:root {
  color-scheme: dark;
  --bg: #05070a;
  --panel: rgba(12, 17, 27, .82);
  --line: rgba(255, 255, 255, .09);
  --text: #f5f7fb;
  --muted: #9aa7b8;
  --accent: #7dd3fc;
  --accent-rgb: 125, 211, 252;
  font-family: "Plus Jakarta Sans", Inter, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: var(--bg);
  color: var(--text);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  min-height: 100vh;
  background:
    radial-gradient(circle at 8% 0%, rgba(59, 130, 246, .18), transparent 34rem),
    radial-gradient(circle at 92% 28%, rgba(139, 92, 246, .1), transparent 30rem),
    var(--bg);
  color: var(--text);
  line-height: 1.72;
}

a { color: var(--accent); }
.shell { width: min(980px, calc(100% - 32px)); margin: 0 auto; padding: 28px 0 72px; }
.topbar { display: flex; align-items: center; justify-content: space-between; margin-bottom: 56px; }
.brand { color: var(--text); font-size: 1.1rem; font-weight: 800; letter-spacing: -.05em; text-decoration: none; }
.back { color: var(--muted); font-size: .82rem; text-decoration: none; }
.back:hover { color: #fff; }
.hero { border-bottom: 1px solid var(--line); padding-bottom: 34px; }
.eyebrow { color: var(--accent); font-size: .7rem; font-weight: 800; letter-spacing: .16em; text-transform: uppercase; }
.hero h1 { max-width: 760px; margin: 12px 0 14px; font-size: clamp(2.4rem, 7vw, 4.8rem); line-height: 1; letter-spacing: -.065em; }
.hero p { max-width: 700px; margin: 0 0 14px; color: var(--muted); }
.date { color: #7f8b9b; font-size: .8rem; }
.layout { display: grid; grid-template-columns: 190px minmax(0, 1fr); gap: 52px; padding-top: 44px; }
.toc { position: sticky; top: 24px; align-self: start; color: #78869a; font-size: .76rem; }
.toc strong { display: block; margin-bottom: 12px; color: #dbe2eb; font-size: .68rem; letter-spacing: .12em; text-transform: uppercase; }
.toc a { display: block; margin: 9px 0; color: inherit; text-decoration: none; }
.toc a:hover { color: #fff; }
.content section { margin-bottom: 36px; }
.content h2 { margin: 0 0 10px; color: #fff; font-size: 1.28rem; letter-spacing: -.025em; }
.content p, .content li { color: #a9b4c2; font-size: .95rem; }
.content ul { padding-left: 20px; }
.notice { border: 1px solid rgba(var(--accent-rgb), .24); border-radius: 18px; background: rgba(var(--accent-rgb), .07); padding: 18px 20px; }
.cards { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 14px; margin-top: 18px; }
.card { border: 1px solid var(--line); border-radius: 18px; background: var(--panel); padding: 20px; }
.card strong { display: block; margin-bottom: 6px; color: #fff; }
.card p { margin: 0 0 10px; font-size: .84rem; }
.card a { font-size: .8rem; font-weight: 800; text-decoration: none; }
.footer { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 48px; padding-top: 24px; border-top: 1px solid var(--line); color: #78869a; font-size: .78rem; }
.footer a { color: #aab5c2; }

@media (max-width: 720px) {
  .shell { width: min(100% - 24px, 980px); padding-top: 18px; }
  .topbar { margin-bottom: 38px; }
  .layout { display: block; padding-top: 30px; }
  .toc { position: static; display: flex; gap: 10px; overflow-x: auto; padding-bottom: 26px; white-space: nowrap; }
  .toc strong { display: none; }
  .toc a { margin: 0; border: 1px solid var(--line); border-radius: 999px; padding: 7px 11px; }
  .cards { grid-template-columns: 1fr; }
}

@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }