body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    line-height: 1.6;
    margin: 0;
    padding: 0;
    background-color: #f4f6f8;
    color: #333;
}
.container {
    max-width: 900px;
    margin: 40px auto;
    padding: 0 20px;
}
header {
    text-align: center;
    margin-bottom: 40px;
}
header h1 {
    color: #1a73e8;
    margin-bottom: 10px;
}
.grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 20px;
}
.set-card {
    background: #fff;
    border-radius: 8px;
    padding: 20px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
    transition: transform 0.2s;
}
.set-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0,0,0,0.1);
}
.btn {
    display: inline-block;
    background: #1a73e8;
    color: white;
    padding: 8px 16px;
    border-radius: 4px;
    text-decoration: none;
    margin-top: 10px;
    margin-right: 5px;
    font-size: 14px;
}
.btn.secondary {
    background: #5f6368;
}
.btn:hover {
    opacity: 0.9;
}
footer {
    text-align: center;
    margin-top: 60px;
    color: #666;
    font-size: 14px;
}