:root {
  --bg: #ffffff;
  --text: #16181a;
  --muted: #5b6168;
  --line: #e4e7ea;
  --card: #f5f7f8;
  --accent: #0d8f7c;
  color-scheme: light dark;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0b0d0e;
    --text: #f2f4f5;
    --muted: #a1a7ad;
    --line: #23282c;
    --card: #15191b;
    --accent: #3dd9c1;
  }
}
* { box-sizing: border-box; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 17px/1.6 -apple-system, BlinkMacSystemFont, "SF Pro Text", "Helvetica Neue", Helvetica, Arial, sans-serif;
  -webkit-text-size-adjust: 100%;
}
main { max-width: 680px; margin: 0 auto; padding: 56px 20px 72px; }
header { display: flex; align-items: center; gap: 16px; margin-bottom: 32px; }
header img { width: 72px; height: 72px; border-radius: 50%; }
h1 { font-size: 32px; line-height: 1.2; margin: 0; letter-spacing: -0.01em; }
.tagline { margin: 4px 0 0; color: var(--muted); }
h2 { font-size: 21px; margin: 40px 0 8px; }
h3 { font-size: 17px; margin: 24px 0 4px; }
p, li { color: var(--text); }
.muted { color: var(--muted); }
a { color: var(--accent); }
ul { padding-left: 22px; }
.card { background: var(--card); border: 1px solid var(--line); border-radius: 14px; padding: 18px 20px; margin: 24px 0; }
.card p { margin: 0; }
nav { display: flex; gap: 20px; margin-top: 48px; padding-top: 20px; border-top: 1px solid var(--line); font-size: 15px; }
footer { margin-top: 16px; font-size: 14px; color: var(--muted); }