:root {
  --bg: #ffffff;
  --fg: #1d1d1f;
  --muted: #6e6e73;
  --line: #d2d2d7;
  --accent: #0a7c5c;
  --error: #c62828;
  color-scheme: light dark;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #111113;
    --fg: #f2f2f7;
    --muted: #a1a1a6;
    --line: #3a3a3c;
    --accent: #4cc9a0;
    --error: #ff8a80;
  }
}
* { box-sizing: border-box; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font: 16px/1.7 -apple-system, BlinkMacSystemFont, "Hiragino Sans", "PingFang TC", "Noto Sans JP", "Noto Sans TC", system-ui, sans-serif;
}
a { color: var(--accent); }
.top {
  display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 8px;
  max-width: 760px; margin: 0 auto; padding: 16px;
  border-bottom: 1px solid var(--line);
}
.brand { font-weight: 700; color: var(--fg); text-decoration: none; }
.langs ul { display: flex; gap: 14px; list-style: none; margin: 0; padding: 0; font-size: 14px; }
.langs a[aria-current="page"] { color: var(--fg); font-weight: 600; text-decoration: none; }
main { max-width: 760px; margin: 0 auto; padding: 16px 16px 64px; overflow-wrap: anywhere; }
h1 { font-size: 26px; line-height: 1.3; margin: 16px 0 4px; }
h2 { font-size: 19px; margin: 32px 0 8px; }
h3 { font-size: 16px; margin: 20px 0 6px; }
dl { display: grid; grid-template-columns: minmax(8em, max-content) 1fr; gap: 8px 16px; }
dt { font-weight: 600; }
dd { margin: 0; }
@media (max-width: 520px) { dl { grid-template-columns: 1fr; } dd { margin-bottom: 8px; } }
article nav ul, .links { padding-left: 1.2em; }
form { display: grid; gap: 12px; max-width: 360px; }
label { display: grid; gap: 4px; font-weight: 600; }
input { font: inherit; padding: 10px 12px; border: 1px solid var(--line); border-radius: 10px; background: transparent; color: var(--fg); }
button { font: inherit; font-weight: 600; padding: 10px 16px; border: 0; border-radius: 10px; background: var(--accent); color: #fff; cursor: pointer; }
button:disabled { opacity: 0.6; }
.msg { color: var(--error); }
.msg.ok { color: var(--accent); }

/* One language at a time (lang.js sets data-lang before the page is drawn). */
html[data-lang] .l { display: none; }
html[data-lang="ja"] .l:lang(ja),
html[data-lang="en"] .l:lang(en),
html[data-lang="zh-TW"] .l:lang(zh-TW) { display: revert; }
[hidden] { display: none !important; }