:root {
  --bg: #f5f7fa;
  --panel: #ffffff;
  --text: #1f2937;
  --muted: #6b7280;
  --accent: #0b6ecb;
  --accent-dark: #0a4f8f;
  --border: #e2e8f0;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
}
header {
  background: var(--accent-dark);
  color: #fff;
  padding: 1.2rem 1.5rem;
  position: relative;
}
header h1 { margin: 0; font-size: 1.6rem; }
header .subtitle { color: #cfe3f7; margin: .2rem 0 0; }
.menu-toggle {
  position: absolute;
  top: 1rem;
  right: 1rem;
  background: transparent;
  border: 2px solid rgba(255, 255, 255, .7);
  border-radius: 6px;
  color: #fff;
  font-size: 1.3rem;
  line-height: 1;
  padding: .35rem .6rem;
  cursor: pointer;
}
.menu-toggle:hover { background: rgba(255, 255, 255, .15); }
.menu {
  position: fixed;
  top: 4.5rem;
  right: 1rem;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 8px;
  box-shadow: 0 8px 24px rgba(0, 0, 0, .15);
  min-width: 220px;
  z-index: 100;
}
.menu ul { list-style: none; margin: 0; padding: .4rem 0; }
.menu a {
  display: block;
  padding: .55rem 1.1rem;
  color: var(--text);
  text-decoration: none;
}
.menu a:hover { background: #eef2f7; }
.menu a.active { font-weight: 700; color: var(--accent-dark); }
main {
  max-width: 860px;
  margin: 1.5rem auto;
  padding: 0 1rem 3rem;
}
.card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1.2rem 1.6rem;
  margin-bottom: 1.2rem;
}
h2 { color: var(--accent-dark); }
.subtitle { color: var(--muted); }
code {
  background: #eef2f7;
  padding: .1em .35em;
  border-radius: 4px;
  font-size: .95em;
}
pre {
  background: #eef2f7;
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: .9rem 1.1rem;
  overflow-x: auto;
}
pre code { background: transparent; padding: 0; }
footer {
  text-align: center;
  color: var(--muted);
  font-size: .85rem;
  padding: 1rem;
}