:root {
  color-scheme: light dark;
  --background: #f6f7fb;
  --surface: rgba(255, 255, 255, 0.86);
  --text: #16181d;
  --muted: #626873;
  --line: rgba(22, 24, 29, 0.1);
  --accent: #4f46e5;
}

@media (prefers-color-scheme: dark) {
  :root {
    --background: #101116;
    --surface: rgba(28, 30, 38, 0.9);
    --text: #f4f5f7;
    --muted: #a9afba;
    --line: rgba(255, 255, 255, 0.11);
    --accent: #a5b4fc;
  }
}

* { box-sizing: border-box; }

html {
  background: var(--background);
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "PingFang SC", "Segoe UI", sans-serif;
  color: var(--text);
  -webkit-font-smoothing: antialiased;
}

body { margin: 0; }

main {
  width: min(100% - 32px, 760px);
  margin: 56px auto;
  padding: clamp(28px, 6vw, 56px);
  border: 1px solid var(--line);
  border-radius: 28px;
  background: var(--surface);
  box-shadow: 0 22px 70px rgba(15, 23, 42, 0.08);
  backdrop-filter: blur(18px);
}

.eyebrow {
  margin: 0 0 12px;
  color: var(--accent);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

h1 {
  margin: 0 0 12px;
  font-size: clamp(34px, 7vw, 54px);
  line-height: 1.08;
  letter-spacing: -0.045em;
}

h2 {
  margin: 38px 0 10px;
  font-size: 21px;
  letter-spacing: -0.02em;
}

h3 {
  margin: 26px 0 8px;
  font-size: 17px;
}

p, li {
  color: var(--muted);
  font-size: 16px;
  line-height: 1.78;
}

.updated { margin-bottom: 34px; font-size: 14px; }

a { color: var(--accent); text-underline-offset: 3px; }
a:focus-visible { outline: 3px solid var(--accent); outline-offset: 4px; border-radius: 4px; }

.back {
  display: inline-block;
  margin-top: 40px;
  font-weight: 600;
  text-decoration: none;
}

footer {
  width: min(100% - 32px, 760px);
  margin: -28px auto 48px;
  color: var(--muted);
  font-size: 13px;
  text-align: center;
}

@media (max-width: 520px) {
  main { margin: 16px auto 44px; border-radius: 20px; }
  footer { margin-top: -28px; }
}