:root {
  --bg: #0a0e17;
  --bg-2: #0f1522;
  --card: #131a2a;
  --border: #222d45;
  --text: #f1f5f9;
  --muted: #a3b0c4;
  --accent: #38bdf8;
  --accent-strong: #0284c7;
  --on-accent: #ffffff;
  --radius: 16px;
  --max: 1040px;
  color-scheme: dark light;
}

@media (prefers-color-scheme: light) {
  :root {
    --bg: #f3f6fb;
    --bg-2: #e9eef6;
    --card: #ffffff;
    --border: #d8e0ec;
    --text: #0f172a;
    --muted: #475569;
    --accent: #0369a1;
    --accent-strong: #0284c7;
  }
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.65 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--accent); text-underline-offset: 3px; }
a:hover { text-decoration-thickness: 2px; }
a:focus-visible, button:focus-visible { outline: 3px solid var(--accent); outline-offset: 3px; border-radius: 6px; }

.skip {
  position: absolute; left: -999px; top: 8px;
  background: var(--accent-strong); color: var(--on-accent);
  padding: 8px 14px; border-radius: 8px; z-index: 10;
}
.skip:focus { left: 8px; }

.wrap { max-width: var(--max); margin: 0 auto; padding: 0 20px; }

header.site {
  position: sticky; top: 0; z-index: 5;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: saturate(160%) blur(12px);
  -webkit-backdrop-filter: saturate(160%) blur(12px);
  border-bottom: 1px solid var(--border);
}
header.site .wrap { display: flex; align-items: center; justify-content: space-between; min-height: 64px; gap: 16px; }
.brand { display: flex; align-items: center; gap: 10px; color: var(--text); text-decoration: none; font-weight: 800; letter-spacing: -0.01em; }
.brand img { width: 32px; height: 32px; border-radius: 8px; }
nav.site { display: flex; gap: 18px; flex-wrap: wrap; }
nav.site a { color: var(--muted); text-decoration: none; font-weight: 600; font-size: 15px; }
nav.site a:hover, nav.site a[aria-current="page"] { color: var(--text); }

.hero { padding: 72px 0 40px; text-align: center; }
.hero .icon { width: 112px; height: 112px; border-radius: 26px; box-shadow: 0 14px 40px rgba(2, 132, 199, 0.35); }
.hero h1 { font-size: clamp(34px, 6vw, 56px); line-height: 1.08; margin: 24px auto 14px; letter-spacing: -0.03em; max-width: 780px; }
.hero p.lead { font-size: clamp(17px, 2.4vw, 21px); color: var(--muted); max-width: 680px; margin: 0 auto 28px; }

.btn {
  display: inline-flex; align-items: center; gap: 8px;
  background: var(--accent-strong); color: var(--on-accent);
  padding: 13px 22px; border-radius: 12px; text-decoration: none; font-weight: 700;
}
.btn:hover { filter: brightness(1.08); }
.btn.ghost { background: transparent; color: var(--text); border: 1px solid var(--border); }
.cta { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; }
.note { color: var(--muted); font-size: 14px; margin-top: 14px; }

section { padding: 44px 0; }
section h2 { font-size: clamp(24px, 4vw, 34px); letter-spacing: -0.02em; margin: 0 0 8px; }
section p.sub { color: var(--muted); margin: 0 0 28px; max-width: 700px; }

.grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(270px, 1fr)); gap: 16px; }
.card { background: var(--card); border: 1px solid var(--border); border-radius: var(--radius); padding: 22px; }
.card h3 { margin: 0 0 6px; font-size: 18px; letter-spacing: -0.01em; }
.card p { margin: 0; color: var(--muted); font-size: 15px; }
.card ul { margin: 8px 0 0; padding-left: 18px; color: var(--muted); font-size: 15px; }

.band { background: var(--bg-2); border-top: 1px solid var(--border); border-bottom: 1px solid var(--border); }

.callout { border-left: 4px solid var(--accent); background: var(--card); padding: 16px 18px; border-radius: 0 12px 12px 0; margin: 22px 0; }
.callout strong { color: var(--text); }

/* long-form pages */
main.doc { padding: 48px 0 24px; }
main.doc h1 { font-size: clamp(30px, 5vw, 44px); letter-spacing: -0.03em; line-height: 1.12; margin: 0 0 8px; }
main.doc .meta { color: var(--muted); margin: 0 0 30px; }
main.doc h2 { font-size: 24px; margin: 40px 0 8px; letter-spacing: -0.02em; }
main.doc h3 { font-size: 18px; margin: 24px 0 4px; }
main.doc p, main.doc li { max-width: 760px; }
main.doc ul { padding-left: 22px; }
main.doc li { margin: 6px 0; }
main.doc table { border-collapse: collapse; width: 100%; max-width: 820px; margin: 14px 0; font-size: 15px; }
main.doc th, main.doc td { text-align: left; border: 1px solid var(--border); padding: 10px 12px; vertical-align: top; }
main.doc th { background: var(--bg-2); }
.toc { background: var(--card); border: 1px solid var(--border); border-radius: 12px; padding: 14px 18px; max-width: 760px; }
.toc ol { margin: 6px 0 0; padding-left: 20px; }

details { background: var(--card); border: 1px solid var(--border); border-radius: 12px; padding: 4px 18px; margin: 10px 0; max-width: 820px; }
summary { cursor: pointer; font-weight: 700; padding: 12px 0; }
details p, details ul { color: var(--muted); margin: 0 0 14px; }

footer.site { border-top: 1px solid var(--border); margin-top: 56px; padding: 30px 0 40px; color: var(--muted); font-size: 14px; }
footer.site .wrap { display: flex; flex-wrap: wrap; gap: 14px 28px; justify-content: space-between; }
footer.site nav { display: flex; gap: 18px; flex-wrap: wrap; }
footer.site a { color: var(--muted); }
footer.site p { margin: 0; max-width: 560px; }

@media (max-width: 560px) {
  header.site .wrap { flex-direction: column; align-items: flex-start; padding-top: 10px; padding-bottom: 10px; }
  .hero { padding-top: 48px; }
}
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }