:root {
  --content-width: 760px;
  --sidebar-width: 320px;
  --gap: 24px;
  --border-color: #ddd;
  --text-color: #222;
  --muted-color: #666;
  --bg-soft: #f8f8f8;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  color: var(--text-color);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.7;
}
a { color: inherit; }
ul { padding-left: 1.2rem; }
img { max-width: 100%; height: auto; }