:root {
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --bg: #f8fafc;
    --card-bg: #ffffff;
    --text: #1e293b;
    --text-light: #64748b;
    --border: #e2e8f0;
    --radius: 8px;
}
* { margin: 0; padding: 0; box-sizing: border-box; }
body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.7;
}
a { color: var(--primary); text-decoration: none; transition: color 0.2s; }
a:hover { color: var(--primary-dark); text-decoration: underline; }
header {
    background: var(--card-bg);
    border-bottom: 1px solid var(--border);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: 0 1px 3px rgba(0,0,0,0.05);
}
header .container { display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: 1rem; }
.logo { font-size: 1.25rem; font-weight: 700; color: var(--text); }
nav { display: flex; flex-wrap: wrap; gap: 0.25rem; }
nav a {
    padding: 0.4rem 0.75rem;
    border-radius: var(--radius);
    font-size: 0.85rem;
    color: var(--text-light);
    transition: background 0.2s, color 0.2s;
}
nav a:hover, nav a.active { background: var(--primary); color: #fff; text-decoration: none; }
.container { max-width: 1100px; margin: 0 auto; padding: 0 1.5rem; }
main { padding: 2rem 0; }
.breadcrumb { font-size: 0.85rem; color: var(--text-light); margin-bottom: 1.5rem; }
.breadcrumb a { color: var(--text-light); }
.breadcrumb span { margin: 0 0.5rem; }
.content-grid { display: grid; grid-template-columns: 1fr 300px; gap: 2rem; align-items: start; }
article {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 2rem;
    border: 1px solid var(--border);
}
article h1 { font-size: 2rem; margin-bottom: 0.5rem; line-height: 1.3; }
.meta { color: var(--text-light); font-size: 0.85rem; margin-bottom: 1.5rem; }
article p { margin-bottom: 1.25rem; }
article h2 { font-size: 1.35rem; margin: 2rem 0 1rem; color: var(--text); }
.sidebar {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 1.5rem;
    border: 1px solid var(--border);
    position: sticky;
    top: 5rem;
}
.sidebar h3 { font-size: 1rem; margin-bottom: 1rem; color: var(--text); }
.sidebar ul { list-style: none; }
.sidebar li { margin-bottom: 0.6rem; }
.sidebar li a { font-size: 0.9rem; display: block; padding: 0.3rem 0; border-bottom: 1px solid var(--border); }
.sidebar li:last-child a { border-bottom: none; }
.card-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); gap: 1.5rem; }
.card {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 1.5rem;
    border: 1px solid var(--border);
    transition: box-shadow 0.2s, transform 0.2s;
}
.card:hover { box-shadow: 0 4px 12px rgba(0,0,0,0.08); transform: translateY(-2px); }
.card h3 { margin-bottom: 0.5rem; }
.card h3 a { color: var(--text); }
.card p { font-size: 0.9rem; color: var(--text-light); }
.hero {
    background: linear-gradient(135deg, #2563eb 0%, #7c3aed 100%);
    color: #fff;
    padding: 4rem 0;
    margin-bottom: 2rem;
    text-align: center;
}
.hero h1 { font-size: 2.5rem; margin-bottom: 0.75rem; }
.hero p { font-size: 1.1rem; opacity: 0.9; max-width: 600px; margin: 0 auto; }
footer {
    background: var(--card-bg);
    border-top: 1px solid var(--border);
    padding: 2rem 0;
    margin-top: 3rem;
    text-align: center;
    color: var(--text-light);
    font-size: 0.85rem;
}
@media (max-width: 768px) {
    .content-grid { grid-template-columns: 1fr; }
    .sidebar { position: static; }
    .hero h1 { font-size: 1.75rem; }
    nav { gap: 0.15rem; }
    nav a { padding: 0.3rem 0.5rem; font-size: 0.75rem; }
}