:root {
  --text: #12161c;
  --muted: #5c6672;
  --border: #d8dde5;
  --bg: #ffffff;
}
* { box-sizing: border-box; }
body {
  margin: 0 auto;
  padding: 32px 20px 64px;
  max-width: 720px;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Noto Sans JP", sans-serif;
  line-height: 1.8;
  font-size: 16px;
}
h1 { font-size: 24px; line-height: 1.4; margin: 0 0 4px; }
h2 { font-size: 18px; margin: 40px 0 8px; padding-top: 16px; border-top: 1px solid var(--border); }
h3 { font-size: 15px; margin: 24px 0 4px; }
p, li { color: var(--text); }
ul { padding-left: 20px; }
.meta { color: var(--muted); font-size: 13px; margin: 0 0 24px; }
.lang { color: var(--muted); font-size: 13px; margin-bottom: 32px; }
.lang a { color: inherit; }
nav a { color: var(--muted); font-size: 13px; margin-right: 12px; }
footer { margin-top: 48px; padding-top: 16px; border-top: 1px solid var(--border); color: var(--muted); font-size: 13px; }
code { background: #eef1f5; padding: 1px 5px; border-radius: 4px; font-size: 14px; }
@media (prefers-color-scheme: dark) {
  :root { --text: #e8ebef; --muted: #9aa4b0; --border: #333a44; --bg: #14171c; }
  code { background: #232830; }
}