:root {
    --primary-color: #3b82f6;
    --bg-color: #f8fafc;
    --text-color: #1e293b;
    --card-bg: #ffffff;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 0 20px;
}

header {
    background-color: var(--primary-color);
    color: white;
    padding: 60px 0;
    text-align: center;
}

header h1 {
    font-size: 2.5rem;
    margin-bottom: 10px;
}

main {
    padding: 40px 20px;
}

section {
    margin-bottom: 40px;
}

section h2 {
    font-size: 2rem;
    margin-bottom: 20px;
    border-bottom: 2px solid var(--primary-color);
    display: inline-block;
    padding-bottom: 5px;
}

.grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 20px;
}

.card {
    background-color: var(--card-bg);
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
    transition: transform 0.3s ease;
}

.card:hover {
    transform: translateY(-5px);
}

.card h3 {
    margin-bottom: 10px;
    color: var(--primary-color);
}

footer {
    text-align: center;
    padding: 20px 0;
    margin-top: 40px;
    border-top: 1px solid #e2e8f0;
    color: #64748b;
}

/* 简单的深色模式适配 (可选) */
@media (prefers-color-scheme: dark) {
    :root {
        --primary-color: #60a5fa;
        --bg-color: #0f172a;
        --text-color: #f8fafc;
        --card-bg: #1e293b;
    }
    
    footer {
        border-top: 1px solid #334155;
    }
}