:root {
    --bg: #121016;
    --surface: #1C1821;
    --surface-2: #241F2B;
    --line: #332C3A;
    --text: #F1EBE0;
    --text-dim: #A79C8E;
    --text-faint: #6E6577;
    --accent: #E3A83B;
    --accent-soft: #7A5A22;
    --accent-ink: #2A1D06;
    --red: #B5432C;
  }

  @media (prefers-color-scheme: light) {
    :root:not([data-theme="light"]) {
      --bg: #F6F1E6;
      --surface: #FFFFFF;
      --surface-2: #EFE7D6;
      --line: #DDD2B8;
      --text: #241E17;
      --text-dim: #5B5245;
      --text-faint: #8A8071;
      --accent: #B5792A;
      --accent-soft: #E9CE9C;
      --accent-ink: #FBF3E0;
      --red: #A13B25;
    }
  }
  :root[data-theme="light"] {
    --bg: #F6F1E6;
    --surface: #FFFFFF;
    --surface-2: #EFE7D6;
    --line: #DDD2B8;
    --text: #241E17;
    --text-dim: #5B5245;
    --text-faint: #8A8071;
    --accent: #B5792A;
    --accent-soft: #E9CE9C;
    --accent-ink: #FBF3E0;
    --red: #A13B25;
  }

  * { box-sizing: border-box; }

  body {
    margin: 0;
    background: var(--bg);
    color: var(--text);
    font-family: -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
  }

  .display {
    font-family: "Iowan Old Style", "Palatino Linotype", Palatino, Georgia, "Times New Roman", serif;
  }

  a { color: inherit; }

  .wrap {
    max-width: 1080px;
    margin: 0 auto;
    padding: 0 clamp(20px, 5vw, 56px);
  }

  /* ---------- reel rule divider ---------- */
  .reel {
    height: 22px;
    background-image: radial-gradient(circle, var(--line) 2.5px, transparent 2.6px);
    background-size: 26px 22px;
    background-position: center;
    opacity: 0.7;
  }

  /* ---------- header ---------- */
  header {
    position: sticky;
    top: 0;
    z-index: 20;
    background: color-mix(in srgb, var(--bg) 88%, transparent);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--line);
  }
  header .wrap {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 68px;
  }
  .brand {
    display: flex;
    align-items: baseline;
    gap: 0.5rem;
    font-size: 1.15rem;
    letter-spacing: 0.02em;
    font-weight: 600;
    text-decoration: none;
  }
  .brand .mark { color: var(--accent); font-style: italic; }
  nav.links {
    display: flex;
    gap: 2rem;
    font-size: 0.9rem;
    color: var(--text-dim);
  }
  nav.links a { text-decoration: none; transition: color .15s ease; }
  nav.links a:hover, nav.links a:focus-visible { color: var(--accent); }
  @media (max-width: 720px) { nav.links { display: none; } }

  /* ---------- hero ---------- */
  .hero {
    padding: clamp(56px, 8vw, 108px) 0 clamp(48px, 8vw, 84px);
    position: relative;
    overflow: hidden;
  }
  .hero::before {
    content: "";
    position: absolute;
    inset: -20% -10% auto -10%;
    height: 480px;
    background: radial-gradient(ellipse at 30% 0%, color-mix(in srgb, var(--accent) 20%, transparent), transparent 65%);
    pointer-events: none;
  }
  .eyebrow {
    display: inline-flex;
    align-items: center;
    gap: 0.55rem;
    font-size: 0.78rem;
    letter-spacing: 0.14em;
    text-transform: uppercase;
    color: var(--accent);
    border: 1px solid var(--accent-soft);
    background: var(--accent-ink);
    padding: 0.4rem 0.85rem;
    border-radius: 999px;
  }
  .eyebrow .dot { width: 6px; height: 6px; border-radius: 50%; background: var(--red); }

  h1 {
    margin: 1.3rem 0 0;
    font-weight: 500;
    font-size: clamp(2.6rem, 6vw, 4.4rem);
    line-height: 1.03;
    text-wrap: balance;
    letter-spacing: -0.01em;
  }
  h1 em {
    font-style: italic;
    color: var(--accent);
  }

  .lede {
    margin: 1.6rem 0 0;
    max-width: 620px;
    font-size: 1.1rem;
    color: var(--text-dim);
  }

  .cta-row {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    margin-top: 2.4rem;
  }
  .btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.85rem 1.5rem;
    border-radius: 8px;
    font-size: 0.95rem;
    font-weight: 600;
    text-decoration: none;
    border: 1px solid transparent;
    cursor: pointer;
    transition: transform .15s ease, background .15s ease, border-color .15s ease;
  }
  .btn:hover { transform: translateY(-1px); }
  .btn-primary { background: var(--accent); color: var(--accent-ink); }
  .btn-primary:hover { background: color-mix(in srgb, var(--accent) 90%, white 10%); }
  .btn-ghost { border-color: var(--line); color: var(--text); }
  .btn-ghost:hover { border-color: var(--accent); color: var(--accent); }
  .btn:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }

  .meta-strip {
    margin-top: 3.4rem;
    display: flex;
    flex-wrap: wrap;
    gap: clamp(1.5rem, 4vw, 3rem);
    color: var(--text-faint);
    font-size: 0.82rem;
  }
  .meta-strip strong {
    display: block;
    color: var(--text);
    font-size: 0.95rem;
    font-weight: 600;
  }

  /* ---------- section shell ---------- */
  section { padding: clamp(56px, 9vw, 92px) 0; }
  .section-head { max-width: 640px; margin-bottom: clamp(2.2rem, 5vw, 3.2rem); }
  .kicker {
    font-size: 0.78rem;
    letter-spacing: 0.14em;
    text-transform: uppercase;
    color: var(--text-faint);
    margin: 0 0 0.7rem;
  }
  .kicker::before { content: "— "; color: var(--accent); }
  h2 {
    margin: 0;
    font-weight: 500;
    font-size: clamp(1.8rem, 3.4vw, 2.5rem);
    text-wrap: balance;
  }
  .section-head p { color: var(--text-dim); margin: 0.9rem 0 0; }

  /* ---------- feature grid ---------- */
  .grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 1px;
    background: var(--line);
    border: 1px solid var(--line);
    border-radius: 14px;
    overflow: hidden;
  }
  .card {
    background: var(--surface);
    padding: 1.9rem;
  }
  .card .num {
    font-size: 0.75rem;
    color: var(--accent);
    letter-spacing: 0.08em;
    font-weight: 700;
  }
  .card h3 {
    margin: 0.9rem 0 0.5rem;
    font-size: 1.08rem;
    font-weight: 600;
  }
  .card p { margin: 0; color: var(--text-dim); font-size: 0.92rem; }

  /* ---------- endpoints ---------- */
  .panel {
    border: 1px solid var(--line);
    border-radius: 14px;
    background: var(--surface);
    overflow: hidden;
  }
  .panel-head {
    display: flex;
    align-items: center;
    gap: 0.6rem;
    padding: 0.9rem 1.2rem;
    background: var(--surface-2);
    border-bottom: 1px solid var(--line);
    font-size: 0.82rem;
    color: var(--text-faint);
  }
  .panel-head .dot { width: 9px; height: 9px; border-radius: 50%; }
  .panel-head .dot:nth-child(1) { background: var(--red); }
  .panel-head .dot:nth-child(2) { background: var(--accent); }
  .panel-head .dot:nth-child(3) { background: color-mix(in srgb, var(--text-faint) 60%, transparent); }
  .panel-head span.file { margin-left: 0.5rem; font-family: ui-monospace, "SF Mono", Menlo, monospace; }

  .endpoint {
    display: grid;
    grid-template-columns: 72px 1fr auto;
    align-items: center;
    gap: 1rem;
    padding: 1rem 1.2rem;
    border-bottom: 1px solid var(--line);
    font-family: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
    font-size: 0.88rem;
  }
  .endpoint:last-child { border-bottom: none; }
  .verb {
    text-align: center;
    padding: 0.25rem 0;
    border-radius: 5px;
    font-size: 0.72rem;
    font-weight: 700;
    letter-spacing: 0.03em;
  }
  .verb.get { background: color-mix(in srgb, #4E8F6C 22%, transparent); color: #6FBE94; }
  .verb.post { background: color-mix(in srgb, var(--accent) 22%, transparent); color: var(--accent); }
  .path { color: var(--text); }
  .path .param { color: var(--accent); }
  .desc { color: var(--text-faint); font-family: -apple-system, sans-serif; font-size: 0.82rem; text-align: right; }
  @media (max-width: 640px) {
    .endpoint { grid-template-columns: 60px 1fr; }
    .desc { display: none; }
  }

  /* ---------- stack ---------- */
  .stack-row {
    display: flex;
    flex-wrap: wrap;
    gap: 0.7rem;
  }
  .chip {
    padding: 0.55rem 1rem;
    border: 1px solid var(--line);
    border-radius: 999px;
    font-size: 0.85rem;
    color: var(--text-dim);
    background: var(--surface);
  }

  /* ---------- academic note ---------- */
  .note {
    display: grid;
    grid-template-columns: auto 1fr;
    gap: 1.4rem;
    align-items: start;
    border: 1px solid var(--accent-soft);
    background: var(--accent-ink);
    border-radius: 14px;
    padding: 1.8rem;
  }
  .note .clapper { font-size: 1.6rem; color: var(--accent); line-height: 1; }
  .note h3 { margin: 0 0 0.5rem; font-size: 1.05rem; font-weight: 600; }
  .note p { margin: 0; color: var(--text-dim); font-size: 0.92rem; max-width: 560px; }

  /* ---------- footer ---------- */
  footer {
    border-top: 1px solid var(--line);
    padding: 2.6rem 0;
    color: var(--text-faint);
    font-size: 0.85rem;
  }
  footer .wrap {
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    gap: 1rem;
  }

  @media (prefers-reduced-motion: reduce) {
    .btn, nav.links a { transition: none; }
  }