:root {
  --bg: #F4F6FA;
  --card: #ffffff;
  --ink: #0E1B3D;
  --body: #2b3552;
  --muted: #66708A;
  --line: #E4E8F0;
  --blue: #2F5BEA;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0B1020;
    --card: #141A2C;
    --ink: #F2F5FF;
    --body: #C9D0E4;
    --muted: #8A93AD;
    --line: #232B42;
    --blue: #6E8CFF;
  }
}
* { box-sizing: border-box; }
body {
  font-family: -apple-system, system-ui, "Segoe UI", Roboto, sans-serif;
  color: var(--ink); background: var(--bg);
  margin: 0; padding: 32px 16px; line-height: 1.6;
}
main {
  max-width: 680px; margin: 0 auto; background: var(--card);
  border-radius: 20px; padding: 28px;
}
h1 { margin: 0 0 4px; letter-spacing: -0.5px; font-size: 1.9rem; }
h2 { font-size: 1.05rem; margin: 28px 0 6px; }
p { margin: 0 0 12px; color: var(--body); }
p:last-child { margin-bottom: 0; }
.tag { color: var(--muted); margin: 0 0 8px; }
a { color: var(--blue); }
ol, ul { color: var(--body); padding-left: 22px; }
li { margin-bottom: 8px; }
nav { max-width: 680px; margin: 0 auto 16px; }
nav a { text-decoration: none; font-weight: 600; font-size: 0.95rem; }
footer {
  max-width: 680px; margin: 18px auto 0; color: var(--muted);
  font-size: 0.85rem; text-align: center;
}
footer a { color: var(--muted); }
.links { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 18px; }
.links a {
  display: inline-block; padding: 10px 16px; border: 1px solid var(--line);
  border-radius: 999px; text-decoration: none; font-weight: 600;
}