:root {
  --bg: #fcfcfb;
  --surface: #ffffff;
  --text: #0b0b0b;
  --muted: #52514e;
  --border: #e4e3df;
  --accent: #2a78d6;
  --code-bg: #f0efec;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #1a1a19;
    --surface: #222221;
    --text: #ffffff;
    --muted: #c3c2b7;
    --border: #383835;
    --accent: #3987e5;
    --code-bg: #2c2c2a;
  }
}
:root[data-theme="dark"] {
  --bg: #1a1a19;
  --surface: #222221;
  --text: #ffffff;
  --muted: #c3c2b7;
  --border: #383835;
  --accent: #3987e5;
  --code-bg: #2c2c2a;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.6 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}
main { max-width: 720px; margin: 0 auto; padding: 48px 16px 64px; }
header { margin-bottom: 32px; }
.brand { color: var(--muted); font-size: 14px; letter-spacing: .02em; text-transform: uppercase; }
h1 { font-size: 28px; line-height: 1.25; margin: 4px 0 8px; }
h2 { font-size: 18px; margin: 32px 0 8px; }
p, li { color: var(--text); }
.muted { color: var(--muted); font-size: 14px; }
a { color: var(--accent); }
nav { margin-top: 48px; padding-top: 16px; border-top: 1px solid var(--border); font-size: 14px; }
nav a { margin-right: 16px; }
.card { background: var(--surface); border: 1px solid var(--border); border-radius: 8px; padding: 16px; margin: 16px 0; }
code, .mono {
  font-family: ui-monospace, Consolas, monospace;
  background: var(--code-bg);
  border-radius: 4px;
  padding: 2px 6px;
  word-break: break-all;
}
button {
  font: inherit; color: #fff; background: var(--accent);
  border: 0; border-radius: 6px; padding: 8px 16px; cursor: pointer;
}