 700;
}
.check-list strong { display: block; font-size: 14.5px; margin-bottom: 2px; }
.check-list small { color: var(--text-soft); font-size: 13.5px; }

/* ---------- dogfood ---------- */

.dogfood-card {
  display: grid; grid-template-columns: auto 1fr auto; gap: 30px; align-items: center;
  border: 1px solid var(--line); border-radius: 20px;
  background: linear-gradient(140deg, var(--accent-dim), transparent 55%), var(--surface);
  padding: 38px 40px;
}
.dogfood-mark {
  width: 50px; height: 50px; border-radius: 999px;
  border: 1px solid var(--line-strong);
  display: grid; place-items: center;
  color: var(--accent); font-size: 20px; background: var(--bg-elev);
}
.dogfood-card h2 { font-size: clamp(21px, 2.5vw, 27px); margin: 12px 0 8px; letter-spacing: -0.01em; }
.dogfood-card p { color: var(--text-soft); font-size: 14.5px; max-width: 52em; }
.dogfood-card blockquote { border-left: 2px solid var(--accent); padding-left: 18px; max-width: 250px; }
.dogfood-card blockquote p { color: var(--text); font-size: 14px; font-style: italic; }
.dogfood-card cite { display: block; margin-top: 8px; color: var(--text-faint); font: 600 9.5px/1.6 var(--font-mono); letter-spacing: 0.14em; text-transform: uppercase; font-style: normal; }

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

.quickstart-layout { display: grid; grid-template-columns: 300px 1fr; gap: 20px; align-items: start; }
.quickstart-steps { list-style: none; padding: 0; display: grid; gap: 8px; }
.quickstart-steps [role="tab"] {
  display: flex; align-items: center; gap: 14px; width: 100%; text-align: left;
  border: 1px solid var(--line); border-radius: 14px;
  background: var(--surface); color: var(--text-soft);
  padding: 15px 16px; cursor: pointer; font: inherit;
  transition: border-color 140ms ease;
}
.quickstart-steps [role="tab"]:hover { border-color: var(--line-strong); }
.quickstart-steps [role="tab"][aria-selected="true"] { border-color: var(--accent); color: var(--text); }
.quickstart-steps [role="tab"] > span {
  flex: none; width: 27px; height: 27px; border-radius: 999px;
  border: 1px solid var(--line-strong);
  display: grid; place-items: center;
  font: 620 12px/1 var(--font-mono); color: var(--accent);
}
.quickstart-steps strong { display: block; font-size: 14.5px; }
.quickstart-steps small { color: var(--text-faint); font-size: 12.5px; }

.code-window {
  border: 1px solid var(--line-strong); border-radius: var(--radius);
  background: var(--term-bg); overflow: hidden; box-shadow: var(--shadow);
}
.code-window-top {
  display: flex; justify-content: space-between; align-items: center;
  padding: 11px 16px; border-bottom: 1px solid rgba(255, 255, 255, 0.06);
  color: #798088; font: 600 10.5px/1 var(--font-mono); letter-spacing: 0.16em; text-transform: uppercase;
}
.code-window pre { padding: 18px 20px; overflow-x: auto; color: var(--term-text); font-size: 13.5px; line-height: 1.7; }
.code-comment { color: var(--term-dim); }

.quickstart-note { margin-top: 24px; color: var(--text-faint); font-size: 13.5px; max-width: 62em; }

/* ---------- guide page ---------- */

.guide-hero { position: relative; padding-block: 84px 24px; max-width: 760px; }
.guide-hero::before {
  content: ""; position: absolute; inset: -64px -40vw auto; height: 460px; z-index: -1;
  background:
    linear-gradient(var(--grid-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-line) 1px, transparent 1px);
  background-size: 72px 72px;
  -webkit-mask-image: radial-gradient(52% 78% at 30% 0%, #000 25%, transparent 100%);
  mask-image: radial-gradient(52% 78% at 30% 0%, #000 25%, transparent 100%);
}
.guide-hero h1 { margin: 22px 0 16px; font-size: clamp(34px, 4.6vw, 52px); }
.guide-hero p { color: var(--text-soft); font-size: 17px; }
.guide-hero .hero-actions { margin: 28px 0 0; justify-content: flex-start; }

.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; }
.info-card {
  border: 1px solid var(--line); border-radius: var(--radius);
  background: var(--surface); padding: 26px 24px;
}
.info-card .card-index { font: 650 12px/1 var(--font-mono); color: var(--accent); letter-spacing: 0.1em; }
.info-card h3 { margin: 14px 0 8px; }
.info-card p { color: var(--text-soft); font-size: 14px; }
.info-card code { font-size: 12.5px; color: var(--text); }

.table-wrap { overflow-x: auto; border: 1px solid var(--line); border-radius: var(--radius); background: var(--surface); }
table { width: 100%; border-collapse: collapse; font-size: 14px; min-width: 640px; }
th, td { padding: 13px 18px; text-align: left; border-bottom: 1px solid var(--line); vertical-align: top; }
tr:last-child td { border-bottom: none; }
th { color: var(--text-faint); font: 620 10.5px/1.5 var(--font-mono); text-transform: uppercase; letter-spacing: 0.14em; }
td:first-child { color: var(--text-soft); }
td code { font-size: 12.5px; color: var(--text); white-space: nowrap; }
td .soft { color: var(--text-faint); }
.status-good { color: var(--accent); font-weight: 650; }

.kbd-list { display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; list-style: none; padding: 0; }
.kbd-list li {
  display: flex; align-items: center; gap: 14px;
  border: 1px solid var(--line); border-radius: 14px;
  background: var(--surface); padding: 14px 16px;
  font-size: 13.5px; color: var(--text-soft);
}
kbd {
  flex: none; border: 1px solid var(--line-strong); border-bottom-width: 2px;
  border-radius: 7px; background: var(--bg-raise);
  padding: 5px 9px; font-size: 12px; color: var(--text); white-space: nowrap;
}

.invariant-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 14px; }
.invariant-card {
  display: flex; gap: 16px;
  border: 1px solid var(--line); border-radius: var(--radius);
  background: var(--surface); padding: 26px 24px;
}
.invariant-card .badge {
  flex: none; width: 34px; height: 34px; border-radius: 999px;
  background: var(--accent-dim); color: var(--accent);
  display: grid; place-items: center; font: 700 14px/1 var(--font-mono);
}
.invariant-card h3 { margin-bottom: 6px; }
.invariant-card p { color: var(--text-soft); font-size: 14px; }

.note-card {
  border: 1px solid var(--line); border-left: 2px solid var(--accent);
  border-radius: var(--radius-sm);
  background: var(--surface); padding: 16px 20px;
  color: var(--text-soft); font-size: 14px; margin-top: 20px;
}
.note-card code { color: var(--text); font-size: 12.5px; }

.stack-top { margin-top: 20px; }

/* ---------- faq ---------- */

.faq-list { display: grid; gap: 10px; max-width: 780px; }
.faq-list details { border: 1px solid var(--line); border-radius: 14px; background: var(--surface); }
.faq-list summary {
  cursor: pointer; list-style: none;
  display: flex; justify-content: space-between; align-items: center; gap: 14px;
  padding: 17px 20px; font-weight: 600; font-size: 14.5px;
}
.faq-list summary::-webkit-details-marker { display: none; }
.faq-list summary span[aria-hidden] { color: var(--accent); font-size: 17px; transition: transform 200ms ease; }
.faq-list details[open] summary span[aria-hidden] { transform: rotate(45deg); }
.faq-list details p { padding: 0 20px 17px; color: var(--text-soft); font-size: 14px; max-width: 62em; }
.faq-list details code { font-size: 12.5px; }

/* ---------- final cta ---------- */

.final-cta {
  position: relative; text-align: center;
  border: 1px solid var(--line); border-radius: 24px;
  background: var(--surface);
  padding: 72px 32px; margin-block: 40px 108px; overflow: hidden;
}
.final-cta::before {
  content: ""; position: absolute; inset: 0; z-index: 0;
  background:
    linear-gradient(var(--grid-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-line) 1px, transparent 1px);
  background-size: 64px 64px;
  -webkit-mask-image: radial-gradient(70% 90% at 50% 100%, #000 20%, transparent 100%);
  mask-image: radial-gradient(70% 90% at 50% 100%, #000 20%, transparent 100%);
}
.final-cta::after {
  content: ""; position: absolute; inset: auto 0 -40%; height: 70%; z-index: 0;
  background: radial-gradient(50% 100% at 50% 100%, var(--accent-dim), transparent 75%);
}
.final-cta > * { position: relative; z-index: 1; }
.final-cta img { width: 140px; margin-bottom: 10px; }
html[data-theme="light"] .final-cta img,
html[data-theme="light"] .error-page img { content: url("./assets/skein-goose.svg"); }
.final-cta .eyebrow { margin-bottom: 18px; }
.final-cta h2 { margin-bottom: 28px; }
.final-cta .hero-actions { justify-content: center; margin: 0; }

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

.site-footer { border-top: 1px solid var(--line); padding-block: 52px 40px; }
.footer-grid { display: grid; grid-template-columns: 1.2fr repeat(3, 0.8fr); gap: 32px; }
.footer-brand { display: flex; flex-direction: column; gap: 12px; align-items: flex-start; }
.footer-brand img { width: 38px; height: 27px; }
.footer-brand p { color: var(--text-faint); font-size: 13px; }
.footer-col strong {
  display: block; font: 620 10px/1 var(--font-mono);
  letter-spacing: 0.2em; text-transform: uppercase;
  color: var(--text-faint); margin-bottom: 16px;
}
.footer-col a { display: block; color: var(--text-soft); text-decoration: none; font-size: 13.5px; padding-block: 5px; }
.footer-col a:hover { color: var(--text); }
.footer-bottom {
  display: flex; justify-content: space-between; gap: 16px; flex-wrap: wrap;
  margin-top: 44px; padding-top: 24px; border-top: 1px solid var(--line);
  color: var(--text-faint); font-size: 12.5px;
}

/* ---------- toast ---------- */

.toast {
  position: fixed; left: 50%; bottom: 28px; transform: translate(-50%, 16px);
  background: var(--bg-raise); border: 1px solid var(--line-strong);
  color: var(--text); font-size: 13px;
  border-radius: 999px; padding: 10px 18px;
  opacity: 0; pointer-events: none;
  transition: opacity 220ms ease, transform 220ms ease; z-index: 60;
}
.toast.is-visible { opacity: 1; transform: translate(-50%, 0); }

/* ---------- 404 ---------- */

.error-page { min-height: 72vh; display: grid; place-content: center; text-align: center; gap: 14px; padding-block: 80px; }
.error-page img { width: 126px; margin-inline: auto; }
.error-code { font: 650 12px/1 var(--font-mono); color: var(--accent); letter-spacing: 0.22em; }
.error-page .hero-actions { justify-content: center; margin-top: 14px; }
.error-note { color: var(--text-soft); }

/* ---------- focus & motion ---------- */

a:focus-visible, button:focus-visible, summary:focus-visible, [role="tab"]:focus-visible {
  outline: 2px solid var(--accent); outline-offset: 2px; border-radius: 8px;
}

@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;
  }
  html.js [data-reveal] { opacity: 1; transform: none; }
  .terminal-caret { animation: none; }
}

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

@media (max-width: 1180px) {
  .float-chip-a { left: -12px; }
  .float-chip-b { right: -8px; }
  .float-chip-c { left: -4px; }
}

@media (max-width: 1020px) {
  .hero { padding-block: 64px 32px; }
  .hero-stage { margin-top: 48px; }
  .goose-watermark { top: -60px; width: 158px; }
  .float-chip { display: none; }
  .capability-grid { grid-template-columns: 1fr 1fr; }
  .capability-card-wide { grid-column: span 2; flex-direction: column; align-items: flex-start; }
  .trust { grid-template-columns: 1fr; gap: 44px; }
  .kbd-list { grid-template-columns: 1fr 1fr; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .stats-band { grid-template-columns: 1fr 1fr; row-gap: 36px; }
}

@media (max-width: 820px) {
  .section { padding-block: 72px; }
  .site-nav {
    position: absolute; top: 64px; left: 0; right: 0;
    flex-direction: column; align-items: stretch; gap: 2px;
    background: var(--bg-elev); border-bottom: 1px solid var(--line);
    padding: 10px 16px 16px; display: none;
  }
  .site-nav.is-open { display: flex; }
  .site-nav a { padding: 12px 14px; font-size: 15px; border-radius: 10px; }
  .nav-toggle { display: inline-flex; }
  .header-github { display: none; }
  .proof-strip { grid-template-columns: 1fr 1fr; }
  .workflow-grid { grid-template-columns: 1fr 1fr; }
  .quickstart-layout { grid-template-columns: 1fr; }
  .quickstart-steps { grid-template-columns: repeat(3, 1fr); }
  .quickstart-steps strong { font-size: 13px; }
  .quickstart-steps small { display: none; }
  .quickstart-steps [role="tab"] { flex-direction: column; gap: 8px; text-align: center; padding: 12px 8px; }
  .dogfood-card { grid-template-columns: 1fr; gap: 20px; }
  .dogfood-card blockquote { max-width: none; }
  .invariant-grid { grid-template-columns: 1fr; }
  .grid-3 { grid-template-columns: 1fr; }
}

@media (max-width: 620px) {
  .section { padding-block: 60px; }
  .proof-strip { grid-template-columns: 1fr; gap: 12px; }
  .stats-band { grid-template-columns: 1fr; }
  .workflow-grid { grid-template-columns: 1fr; }
  .capability-grid { grid-template-columns: 1fr; }
  .capability-card-wide { grid-column: auto; }
  .kbd-list { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; }
  .hero-actions .button { width: 100%; justify-content: center; }
  .install-chip { max-width: none; }
  .goose-watermark { display: none; }
  .quickstart-steps { grid-template-columns: 1fr; }
  .quickstart-steps [role="tab"] { flex-direction: row; text-align: left; }
  .final-cta { padding: 52px 20px; }
}