:root {
  --bg: #ffffff;
  --text: #1f2328;
  --muted: #59636e;
  --accent: #0b5cad;
  --border: #d1d9e0;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0d1117;
    --text: #e6edf3;
    --muted: #9198a1;
    --accent: #4493f8;
    --border: #30363d;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  line-height: 1.6;
}

header, main, footer {
  max-width: 760px;
  margin: 0 auto;
  padding: 0 16px;
}

header {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  padding-top: 20px;
  padding-bottom: 20px;
  border-bottom: 1px solid var(--border);
}

header .brand {
  font-weight: 700;
  color: var(--text);
  text-decoration: none;
}

nav a {
  margin-left: 16px;
  color: var(--accent);
  text-decoration: none;
}

nav a:first-child { margin-left: 0; }
nav a:hover { text-decoration: underline; }

main { padding-top: 24px; padding-bottom: 40px; }

h1 { margin-top: 0; }
h2 { margin-top: 32px; }

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

.muted { color: var(--muted); }

footer {
  padding-top: 20px;
  padding-bottom: 32px;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.9em;
}