:root {
  --bg: #ffffff;
  --fg: #1b1f24;
  --muted: #5b6470;
  --accent: #2a53bc;
  --card: #f4f6fb;
  --border: #dde2ec;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0f1216;
    --fg: #e8ebf0;
    --muted: #a3acb9;
    --accent: #7c9cf0;
    --card: #181c22;
    --border: #2a3039;
  }
}
* { box-sizing: border-box; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font: 16px/1.6 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}
header, main, footer { max-width: 760px; margin: 0 auto; padding: 0 16px; }
header { display: flex; align-items: center; gap: 12px; padding-top: 24px; }
header img { width: 40px; height: 40px; border-radius: 10px; }
header a { color: var(--fg); text-decoration: none; font-weight: 700; font-size: 18px; }
nav { margin-left: auto; display: flex; gap: 16px; flex-wrap: wrap; }
nav a { font-weight: 500; font-size: 15px; color: var(--muted); }
main { padding-top: 16px; padding-bottom: 48px; }
h1 { font-size: 30px; line-height: 1.25; margin: 24px 0 8px; }
h2 { font-size: 20px; margin: 32px 0 8px; }
a { color: var(--accent); }
.muted { color: var(--muted); }
.card { background: var(--card); border: 1px solid var(--border); border-radius: 12px; padding: 16px 20px; margin: 16px 0; }
.button { display: inline-block; background: var(--accent); color: #fff; padding: 12px 20px; border-radius: 10px; text-decoration: none; font-weight: 600; }
footer { border-top: 1px solid var(--border); padding-top: 16px; padding-bottom: 32px; color: var(--muted); font-size: 14px; }
ul { padding-left: 20px; }