/* レスポンシブ対応 */
@media (max-width: 768px) {
    .header-container {
        padding: 10px 15px;
    }
    
    .nav {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: white;
        flex-direction: column;
        padding: 20px;
        box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
    }
    
    .nav.active {
        display: flex;
    }
}