:root {
  color-scheme: dark;
  --bg: #050914;
  --panel: #0c1527;
  --panel-strong: #111e34;
  --text: #f4f8ff;
  --muted: #afbed2;
  --cyan: #54e6ff;
  --line: rgba(133, 221, 255, 0.18);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background:
    radial-gradient(circle at 10% -10%, rgba(32, 163, 207, 0.28), transparent 34rem),
    radial-gradient(circle at 100% 25%, rgba(74, 78, 210, 0.17), transparent 28rem),
    var(--bg);
  color: var(--text);
  font: 16px/1.72 -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", sans-serif;
  min-height: 100vh;
}

a { color: var(--cyan); text-underline-offset: 0.2em; }

.shell { width: min(960px, calc(100% - 32px)); margin: 0 auto; }

header {
  align-items: center;
  display: flex;
  justify-content: space-between;
  padding: 24px 0;
}

.brand { color: var(--text); font-weight: 720; text-decoration: none; }

nav { display: flex; flex-wrap: wrap; gap: 18px; }
nav a { color: var(--muted); font-size: 0.92rem; text-decoration: none; }
nav a:hover, nav a:focus { color: var(--text); }

main { padding: 36px 0 72px; }
.hero { padding: clamp(42px, 9vw, 92px) 0 58px; }
.eyebrow { color: var(--cyan); font-size: 0.82rem; font-weight: 700; letter-spacing: 0.16em; text-transform: uppercase; }
h1 { font-size: clamp(2.45rem, 8vw, 5.4rem); letter-spacing: -0.055em; line-height: 1.05; margin: 14px 0 18px; }
h2 { font-size: clamp(1.45rem, 4vw, 2rem); letter-spacing: -0.025em; margin: 0 0 12px; }
h3 { margin-bottom: 6px; }
.lede { color: var(--muted); font-size: clamp(1.04rem, 2.4vw, 1.25rem); max-width: 690px; }
.meta { color: var(--muted); font-size: 0.92rem; }

.grid { display: grid; gap: 16px; grid-template-columns: repeat(3, 1fr); }
.card, .document section {
  background: linear-gradient(145deg, rgba(18, 32, 56, 0.94), rgba(8, 17, 32, 0.88));
  border: 1px solid var(--line);
  border-radius: 22px;
  padding: 24px;
}
.card { color: var(--text); min-height: 185px; text-decoration: none; }
.card:hover, .card:focus { border-color: rgba(84, 230, 255, 0.52); transform: translateY(-2px); }
.card p, .document p, .document li { color: var(--muted); }
.card .arrow { color: var(--cyan); display: block; margin-top: 18px; }

.document { display: grid; gap: 16px; }
.document section { max-width: 800px; }
.document ul, .document ol { padding-left: 1.3rem; }
.notice { border-left: 3px solid var(--cyan); }

footer { border-top: 1px solid var(--line); color: var(--muted); font-size: 0.86rem; padding: 28px 0 42px; }

@media (max-width: 720px) {
  header { align-items: flex-start; gap: 15px; }
  nav { justify-content: flex-end; gap: 10px 14px; }
  .grid { grid-template-columns: 1fr; }
  main { padding-top: 12px; }
}

@media (prefers-reduced-motion: no-preference) {
  .card { transition: border-color 160ms ease, transform 160ms ease; }
}