:root {
  --bg: #f5f5f7;
  --card: #ffffff;
  --text: #1d1d1f;
  --muted: #6e6e73;
  --accent: #16b87a;
  --rule: rgba(0, 0, 0, 0.08);
  color-scheme: light dark;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #000000;
    --card: #1c1c1e;
    --text: #f5f5f7;
    --muted: #a1a1a6;
    --accent: #42e099;
    --rule: rgba(255, 255, 255, 0.12);
  }
}
* { box-sizing: border-box; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 17px/1.55 -apple-system, BlinkMacSystemFont, "SF Pro Text", "Helvetica Neue", Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
}
main { max-width: 680px; margin: 0 auto; padding: 48px 16px 64px; }
header { display: flex; align-items: center; gap: 16px; margin-bottom: 32px; }
header img { width: 72px; height: 72px; border-radius: 16px; }
header h1 { font-size: 28px; line-height: 1.2; margin: 0; letter-spacing: -0.01em; }
header p { margin: 2px 0 0; color: var(--muted); }
nav { display: flex; gap: 20px; margin-bottom: 28px; }
nav a { color: var(--accent); text-decoration: none; font-weight: 500; }
nav a[aria-current="page"] { color: var(--text); }
section { background: var(--card); border-radius: 18px; padding: 22px 24px; margin-bottom: 16px; }
h2 { font-size: 20px; margin: 0 0 8px; }
h3 { font-size: 17px; margin: 18px 0 4px; }
p, li { margin: 0 0 10px; }
ul { padding-left: 20px; margin: 0; }
a { color: var(--accent); }
.button {
  display: inline-block; margin-top: 6px; padding: 10px 18px; border-radius: 999px;
  background: var(--accent); color: #fff; text-decoration: none; font-weight: 600;
}
footer { color: var(--muted); font-size: 14px; margin-top: 28px; }