:root {
  --bg: #fbfaf7;
  --surface: #ffffff;
  --text: #1d2125;
  --muted: #5b636b;
  --border: #e4e1da;
  --accent: #2f6f6a;
  --accent-soft: #e6f1ef;
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #14171a;
    --surface: #1b1f23;
    --text: #e7e9eb;
    --muted: #a0a8b0;
    --border: #2c3238;
    --accent: #7cc3bb;
    --accent-soft: #1f2e2c;
    color-scheme: dark;
  }
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 17px/1.65 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  -webkit-text-size-adjust: 100%;
}

.wrap {
  max-width: 760px;
  margin: 0 auto;
  padding: 0 16px;
}

header.top {
  border-bottom: 1px solid var(--border);
  background: var(--surface);
}

header.top .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding-top: 14px;
  padding-bottom: 14px;
}

.brand {
  font-weight: 700;
  font-size: 20px;
  letter-spacing: -0.01em;
  color: var(--text);
  text-decoration: none;
}

.brand span { color: var(--muted); font-weight: 400; font-size: 15px; margin-left: 6px; }

nav.links { display: flex; gap: 14px; flex-wrap: wrap; font-size: 15px; }
nav.links a { color: var(--muted); text-decoration: none; }
nav.links a[aria-current="page"] { color: var(--text); font-weight: 600; }
nav.links a:hover { color: var(--accent); }

main { padding: 36px 0 56px; }

h1 { font-size: 34px; line-height: 1.2; margin: 0 0 8px; letter-spacing: -0.02em; }
h2 { font-size: 22px; line-height: 1.3; margin: 40px 0 10px; scroll-margin-top: 16px; }
h3 { font-size: 18px; margin: 24px 0 6px; }

.meta { color: var(--muted); font-size: 15px; margin: 0 0 24px; }

.summary {
  background: var(--accent-soft);
  border-radius: 10px;
  padding: 16px 20px;
  margin: 0 0 28px;
}
.summary p { margin: 0 0 8px; }
.summary ul { margin: 0; padding-left: 20px; }

.toc {
  border: 1px solid var(--border);
  background: var(--surface);
  border-radius: 10px;
  padding: 14px 20px;
  font-size: 15px;
}
.toc ol { margin: 6px 0 0; padding-left: 22px; columns: 2; column-gap: 28px; }
.toc li { break-inside: avoid; }
@media (max-width: 600px) { .toc ol { columns: 1; } }

a { color: var(--accent); }

ul, ol { padding-left: 24px; }
li { margin: 4px 0; }

.table-scroll { overflow-x: auto; margin: 12px 0; }
table { border-collapse: collapse; width: 100%; font-size: 15px; min-width: 520px; }
th, td { text-align: left; vertical-align: top; padding: 10px 12px; border-bottom: 1px solid var(--border); }
th { color: var(--muted); font-weight: 600; }

footer {
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 14px;
  padding: 24px 0 40px;
}
footer p { margin: 4px 0; }