:root {
  --ink: #164e63;
  --deep: #0f3c4b;
  --cyan: #0891b2;
  --aqua: #ecfeff;
  --line: rgba(8, 145, 178, .18);
}
* { box-sizing: border-box; }
body {
  margin: 0;
  color: var(--ink);
  background: linear-gradient(180deg, var(--aqua), #fff 420px);
  font: 17px/1.7 system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}
a { color: var(--cyan); text-underline-offset: 3px; }
header { border-bottom: 1px solid var(--line); background: rgba(255,255,255,.9); }
.nav, main, footer { width: min(780px, calc(100% - 36px)); margin: 0 auto; }
.nav { min-height: 72px; display: flex; align-items: center; justify-content: space-between; gap: 20px; }
.brand { color: var(--deep); font-size: 21px; font-weight: 800; text-decoration: none; }
.back { font-size: 14px; font-weight: 700; }
main { padding: 72px 0 84px; }
h1, h2 { color: var(--deep); line-height: 1.15; letter-spacing: -.025em; }
h1 { margin: 0 0 10px; font-size: clamp(40px, 8vw, 62px); }
h2 { margin: 38px 0 8px; font-size: 23px; }
p, li { color: #496873; }
.updated { margin-bottom: 42px; color: var(--cyan); font-size: 14px; font-weight: 700; }
.note { margin-top: 40px; padding: 20px; border: 1px solid var(--line); border-radius: 16px; background: #fff; }
footer { padding: 26px 0 44px; border-top: 1px solid var(--line); color: #607983; font-size: 13px; }