:root {
  color-scheme: light dark;
  --ink: #142033;
  --muted: #4c5b70;
  --line: #d5deea;
  --card: #f4f7fb;
  --accent: #0b6bcb;
  --bg: #ffffff;
}

@media (prefers-color-scheme: dark) {
  :root {
    --ink: #e7eef8;
    --muted: #b7c3d4;
    --line: #2c3a4d;
    --card: #152033;
    --accent: #7eb6ff;
    --bg: #0d1520;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: var(--bg);
  color: var(--ink);
  line-height: 1.5;
}

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

header, main, footer {
  width: min(720px, calc(100% - 32px));
  margin: 0 auto;
}

header {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 20px 0 8px;
}

header img {
  width: 48px;
  height: 48px;
  border-radius: 12px;
}

nav {
  display: flex;
  flex-wrap: wrap;
  gap: 12px 16px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--line);
}

nav a { text-decoration: none; }

h1 { font-size: 1.8rem; line-height: 1.2; margin: 24px 0 8px; }

h2 { font-size: 1.15rem; margin: 28px 0 8px; }

p, li { font-size: 1rem; }

.card {
  background: var(--card);
  border-radius: 16px;
  padding: 16px;
  margin: 16px 0;
}

footer {
  padding: 28px 0 40px;
  color: var(--muted);
  font-size: 0.9rem;
}