:root {
    --bg: #ffffff;
    --fg: #111111;
    --muted: #6b6b6b;
    --accent: #007AFF;
    --card: #f6f6f7;
    --border: #e5e5ea;
}
@media (prefers-color-scheme: dark) {
    :root {
        --bg: #000000;
        --fg: #f5f5f7;
        --muted: #8e8e93;
        --accent: #0A84FF;
        --card: #1c1c1e;
        --border: #2c2c2e;
    }
}
* { box-sizing: border-box; }
html, body {
    margin: 0;
    padding: 0;
    font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI", Roboto, sans-serif;
    background: var(--bg);
    color: var(--fg);
    line-height: 1.55;
    -webkit-font-smoothing: antialiased;
}
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
.container { max-width: 720px; margin: 0 auto; padding: 32px 20px 80px; }
nav.top { padding: 16px 20px; border-bottom: 1px solid var(--border); display: flex; justify-content: space-between; align-items: center; max-width: 720px; margin: 0 auto; }
nav.top .brand { font-weight: 600; }
nav.top .links a { margin-left: 16px; color: var(--muted); }
h1, h2, h3 { line-height: 1.2; }
h1 { font-size: 2rem; margin: 0 0 8px; }
h2 { font-size: 1.4rem; margin: 32px 0 8px; }
h3 { font-size: 1.1rem; margin: 24px 0 4px; }
p, ul, ol { color: var(--fg); }
.muted { color: var(--muted); }
.card { background: var(--card); border: 1px solid var(--border); border-radius: 14px; padding: 20px; margin: 16px 0; }
.btn {
    display: inline-block; background: var(--accent); color: white;
    padding: 12px 22px; border-radius: 10px; font-weight: 500;
    text-decoration: none;
}
.btn:hover { text-decoration: none; opacity: 0.9; }
footer { color: var(--muted); font-size: 0.85rem; padding: 32px 20px; text-align: center; border-top: 1px solid var(--border); margin-top: 60px; }
footer a { color: var(--muted); margin: 0 8px; }