:root {
  --bg: #f6f7f9;
  --surface: #ffffff;
  --text: #1d2129;
  --text-2: #4e5969;
  --text-3: #86909c;
  --line: #e5e6eb;
  --accent: #1f6feb;
  --accent-soft: #eef4ff;
  --radius: 12px;
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #111317;
    --surface: #1a1d23;
    --text: #e8eaed;
    --text-2: #b4b9c2;
    --text-3: #868c96;
    --line: #2c3038;
    --accent: #6ea8ff;
    --accent-soft: #1b2638;
    color-scheme: dark;
  }
}

:root[data-theme="dark"] {
  --bg: #111317;
  --surface: #1a1d23;
  --text: #e8eaed;
  --text-2: #b4b9c2;
  --text-3: #868c96;
  --line: #2c3038;
  --accent: #6ea8ff;
  --accent-soft: #1b2638;
  color-scheme: dark;
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.75 -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB",
        "Microsoft YaHei", "Noto Sans CJK SC", "Segoe UI", Roboto, sans-serif;
  word-break: break-word;
}

.page {
  max-width: 760px;
  margin: 0 auto;
  padding: 32px 16px 64px;
}

header.doc-head { margin-bottom: 24px; }

.brand {
  font-size: 14px;
  color: var(--text-3);
  letter-spacing: .02em;
  margin: 0 0 8px;
}

h1 {
  font-size: 28px;
  line-height: 1.3;
  margin: 0 0 12px;
}

.meta {
  font-size: 14px;
  color: var(--text-2);
  margin: 0;
}

.meta span { display: inline-block; white-space: nowrap; margin-right: 16px; }

.card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 20px;
  margin: 20px 0;
}

.card.summary { background: var(--accent-soft); border-color: transparent; }

.card h2 { margin-top: 0; }

h2 {
  font-size: 20px;
  line-height: 1.4;
  margin: 40px 0 12px;
  padding-top: 8px;
  scroll-margin-top: 16px;
}

h3 {
  font-size: 17px;
  margin: 24px 0 8px;
  scroll-margin-top: 16px;
}

p { margin: 0 0 12px; }

ul, ol { padding-left: 1.4em; margin: 0 0 12px; }

li { margin: 4px 0; }

strong { font-weight: 600; }

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
a:active { opacity: .7; }

.toc ol { margin: 0; padding-left: 1.4em; columns: 2; column-gap: 24px; }
.toc li { break-inside: avoid; }

.table-wrap { overflow-x: auto; margin: 0 0 16px; }

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 15px;
  background: var(--surface);
}

th, td {
  border: 1px solid var(--line);
  padding: 8px 10px;
  text-align: left;
  vertical-align: top;
}

th { background: var(--bg); font-weight: 600; white-space: nowrap; }

.muted { color: var(--text-2); font-size: 15px; }

footer.doc-foot {
  margin-top: 48px;
  padding-top: 16px;
  border-top: 1px solid var(--line);
  font-size: 14px;
  color: var(--text-3);
}

.links { list-style: none; padding: 0; margin: 0; }
.links li { margin: 0; }
.links a {
  display: block;
  padding: 14px 16px;
  border-top: 1px solid var(--line);
  color: var(--text);
}
.links li:first-child a { border-top: 0; }
.links a span { display: block; font-size: 14px; color: var(--text-3); }
.links a:hover { text-decoration: none; background: var(--bg); }

.card.flush { padding: 0; overflow: hidden; }

@media (max-width: 560px) {
  h1 { font-size: 24px; }
  .toc ol { columns: 1; }
  .card { padding: 16px; }
  th, td { padding: 6px 8px; font-size: 14px; }
}

@media print {
  body { background: #fff; color: #000; }
  .card { border: 1px solid #ccc; background: #fff; }
  a { color: #000; }
}