:root {
  /* Light theme — the default */
  --bg: #ffffff;
  --panel: #f5f7fa;
  --border: #e2e7ef;
  --fg: #1a2230;
  --muted: #59647a;
  --accent: #2f6fe0;
  --accent-2: #6d5ae6;
  --grad: linear-gradient(135deg, #6ea8fe 0%, #9d7bff 100%);
  --title-grad: linear-gradient(135deg, #141a24 0%, #5a3bd0 100%);
  --error: #d23f3c;
  --warn: #a9790f;
  --info: #6a7a8c;
  --mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, monospace;
}

[data-theme="dark"] {
  --bg: #0d1117;
  --panel: #161b22;
  --border: #283041;
  --fg: #e6edf3;
  --muted: #8b97a7;
  --accent: #6ea8fe;
  --accent-2: #6d5ae6;
  --title-grad: linear-gradient(135deg, #ffffff 0%, #9db8ff 100%);
  --error: #f0716f;
  --warn: #e3b341;
  --info: #6a7a8c;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  line-height: 1.6;
  transition: background-color 0.2s ease, color 0.2s ease;
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
code { font-family: var(--mono); }

.site-header, .site-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem 2rem;
  border-bottom: 1px solid var(--border);
  flex-wrap: wrap;
  gap: 1rem;
}
.site-footer {
  border-top: 1px solid var(--border);
  border-bottom: none;
  color: var(--muted);
  font-size: 0.85rem;
  margin-top: 4rem;
}
.brand { font-weight: 700; font-size: 1.2rem; color: var(--fg); display: inline-flex; align-items: center; gap: 0.5rem; }
.brand:hover { text-decoration: none; }
.brand-mark { display: block; flex: none; }
.site-header nav { display: flex; gap: 1.5rem; }
.site-header nav a { color: var(--muted); padding-bottom: 2px; }
.site-header nav a:hover { color: var(--fg); text-decoration: none; }
.site-header nav a.active { color: var(--fg); border-bottom: 2px solid var(--accent); }
.gh-link { display: inline-flex; align-items: center; }
.gh-link:hover { border-bottom: none; }

main { max-width: 1040px; margin: 0 auto; padding: 0 2rem; }

.hero { padding: 5rem 0 2.5rem; position: relative; }
.hero::before {
  content: ""; position: absolute; inset: -10% -25% auto -25%; height: 440px; z-index: -1;
  background: radial-gradient(55% 60% at 30% 0%, rgba(110,168,254,0.18), transparent 70%);
  pointer-events: none;
}
.hero h1 {
  font-size: 3.5rem; margin: 0 0 1.25rem; letter-spacing: -0.03em; line-height: 1.12; font-weight: 800;
  padding-bottom: 0.08em;
  background: var(--title-grad);
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.lead { font-size: 1.4rem; font-weight: 600; color: var(--fg); max-width: 62ch; margin: 0 0 0.85rem; line-height: 1.4; }
.tagline { font-size: 1.12rem; color: var(--muted); max-width: 70ch; }
.tagline strong { color: var(--fg); }
.cta { display: flex; align-items: center; gap: 1.5rem; margin: 2rem 0; flex-wrap: wrap; }
.cta code {
  background: var(--panel); border: 1px solid var(--border);
  padding: 0.6rem 1rem; border-radius: 8px; font-size: 1rem;
}
.btn {
  background: var(--grad); color: #fff; padding: 0.65rem 1.3rem;
  border-radius: 8px; font-weight: 600; border: 1px solid transparent;
}
.btn:hover { text-decoration: none; filter: brightness(1.1); }
.btn.ghost { background: transparent; color: var(--accent-2); border: 1px solid var(--border); }
.btn.ghost:hover { border-color: var(--accent-2); filter: none; }
.callout {
  display: flex; gap: 0.9rem; align-items: flex-start; max-width: 72ch; margin: 2rem 0;
  background: var(--panel); border: 1px solid var(--border); border-left: 3px solid var(--accent-2);
  border-radius: 10px; padding: 0.9rem 1.2rem;
}
.callout-mark { font-size: 1.7rem; line-height: 1; color: var(--accent-2); flex: none; margin-top: 0.05rem; }
.callout p { margin: 0; color: var(--muted); font-size: 0.97rem; }
.callout em { color: var(--fg); }
.callout code { color: var(--fg); }

/* hero "log -> record" visual */
.transform {
  display: grid; grid-template-columns: 1fr auto 1fr; align-items: center;
  gap: 1.25rem; margin: 2.5rem 0 1rem;
}
.t-panel {
  background: var(--panel); border: 1px solid var(--border);
  border-radius: 12px; padding: 1rem 1.15rem;
}
.t-record { border-color: var(--accent); box-shadow: 0 0 0 1px var(--accent) inset; }
.t-label {
  font-size: 0.7rem; text-transform: uppercase; letter-spacing: 0.08em;
  color: var(--muted); margin-bottom: 0.8rem;
}
.t-lines { font-family: var(--mono); font-size: 0.82rem; color: var(--muted); line-height: 1.85; }
.t-lines .u { color: var(--accent); margin-right: 0.5rem; }
.t-lines .a { color: var(--muted); opacity: 0.7; margin-right: 0.5rem; }
.t-arrow { color: var(--accent-2); font-size: 1.8rem; font-weight: 700; }
.t-steps { display: flex; flex-direction: column; gap: 0.6rem; }
.t-step { display: flex; align-items: center; gap: 0.5rem; font-size: 0.92rem; line-height: 1.3; }
.t-dot { width: 9px; height: 9px; border-radius: 50%; background: var(--grad); flex: none; }
.t-step.gap { color: var(--muted); }
.t-warn { color: var(--warn); flex: none; font-size: 0.8rem; }
.t-badge {
  margin-left: auto; font-size: 0.66rem; padding: 0.12rem 0.55rem;
  border-radius: 999px; flex: none; font-weight: 600;
}
.t-badge.ok { background: rgba(46,160,67,0.16); color: #2da44e; }
.t-badge.proved { background: rgba(110,168,254,0.16); color: var(--accent); }
.t-badge.gap { background: rgba(169,121,15,0.16); color: var(--warn); }
.t-foot {
  margin-top: 0.95rem; padding-top: 0.7rem; border-top: 1px solid var(--border);
  font-size: 0.82rem; color: var(--muted);
}
.t-grade { color: var(--fg); font-weight: 700; }
@media (max-width: 760px) {
  .transform { grid-template-columns: 1fr; }
  .t-arrow { transform: rotate(90deg); justify-self: center; }
}

.grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1rem; margin: 2rem 0;
}
.grid article {
  background: var(--panel); border: 1px solid var(--border);
  border-radius: 12px; padding: 1.4rem; position: relative;
  transition: transform .15s ease, border-color .15s ease;
}
.grid article:hover { transform: translateY(-3px); border-color: var(--accent); }
.grid h3 { margin: 0 0 0.5rem; font-size: 1.08rem; }
.grid p { color: var(--muted); margin: 0; font-size: 0.95rem; }

.quickstart { margin: 3.5rem 0; }
.quickstart pre {
  background: var(--panel); border: 1px solid var(--border);
  border-radius: 12px; padding: 1.5rem; overflow-x: auto; position: relative;
}
.quickstart pre::before {
  content: "● ● ●"; position: absolute; top: 0.8rem; left: 1.3rem;
  color: var(--border); font-size: 0.7rem; letter-spacing: 0.25rem;
}
.quickstart pre code { color: var(--fg); display: block; margin-top: 1.1rem; }

/* Gallery */
.gallery-head { padding: 2.5rem 0 1rem; }
#q {
  width: 100%; margin-top: 1rem; padding: 0.7rem 1rem;
  background: var(--panel); border: 1px solid var(--border);
  border-radius: 8px; color: var(--fg); font-size: 1rem;
}
.filters { display: flex; gap: 0.5rem; flex-wrap: wrap; margin-top: 1rem; }
.chip {
  background: var(--panel); border: 1px solid var(--border); color: var(--muted);
  padding: 0.3rem 0.8rem; border-radius: 999px; cursor: pointer; font-size: 0.85rem;
}
.chip.active { color: var(--fg); border-color: var(--accent); }
.count { color: var(--muted); font-size: 0.85rem; margin: 1rem 0; }

.policy-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1rem;
}
.policy-card {
  background: var(--panel); border: 1px solid var(--border);
  border-radius: 12px; padding: 1.1rem;
}
.policy-top { display: flex; justify-content: space-between; align-items: flex-start; gap: 0.6rem; }
.pid { color: var(--accent); font-size: 0.8rem; min-width: 0; overflow-wrap: anywhere; line-height: 1.4; }
.policy-card h3 { margin: 0.6rem 0 0.4rem; font-size: 1.05rem; }
.policy-card p { color: var(--muted); font-size: 0.9rem; margin: 0 0 0.8rem; }
.policy-meta { display: flex; gap: 0.4rem; flex-wrap: wrap; align-items: center; }
.dom { color: var(--fg); font-size: 0.8rem; }
.tag {
  background: var(--bg); border: 1px solid var(--border); color: var(--muted);
  padding: 0.1rem 0.5rem; border-radius: 6px; font-size: 0.75rem;
}

/* theme toggle */
.theme-toggle {
  background: none; border: none; color: var(--muted); cursor: pointer; padding: 0;
  display: inline-flex; align-items: center;
}
.theme-toggle:hover { color: var(--fg); }
.theme-toggle .t-sun { display: none; }
[data-theme="dark"] .theme-toggle .t-moon { display: none; }
[data-theme="dark"] .theme-toggle .t-sun { display: inline-flex; }
.sev { font-size: 0.75rem; padding: 0.15rem 0.55rem; border-radius: 6px; font-weight: 600; flex: none; white-space: nowrap; }
.sev-error { background: rgba(240,113,111,0.15); color: var(--error); }
.sev-warning { background: rgba(227,179,65,0.15); color: var(--warn); }
.sev-info { background: rgba(106,122,140,0.2); color: var(--muted); }
.status { font-size: 0.72rem; padding: 0.15rem 0.55rem; border-radius: 999px; font-weight: 600; flex: none; white-space: nowrap; }
.status-available { background: rgba(46,160,67,0.16); color: #2da44e; }
.status-community { background: rgba(110,168,254,0.16); color: var(--accent); }
.status-experimental { background: rgba(227,179,65,0.16); color: var(--warn); }
.status-planned { background: var(--panel); color: var(--muted); border: 1px solid var(--border); }
.muted-note { color: var(--muted); font-size: 0.9rem; }
.empty { color: var(--muted); }
.policy-card { text-decoration: none; color: inherit; display: block; }
.policy-card:hover { border-color: var(--accent); text-decoration: none; }

/* page heads */
.page-head { padding: 2.5rem 0 1rem; }
.page-head h1 { margin: 0 0 0.5rem; letter-spacing: -0.02em; }
.page-head p { color: var(--muted); max-width: 70ch; }

/* docs page: left section menu + content */
.docs-layout { display: grid; grid-template-columns: 170px minmax(0, 1fr); gap: 2.5rem; align-items: start; }
.docs-layout .prose { margin: 0; max-width: 74ch; }
.docs-nav { position: sticky; top: 1.5rem; align-self: start; padding-top: 2.4rem; }
.docs-nav-title { font-size: 0.68rem; text-transform: uppercase; letter-spacing: 0.08em; color: var(--muted); margin: 0 0 0.6rem 0.7rem; }
.docs-nav nav { display: flex; flex-direction: column; gap: 0.1rem; }
.docs-nav a { font-size: 0.88rem; color: var(--muted); padding: 0.28rem 0.7rem; border-left: 2px solid var(--border); }
.docs-nav a:hover { color: var(--fg); text-decoration: none; }
.docs-nav a.active { color: var(--fg); border-left-color: var(--accent); font-weight: 600; }
@media (max-width: 820px) {
  .docs-layout { grid-template-columns: 1fr; gap: 0; }
  .docs-nav { position: static; padding-top: 0; margin-bottom: 1.25rem; }
  .docs-nav nav { flex-direction: row; flex-wrap: wrap; gap: 0.4rem; }
  .docs-nav a { border-left: none; border: 1px solid var(--border); border-radius: 999px; }
  .docs-nav a.active { border-color: var(--accent); }
}

/* prose (docs + spec markdown) */
.prose { max-width: 80ch; margin: 0 auto; padding: 2rem 0 1rem; }
.prose h1 { letter-spacing: -0.02em; margin: 1.5rem 0 1rem; }
.prose h2 { margin: 2rem 0 0.75rem; border-bottom: 1px solid var(--border); padding-bottom: 0.3rem; }
.prose h3 { margin: 1.5rem 0 0.5rem; }
.prose p, .prose li { color: var(--fg); }
.prose code { background: var(--panel); border: 1px solid var(--border); padding: 0.1rem 0.35rem; border-radius: 5px; font-size: 0.9em; }
.prose pre { background: var(--panel); border: 1px solid var(--border); border-radius: 10px; padding: 1rem 1.25rem; overflow-x: auto; }
.prose pre code { background: none; border: none; padding: 0; }
.prose table { border-collapse: collapse; width: 100%; margin: 1rem 0; font-size: 0.92rem; }
.prose th, .prose td { border: 1px solid var(--border); padding: 0.5rem 0.7rem; text-align: left; vertical-align: top; }
.prose th { background: var(--panel); }
.prose blockquote { border-left: 3px solid var(--accent-2); margin: 1rem 0; padding: 0.3rem 0 0.3rem 1rem; color: var(--muted); }
.spec-back { font-size: 0.85rem; }
.spec-back a { color: var(--muted); }

/* spec index */
.spec-list { list-style: none; padding: 0; max-width: 760px; }
.spec-list li { display: flex; align-items: baseline; justify-content: space-between; gap: 1rem;
  padding: 0.8rem 1rem; border: 1px solid var(--border); border-radius: 10px; margin-bottom: 0.6rem; background: var(--panel); }
.spec-list a { font-weight: 600; }
.spec-list code { color: var(--muted); font-size: 0.8rem; }

/* policy detail */
.policy-detail { max-width: 80ch; margin: 0 auto; padding: 2rem 0; }
.pd-head { display: flex; align-items: center; gap: 1rem; }
.pd-head h1 { margin: 0; }
.pd-id { color: var(--muted); margin: 0.2rem 0 0.6rem; }
.pd-meta { display: flex; flex-wrap: wrap; gap: 0.4rem; align-items: center; margin-bottom: 1rem; }
.pd-meta .cat, .pd-meta .lvl { color: var(--muted); font-size: 0.8rem; }
.pd-desc { font-size: 1.05rem; }
.policy-detail h2 { margin: 1.75rem 0 0.6rem; font-size: 1.05rem; color: var(--muted); text-transform: uppercase; letter-spacing: 0.05em; }
.formula { background: var(--panel); border: 1px solid var(--border); border-radius: 10px; padding: 1rem 1.25rem; overflow-x: auto; font-size: 1.05rem; }
.usage { background: var(--panel); border: 1px solid var(--border); border-radius: 10px; padding: 1rem 1.25rem; overflow-x: auto; }
.ex { font-size: 0.95rem; }
.ex-pass strong { color: #56d364; } .ex-fail strong { color: var(--error); }

/* viewer */
.viewer-frame { border: 1px solid var(--border); border-radius: 12px; overflow: hidden; height: 78vh; background: #0d1117; }
.viewer-frame iframe { width: 100%; height: 100%; border: 0; display: block; }
.viewer-note { color: var(--muted); font-size: 0.9rem; margin-top: 0.8rem; }