:root {
  --bg: #0d1117;
  --bg-alt: #161b22;
  --surface: #21262d;
  --text: #e6edf3;
  --muted: #8b949e;
  --accent: #58a6ff;
  --accent-dim: #388bfd44;
  --border: #30363d;
  --ok: #3fb950;
  --warn: #d29922;
  --danger: #f85149;
  --ink: #0d1117;
  font-size: 16px;
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: "Inter", "Segoe UI", system-ui, -apple-system, sans-serif;
  line-height: 1.6;
  color: var(--text);
  background: var(--bg);
}

a {
  color: var(--accent);
  text-decoration-thickness: 0.08em;
  text-underline-offset: 0.12em;
}

a:hover {
  text-decoration: none;
}

.skip-link {
  position: absolute;
  left: -9999px;
  z-index: 100;
  padding: 0.5rem 1rem;
  background: var(--accent);
  color: var(--ink);
}

.skip-link:focus {
  left: 0.5rem;
  top: 0.5rem;
}

.wrap {
  max-width: 68rem;
  margin: 0 auto;
  padding: 0 1.25rem;
}

/* Header / nav */
.site-header {
  border-bottom: 1px solid var(--border);
  background: rgba(13, 17, 23, 0.9);
  backdrop-filter: blur(8px);
  position: sticky;
  top: 0;
  z-index: 50;
}

.header-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.75rem 0;
}

.logo {
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--text);
  text-decoration: none;
  letter-spacing: 0.02em;
}

.nav ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1rem;
}

.nav a {
  color: var(--muted);
  text-decoration: none;
  font-size: 0.9rem;
}

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

/* Main */
.main {
  min-height: 50vh;
  padding-bottom: 4rem;
}

/* Hero */
.hero {
  padding: 4rem 0 3.5rem;
  background: radial-gradient(ellipse 80% 60% at 50% -20%, var(--accent-dim), transparent),
    var(--bg);
  border-bottom: 1px solid var(--border);
}

.hero .eyebrow {
  text-transform: uppercase;
  letter-spacing: 0.15em;
  font-size: 0.75rem;
  color: var(--muted);
  margin: 0 0 0.75rem;
}

.hero h1 {
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  line-height: 1.15;
  margin: 0 0 0.75rem;
  font-weight: 700;
}

.tagline {
  font-size: 1.15rem;
  color: var(--muted);
  margin: 0 0 2rem;
  max-width: 36rem;
}

.cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.55rem 1.1rem;
  border-radius: 6px;
  border: 1px solid var(--border);
  color: var(--text);
  font-weight: 500;
  font-size: 0.95rem;
  text-decoration: none;
  background: var(--bg-alt);
}

.btn:hover {
  border-color: var(--muted);
  background: var(--surface);
}

.btn.primary {
  background: var(--accent);
  color: var(--ink);
  border-color: transparent;
}

.btn.primary:hover {
  filter: brightness(1.08);
}

/* Bands */
.band {
  padding: 3rem 0;
}

.band-alt {
  background: var(--bg-alt);
  border-block: 1px solid var(--border);
}

.center {
  text-align: center;
}

.three-col {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(15rem, 1fr));
  gap: 1.5rem;
  list-style: none;
  margin: 0;
  padding: 0;
}

.three-col h3 {
  margin: 0 0 0.5rem;
  font-size: 1.05rem;
}

.three-col p {
  margin: 0;
  color: var(--muted);
  font-size: 0.95rem;
}

/* Prose */
.prose {
  padding-top: 2.5rem;
}

.page-head h1,
.spec-head h1 {
  margin-top: 0;
  font-size: 2rem;
}

.lead {
  font-size: 1.1rem;
  color: var(--muted);
  margin-top: 0;
}

.prose h2 {
  margin-top: 2rem;
  padding-bottom: 0.35rem;
  border-bottom: 1px solid var(--border);
  font-size: 1.35rem;
}

.prose h3 {
  margin-top: 1.5rem;
  font-size: 1.1rem;
}

.prose pre {
  background: var(--bg-alt);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1rem;
  overflow-x: auto;
}

.prose code {
  font-family: "JetBrains Mono", "Fira Code", ui-monospace, monospace;
  font-size: 0.9em;
}

.prose table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.95rem;
}

.prose th,
.prose td {
  border: 1px solid var(--border);
  padding: 0.5rem 0.75rem;
  text-align: left;
}

.prose th {
  background: var(--bg-alt);
}

.meta {
  color: var(--muted);
  font-size: 0.9rem;
}

.muted {
  color: var(--muted);
}

/* Spec doc */
.spec-page .spec-head {
  margin-bottom: 1rem;
}

.spec-id {
  font-family: ui-monospace, monospace;
  color: var(--muted);
  margin: 0 0 0.25rem;
  font-size: 0.9rem;
}

.spec-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.75rem 1rem;
  margin: 1rem 0;
}

.meta-item {
  font-size: 0.9rem;
  color: var(--muted);
}

.authors {
  font-size: 0.95rem;
  color: var(--muted);
}

.downloads {
  margin: 2rem 0;
  padding: 1rem 1.25rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--bg-alt);
}

.downloads h2 {
  margin: 0 0 0.75rem;
  font-size: 1rem;
}

.downloads ul {
  margin: 0;
  padding-left: 1.2rem;
}

/* Badges */
.badge {
  display: inline-block;
  padding: 0.2rem 0.55rem;
  border-radius: 999px;
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  background: var(--surface);
  border: 1px solid var(--border);
}

.badge-final {
  background: rgba(63, 185, 80, 0.15);
  border-color: rgba(63, 185, 80, 0.45);
  color: var(--ok);
}

.badge-proposed {
  background: rgba(88, 166, 255, 0.12);
  border-color: rgba(88, 166, 255, 0.4);
  color: var(--accent);
}

.badge-draft {
  background: rgba(210, 153, 34, 0.12);
  border-color: rgba(210, 153, 34, 0.45);
  color: var(--warn);
}

.badge-experimental {
  background: rgba(248, 81, 73, 0.1);
  border-color: rgba(248, 81, 73, 0.35);
  color: #ff7b72;
}

.badge-obsolete {
  background: var(--surface);
  color: var(--muted);
}

/* Specs index */
.specs-page .spec-diagram {
  margin: 1rem 0;
}

.category-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(18rem, 1fr));
  gap: 1rem;
}

.category-grid dt {
  font-weight: 600;
  margin-bottom: 0.25rem;
}

.category-grid dd {
  margin: 0;
  color: var(--muted);
  font-size: 0.95rem;
}

.spec-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.92rem;
}

.spec-table th,
.spec-table td {
  border: 1px solid var(--border);
  padding: 0.5rem 0.65rem;
  vertical-align: top;
}

.spec-table th {
  background: var(--bg-alt);
  text-align: left;
}

.spec-states {
  margin-bottom: 2.5rem;
}

/* Footer */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 2rem 0;
  margin-top: auto;
  background: var(--bg-alt);
  font-size: 0.9rem;
  color: var(--muted);
}

.footer-inner p {
  margin: 0.25rem 0;
}

.footer-links a {
  color: var(--muted);
}

@media print {
  .site-header,
  .site-footer,
  .downloads,
  .nav {
    display: none;
  }

  body {
    background: white;
    color: black;
  }
}