:root {
  color-scheme: light dark;
  --bg: #ffffff;
  --fg: #111111;
  --muted: #6b6b6f;
  --line: rgba(0, 0, 0, .08);
  --card: rgba(0, 0, 0, .035);
  --link: #0a84ff;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0b0b0c;
    --fg: #f5f5f7;
    --muted: #a1a1a6;
    --line: rgba(255, 255, 255, .10);
    --card: rgba(255, 255, 255, .05);
    --link: #64a8ff;
  }
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "SF Pro Display",
               "Helvetica Neue", Arial, "PingFang TC", "PingFang SC",
               "Hiragino Sans", "Yu Gothic", "Apple SD Gothic Neo", sans-serif;
  line-height: 1.72;
}
main {
  width: min(820px, calc(100% - 40px));
  margin: 0 auto;
  padding: 64px 0 96px;
}
header { margin-bottom: 42px; }
h1 {
  margin: 0 0 10px;
  font-size: clamp(34px, 6vw, 52px);
  line-height: 1.08;
  letter-spacing: -0.03em;
}
.updated { color: var(--muted); font-size: 14px; margin-top: 8px; }
h2 {
  margin: 38px 0 12px;
  padding-top: 8px;
  font-size: 22px;
  line-height: 1.3;
  letter-spacing: -0.015em;
}
h3 { margin: 24px 0 8px; font-size: 18px; line-height: 1.4; }
p { margin: 10px 0; }
ul { margin: 10px 0; padding-left: 24px; }
li { margin: 4px 0; }
strong { font-weight: 650; }
a { color: var(--link); text-decoration: none; }
a:hover { text-decoration: underline; }
.lang {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 14px;
  margin-top: 20px;
  font-size: 14px;
}
footer {
  margin-top: 56px;
  padding-top: 24px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 14px;
}

@media (max-width: 640px) {
  main { width: min(100% - 28px, 820px); padding: 40px 0 72px; }
  h2 { margin-top: 32px; }
}