/* 响应式设计 */
@media (max-width: 768px) {
    .countdown {
        font-size: 4rem;
    }
    
    .container {
        padding: 25px;
    }
    
    h1 {
        font-size: 2rem;
    }
    
    .domain-item {
        padding: 10px;
        font-size: 0.9rem;
        width: 100px;
    }
}

@media (max-width: 480px) {
    .countdown {
        font-size: 3.5rem;
    }
    
    h1 {
        font-size: 1.8rem;
        flex-direction: column;
        gap: 10px;
    }
    
    .action-buttons {
        flex-direction: column;
    }
    
    .btn {
        width: 100%;
        justify-content: center;
    }
    
    .theme-selector {
        position: relative;
        top: 0;
        right: 0;
        justify-content: center;
        margin-bottom: 20px;
    }
}