:root {
  --bg: #0f172a;
  --bg-alt: #1e293b;
  --border: rgba(51, 65, 85, 0.6);
  --text: #cbd5e1;
  --text-strong: #f8fafc;
  --muted: #94a3b8;
  --accent: #10b981;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: linear-gradient(180deg, #0f172a 0%, #0f172a 55%, #1e293b 100%);
  background-attachment: fixed;
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Inter, Roboto, Helvetica, Arial, sans-serif;
  font-size: 16px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

.wrap { max-width: 820px; margin: 0 auto; padding: 0 20px; }

header.page-header {
  border-bottom: 1px solid var(--border);
  padding: 32px 0 28px;
}

.back {
  color: var(--accent);
  text-decoration: none;
  font-size: 14px;
  font-weight: 500;
}
.back:hover { text-decoration: underline; }

h1 {
  color: var(--text-strong);
  font-size: clamp(28px, 5vw, 40px);
  line-height: 1.2;
  margin: 18px 0 10px;
  letter-spacing: -0.02em;
}

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

main { padding: 40px 0 72px; }

h2 {
  color: var(--text-strong);
  font-size: clamp(20px, 3vw, 24px);
  margin: 44px 0 14px;
  letter-spacing: -0.01em;
}

h3 {
  color: var(--text-strong);
  font-size: 17px;
  margin: 28px 0 10px;
}

p { margin: 0 0 14px; }

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

ul, ol { margin: 0 0 16px; padding-left: 22px; }
li { margin-bottom: 8px; }

strong { color: var(--text-strong); }

.card {
  background: rgba(30, 41, 59, 0.5);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 22px 24px;
  margin: 0 0 20px;
}
.card p:last-child { margin-bottom: 0; }

.callout {
  border-left: 3px solid var(--accent);
  background: rgba(16, 185, 129, 0.07);
  border-radius: 0 10px 10px 0;
  padding: 16px 20px;
  margin: 0 0 20px;
}
.callout p:last-child { margin-bottom: 0; }

.toc { font-size: 15px; }
.toc a { text-decoration: none; }
.toc a:hover { text-decoration: underline; }

.table-wrap { overflow-x: auto; margin: 0 0 20px; }

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 15px;
  min-width: 520px;
}
th, td {
  text-align: left;
  padding: 12px 14px;
  border-bottom: 1px solid var(--border);
  vertical-align: top;
}
th { color: var(--text-strong); font-weight: 600; background: rgba(30, 41, 59, 0.6); }

footer.page-footer {
  border-top: 1px solid var(--border);
  padding: 28px 0 44px;
  color: var(--muted);
  font-size: 14px;
}
footer.page-footer a { margin-right: 16px; }

@media (max-width: 640px) {
  body { font-size: 15px; }
  .card { padding: 18px; }
}