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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    min-height: 100vh;
    color: #333;
    line-height: 1.6;
}

/* 导航 */
.navbar {
    background: #2c3e50;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.logo {
    color: #fff;
    font-size: 1.5rem;
    font-weight: bold;
    letter-spacing: 1px;
}

.nav-links {
    list-style: none;
    display: flex;
    gap: 2rem;
}

.nav-links a {
    color: #ecf0f1;
    text-decoration: none;
    transition: color 0.3s;
}

.nav-links a:hover {
    color: #3498db;
}

.hamburger {
    display: none;
    color: #fff;
    font-size: 1.8rem;
    cursor: pointer;
}

/* Hero */
.hero {
    text-align: center;
    padding: 4rem 2rem;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: #fff;
    border-radius: 0 0 30px 30px;
    margin-bottom: 2rem;
}

.hero h1 {
    font-size: 2.2rem;
    margin-bottom: 1rem;
}

.hero p {
    font-size: 1.1rem;
    opacity: 0.9;
}

/* 促销 */
.promotions {
    padding: 2rem;
}

.promo-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin-top: 1rem;
}

.promo-card {
    background: #fff;
    border-radius: 15px;
    padding: 1.5rem;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
    transition: transform 0.3s;
    position: relative;
}

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

.promo-discount {
    position: absolute;
    top: 10px;
    right: 10px;
    background: #e74c3c;
    color: #fff;
    padding: 0.3rem 0.8rem;
    border-radius: 20px;
    font-weight: bold;
}

/* 筛选 */
.filter-section {
    padding: 2rem;
    background: #fff;
    margin: 2rem;
    border-radius: 15px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
}

.filter-form {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    align-items: center;
}

.filter-form input, .filter-form select, .filter-form button {
    padding: 0.7rem 1rem;
    border: 1px solid #ddd;
    border-radius: 8px;
    font-size: 1rem;
}

.filter-form button {
    background: #3498db;
    color: #fff;
    border: none;
    cursor: pointer;
    transition: background 0.3s;
}

.filter-form button:hover {
    background: #2980b9;
}

/* 最佳推荐 */
.best-recommendation {
    padding: 2rem;
}

.best-card {
    background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    color: #fff;
    padding: 2rem;
    border-radius: 15px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.2);
}

.best-card .btn {
    display: inline-block;
    background: #fff;
    color: #333;
    padding: 0.7rem 1.5rem;
    border-radius: 25px;
    text-decoration: none;
    margin-top: 1rem;
    font-weight: bold;
}

/* 产品网格 */
.product-grid {
    padding: 2rem;
}

.grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 1.5rem;
    margin-top: 1rem;
}

.card {
    background: #fff;
    border-radius: 15px;
    padding: 1.5rem;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
    transition: transform 0.3s, box-shadow 0.3s;
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 25px rgba(0,0,0,0.15);
}

.card .brand {
    color: #7f8c8d;
    font-size: 0.9rem;
}

.card .price {
    font-size: 1.5rem;
    color: #e74c3c;
    font-weight: bold;
}

.card .rating {
    color: #f39c12;
}

/* 评价 */
.reviews {
    padding: 2rem;
}

.review-list {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    margin-top: 1rem;
}

.review-item {
    background: #fff;
    padding: 1.5rem;
    border-radius: 10px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

.review-item span {
    font-size: 0.8rem;
    color: #95a5a6;
}

/* 登录表单 */
.login-form {
    max-width: 400px;
    margin: 5rem auto;
    padding: 2rem;
    background: #fff;
    border-radius: 15px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
}

.login-form input {
    width: 100%;
    padding: 0.7rem;
    margin: 0.5rem 0;
    border: 1px solid #ddd;
    border-radius: 8px;
}

.login-form button {
    width: 100%;
    padding: 0.7rem;
    background: #3498db;
    color: #fff;
    border: none;
    border-radius: 8px;
    cursor: pointer;
}

/* 管理后台 */
.admin-panel {
    padding: 2rem;
    max-width: 1200px;
    margin: 0 auto;
}

.admin-item {
    background: #fff;
    padding: 1rem;
    margin: 0.5rem 0;
    border-radius: 10px;
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.admin-item input, .admin-item textarea {
    padding: 0.5rem;
    border: 1px solid #ddd;
    border-radius: 5px;
    flex: 1;
    min-width: 150px;
}

.admin-item textarea {
    height: 60px;
}

.submit-btn {
    background: #2ecc71;
    color: #fff;
    padding: 1rem 2rem;
    border: none;
    border-radius: 8px;
    font-size: 1.1rem;
    cursor: pointer;
    margin-top: 1rem;
}

.error {
    color: #e74c3c;
    background: #fce4e4;
    padding: 0.5rem;
    border-radius: 5px;
    margin: 0.5rem 0;
}

.success {
    color: #27ae60;
    background: #d4edda;
    padding: 0.5rem;
    border-radius: 5px;
    margin: 0.5rem 0;
}

/* 页脚 */
footer {
    background: #2c3e50;
    color: #ecf0f1;
    text-align: center;
    padding: 1.5rem;
    margin-top: 2rem;
}

footer a {
    color: #3498db;
    text-decoration: none;
    margin: 0 0.5rem;
}

/* 响应式 */
@media (max-width: 768px) {
    .hamburger {
        display: block;
    }

    .nav-links {
        display: none;
        flex-direction: column;
        position: absolute;
        top: 60px;
        left: 0;
        width: 100%;
        background: #2c3e50;
        padding: 1rem;
    }

    .nav-links.active {
        display: flex;
    }

    .hero h1 {
        font-size: 1.5rem;
    }

    .filter-form {
        flex-direction: column;
    }

    .filter-form input, .filter-form select, .filter-form button {
        width: 100%;
    }
}