:root {
  color-scheme: light dark;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", sans-serif;
  --bg: #f7f8fc;
  --card: #ffffff;
  --ink: #171821;
  --soft: #5f6372;
  --line: #e3e6ef;
  --brand: #4d5cdb;
  --brand-soft: #eef0ff;
  --shadow: 0 16px 44px rgba(27, 32, 70, 0.07);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; background: var(--bg); color: var(--ink); line-height: 1.75; }
a { color: var(--brand); text-underline-offset: 3px; }
button, input { font: inherit; }
.shell { width: min(960px, calc(100% - 32px)); margin: 0 auto; }
.topbar { min-height: 76px; display: flex; align-items: center; justify-content: space-between; gap: 20px; }
.brand { display: inline-flex; align-items: center; gap: 11px; color: var(--ink); text-decoration: none; font-weight: 780; }
.mark { display: inline-grid; place-items: center; width: 38px; height: 38px; border-radius: 11px; background: var(--brand); color: #fff; font-size: 21px; font-weight: 850; }
nav { display: flex; flex-wrap: wrap; justify-content: flex-end; gap: 18px; }
nav a { color: var(--soft); text-decoration: none; font-size: 14px; }
nav a[aria-current="page"], nav a:hover { color: var(--brand); }
main { padding: 56px 0 88px; }
.hero { padding: 60px clamp(24px, 6vw, 64px); border: 1px solid var(--line); border-radius: 26px; background: var(--card); box-shadow: var(--shadow); }
.eyebrow { margin: 0 0 12px; color: var(--brand); font-size: 12px; letter-spacing: .12em; font-weight: 800; }
h1 { margin: 0; font-size: clamp(34px, 7vw, 58px); line-height: 1.12; letter-spacing: -.035em; }
.hero > p:not(.eyebrow) { max-width: 660px; margin: 22px 0 0; color: var(--soft); font-size: clamp(16px, 2vw, 19px); }
.actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 30px; }
.button { display: inline-flex; min-height: 46px; align-items: center; justify-content: center; padding: 0 18px; border-radius: 12px; background: var(--brand); color: #fff; text-decoration: none; font-weight: 720; }
.button.secondary { background: var(--brand-soft); color: var(--brand); }
.grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; margin-top: 22px; }
.card { padding: 24px; border: 1px solid var(--line); border-radius: 18px; background: var(--card); }
.card h2 { margin: 0 0 8px; font-size: 19px; }
.card p { margin: 0; color: var(--soft); }
.document { padding: clamp(26px, 6vw, 64px); border: 1px solid var(--line); border-radius: 24px; background: var(--card); box-shadow: var(--shadow); }
.document header { padding-bottom: 28px; border-bottom: 1px solid var(--line); }
.document h1 { font-size: clamp(30px, 5vw, 46px); }
.document .updated { margin: 10px 0 0; color: var(--soft); }
.document section { margin-top: 34px; }
.document h2 { margin: 0 0 12px; font-size: 21px; line-height: 1.35; }
.document p, .document li { color: #343744; }
.document ul, .document ol { padding-left: 22px; }
.notice { padding: 16px 18px; border-radius: 14px; background: var(--brand-soft); color: #303a94; }
.support-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 16px; margin-top: 24px; }
.support-grid article { padding: 22px; border-radius: 16px; background: var(--bg); }
.support-grid h2 { margin-top: 0; font-size: 18px; }
footer { display: flex; justify-content: space-between; gap: 18px; padding: 24px 0 38px; color: var(--soft); font-size: 13px; border-top: 1px solid var(--line); }
footer p { margin: 0; }

@media (prefers-color-scheme: dark) {
  :root { --bg: #0e0f13; --card: #181a21; --ink: #f4f5fa; --soft: #b9bdca; --line: #2d303a; --brand: #9aa7ff; --brand-soft: #242a49; --shadow: none; }
  .mark, .button { color: #101116; }
  .document p, .document li { color: #d7d9e1; }
  .notice { color: #cdd3ff; }
}

@media (max-width: 700px) {
  .topbar { align-items: flex-start; padding: 16px 0; }
  nav { gap: 12px; }
  main { padding-top: 30px; }
  .grid, .support-grid { grid-template-columns: 1fr; }
  footer { flex-direction: column; }
}

@media (max-width: 440px) {
  .topbar { flex-direction: column; }
  nav { justify-content: flex-start; }
  .hero { padding: 36px 22px; border-radius: 20px; }
  .document { padding: 26px 20px; border-radius: 18px; }
}