:root {
    --bg: #fafafa;
    --fg: #1a1a1a;
    --muted: #555;
    --accent: #2563eb;
    --border: #e5e7eb;
}

@media (prefers-color-scheme: dark) {
    :root {
        --bg: #0f172a;
        --fg: #e2e8f0;
        --muted: #94a3b8;
        --accent: #60a5fa;
        --border: #1e293b;
    }
}

* { box-sizing: border-box; }

body {
    margin: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
                 "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    background: var(--bg);
    color: var(--fg);
    line-height: 1.65;
    font-size: 16px;
}

.container {
    max-width: 720px;
    margin: 0 auto;
    padding: 3rem 1.5rem;
}

header {
    border-bottom: 1px solid var(--border);
    padding-bottom: 1rem;
    margin-bottom: 2rem;
    display: flex;
    align-items: baseline;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 1rem;
}

header h1 {
    margin: 0;
    font-size: 1.5rem;
}

header h1 a {
    color: inherit;
    text-decoration: none;
}

nav a {
    color: var(--muted);
    text-decoration: none;
    margin-left: 1rem;
    font-size: 0.95rem;
}

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

article h2 {
    margin-top: 2.5rem;
    font-size: 1.2rem;
}

article p, article li {
    color: var(--fg);
}

article ul {
    padding-left: 1.25rem;
}

footer {
    margin-top: 3rem;
    padding-top: 1rem;
    border-top: 1px solid var(--border);
    color: var(--muted);
    font-size: 0.875rem;
}

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