/* ===== 全局重置与变量 ===== */
:root {
    --primary: #0d47a1;
    --primary-dark: #08306b;
    --primary-light: #1565c0;
    --accent: #e65100;
    --accent-light: #ff6d00;
    --success: #2e7d32;
    --danger: #c62828;
    --warning: #f9a825;
    --text: #212121;
    --text-secondary: #616161;
    --text-light: #9e9e9e;
    --bg: #f5f7fa;
    --bg-dark: #e8eaf6;
    --white: #ffffff;
    --border: #e0e0e0;
    --shadow: 0 2px 12px rgba(0,0,0,0.08);
    --shadow-hover: 0 8px 24px rgba(0,0,0,0.12);
    --radius: 6px;
    --transition: all 0.3s ease;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
    font-family: "Microsoft YaHei", "PingFang SC", "Hiragino Sans GB", sans-serif;
    font-size: 14px;
    line-height: 1.6;
    color: var(--text);
    background: var(--bg);
}

a { text-decoration: none; color: var(--primary); transition: var(--transition); }
a:hover { color: var(--accent); }
img { max-width: 100%; height: auto; display: block; }
ul, ol { list-style: none; }

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 15px;
}

/* ===== 顶部栏 ===== */
.top-bar {
    background: var(--primary-dark);
    color: rgba(255,255,255,0.85);
    font-size: 12px;
    padding: 6px 0;
}
.top-bar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}
.top-bar a {
    color: rgba(255,255,255,0.85);
    margin-left: 20px;
}
.top-bar a:hover { color: var(--white); }

/* ===== 头部 ===== */
.main-header {
    background: var(--white);
    border-bottom: 1px solid var(--border);
    padding: 18px 0;
}
.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 30px;
}
.logo {
    display: flex;
    align-items: center;
    gap: 12px;
    flex-shrink: 0;
}
.logo-icon {
    width: 50px; height: 50px;
    background: var(--primary);
    color: var(--white);
    font-size: 24px;
    font-weight: bold;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius);
}
.logo-title {
    font-size: 20px;
    font-weight: bold;
    color: var(--primary);
    line-height: 1.2;
}
.logo-sub {
    font-size: 12px;
    color: var(--text-secondary);
    margin-top: 2px;
}
.search-box {
    flex: 1;
    max-width: 500px;
}
.search-box form {
    display: flex;
    border: 2px solid var(--primary);
    border-radius: var(--radius);
    overflow: hidden;
}
.search-box input {
    flex: 1;
    border: none;
    padding: 10px 15px;
    font-size: 14px;
    outline: none;
}
.search-box button {
    background: var(--primary);
    color: var(--white);
    border: none;
    padding: 0 24px;
    cursor: pointer;
    font-size: 14px;
    transition: var(--transition);
}
.search-box button:hover { background: var(--primary-dark); }

.header-contact {
    display: flex;
    align-items: center;
    gap: 10px;
    flex-shrink: 0;
}
.phone-icon {
    font-size: 32px;
}
.phone-label {
    font-size: 12px;
    color: var(--text-secondary);
}
.phone-number {
    font-size: 20px;
    font-weight: bold;
    color: var(--accent);
}

/* ===== 导航栏 ===== */
.main-nav {
    background: var(--primary);
    position: relative;
}
.nav-inner {
    display: flex;
    align-items: center;
    height: 48px;
}
.category-dropdown {
    position: relative;
    width: 220px;
}
.cat-trigger {
    background: var(--primary-dark);
    color: var(--white);
    padding: 0 20px;
    height: 48px;
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 15px;
    font-weight: 500;
    cursor: pointer;
}
.cat-icon { font-size: 18px; }
.cat-menu {
    position: absolute;
    top: 48px; left: 0;
    width: 220px;
    background: var(--white);
    box-shadow: var(--shadow-hover);
    z-index: 100;
    display: none;
    border: 1px solid var(--border);
    border-top: none;
}
.category-dropdown:hover .cat-menu { display: block; }
.cat-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 12px 20px;
    color: var(--text);
    border-bottom: 1px solid var(--border);
    transition: var(--transition);
}
.cat-item:hover {
    background: var(--bg);
    color: var(--primary);
    padding-left: 25px;
}
.cat-arrow { color: var(--text-light); font-size: 12px; }

.nav-links {
    display: flex;
    gap: 0;
    margin-left: 10px;
}
.nav-links a {
    color: rgba(255,255,255,0.9);
    padding: 0 24px;
    height: 48px;
    display: flex;
    align-items: center;
    font-size: 15px;
    transition: var(--transition);
}
.nav-links a:hover,
.nav-links a.active {
    background: rgba(255,255,255,0.1);
    color: var(--white);
}

/* ===== 主体内容 ===== */
.main-content { min-height: 500px; }

/* ===== 横幅区域 ===== */
.hero-section {
    background: var(--primary-dark);
    color: var(--white);
    padding: 50px 0;
    margin-bottom: 30px;
}
.hero-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 40px;
}
.hero-text { flex: 1; }
.hero-text h1 {
    font-size: 36px;
    margin-bottom: 15px;
    line-height: 1.3;
}
.hero-text p {
    font-size: 16px;
    color: rgba(255,255,255,0.8);
    margin-bottom: 25px;
    max-width: 500px;
}
.hero-btns {
    display: flex;
    gap: 15px;
}
.btn {
    display: inline-block;
    padding: 12px 30px;
    border-radius: var(--radius);
    font-size: 15px;
    font-weight: 500;
    transition: var(--transition);
    cursor: pointer;
    border: none;
}
.btn-primary {
    background: var(--accent);
    color: var(--white);
}
.btn-primary:hover { background: var(--accent-light); color: var(--white); }
.btn-outline {
    background: transparent;
    color: var(--white);
    border: 2px solid rgba(255,255,255,0.5);
}
.btn-outline:hover {
    background: var(--white);
    color: var(--primary);
    border-color: var(--white);
}
.btn-secondary {
    background: var(--primary);
    color: var(--white);
}
.btn-secondary:hover { background: var(--primary-dark); color: var(--white); }
.btn-danger { background: var(--danger); color: var(--white); }
.btn-sm { padding: 8px 16px; font-size: 13px; }
.btn-lg { padding: 14px 40px; font-size: 16px; }

.hero-image {
    width: 400px;
    flex-shrink: 0;
}
.hero-image img {
    border-radius: var(--radius);
    box-shadow: 0 20px 40px rgba(0,0,0,0.2);
}

/* ===== 服务优势 ===== */
.features-bar {
    background: var(--white);
    padding: 30px 0;
    margin-bottom: 30px;
    border-bottom: 1px solid var(--border);
}
.features-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 20px;
}
.feature-item {
    display: flex;
    align-items: center;
    gap: 15px;
    padding: 15px;
}
.feature-icon {
    width: 50px; height: 50px;
    background: var(--bg-dark);
    color: var(--primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 22px;
    flex-shrink: 0;
}
.feature-text h4 {
    font-size: 15px;
    color: var(--text);
    margin-bottom: 3px;
}
.feature-text p {
    font-size: 12px;
    color: var(--text-secondary);
}

/* ===== 板块标题 ===== */
.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
    padding-bottom: 10px;
    border-bottom: 2px solid var(--border);
}
.section-title {
    font-size: 22px;
    color: var(--text);
    position: relative;
    padding-left: 15px;
}
.section-title::before {
    content: '';
    position: absolute;
    left: 0; top: 4px; bottom: 4px;
    width: 4px;
    background: var(--primary);
    border-radius: 2px;
}
.section-more {
    font-size: 13px;
    color: var(--text-secondary);
}
.section-more:hover { color: var(--primary); }

/* ===== 商品网格 ===== */
.product-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 20px;
}
.product-card {
    background: var(--white);
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: var(--transition);
    position: relative;
}
.product-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-hover);
}
.product-img {
    position: relative;
    padding: 15px;
    height: 200px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg);
}
.product-img img {
    max-height: 170px;
    object-fit: contain;
    transition: var(--transition);
}
.product-card:hover .product-img img { transform: scale(1.05); }
.product-badge {
    position: absolute;
    top: 10px; left: 10px;
    padding: 3px 10px;
    border-radius: 3px;
    font-size: 11px;
    color: var(--white);
    font-weight: 500;
}
.badge-hot { background: var(--danger); }
.badge-new { background: var(--success); }
.product-info { padding: 15px; }
.product-brand {
    font-size: 12px;
    color: var(--primary);
    margin-bottom: 5px;
}
.product-name {
    font-size: 14px;
    color: var(--text);
    line-height: 1.4;
    height: 40px;
    overflow: hidden;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    margin-bottom: 8px;
}
.product-name:hover { color: var(--primary); }
.product-model {
    font-size: 12px;
    color: var(--text-light);
    margin-bottom: 10px;
}
.product-price-row {
    display: flex;
    align-items: baseline;
    gap: 8px;
}
.product-price {
    font-size: 18px;
    font-weight: bold;
    color: var(--accent);
}
.product-original {
    font-size: 13px;
    color: var(--text-light);
    text-decoration: line-through;
}
.product-actions {
    display: flex;
    gap: 8px;
    margin-top: 12px;
}
.product-actions .btn {
    flex: 1;
    text-align: center;
    padding: 8px;
    font-size: 13px;
}

/* ===== 分类展示 ===== */
.category-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 20px;
    margin-bottom: 30px;
}
.category-card {
    background: var(--white);
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: var(--transition);
    display: flex;
    flex-direction: column;
}
.category-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-hover);
}
.category-img {
    height: 140px;
    overflow: hidden;
    background: var(--bg);
    display: flex;
    align-items: center;
    justify-content: center;
}
.category-img img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}
.category-info {
    padding: 15px;
    flex: 1;
    display: flex;
    flex-direction: column;
}
.category-info h3 {
    font-size: 16px;
    margin-bottom: 5px;
    color: var(--text);
}
.category-info p {
    font-size: 12px;
    color: var(--text-secondary);
    line-height: 1.5;
    flex: 1;
}
.category-info .btn {
    margin-top: 10px;
    text-align: center;
}

/* ===== 页脚 ===== */
.main-footer {
    background: var(--primary-dark);
    color: rgba(255,255,255,0.7);
    margin-top: 50px;
}
.footer-top {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 30px;
    padding: 50px 0 30px;
}
.footer-col h4 {
    color: var(--white);
    font-size: 16px;
    margin-bottom: 20px;
    padding-bottom: 10px;
    border-bottom: 1px solid rgba(255,255,255,0.1);
}
.footer-col a {
    display: block;
    color: rgba(255,255,255,0.7);
    padding: 5px 0;
    font-size: 13px;
}
.footer-col a:hover { color: var(--white); }
.footer-col p {
    font-size: 13px;
    line-height: 1.8;
    padding: 3px 0;
}
.footer-contact { margin-top: 15px; }
.footer-contact p { padding: 2px 0; }
.footer-bottom {
    border-top: 1px solid rgba(255,255,255,0.1);
    padding: 20px 0;
    text-align: center;
    font-size: 12px;
}
.footer-bottom a { color: rgba(255,255,255,0.6); }

/* ===== 面包屑 ===== */
.breadcrumb {
    background: var(--white);
    padding: 12px 0;
    border-bottom: 1px solid var(--border);
    font-size: 13px;
    color: var(--text-secondary);
}
.breadcrumb a { color: var(--text-secondary); }
.breadcrumb a:hover { color: var(--primary); }
.breadcrumb .sep { margin: 0 8px; color: var(--text-light); }

/* ===== 页面布局 ===== */
.page-layout {
    display: grid;
    grid-template-columns: 220px 1fr;
    gap: 25px;
    padding: 25px 0;
}
.sidebar {
    background: var(--white);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    overflow: hidden;
    align-self: start;
}
.sidebar-title {
    background: var(--primary);
    color: var(--white);
    padding: 14px 18px;
    font-size: 15px;
    font-weight: 500;
}
.sidebar-menu a {
    display: flex;
    align-items: center;
    padding: 12px 18px;
    color: var(--text);
    border-bottom: 1px solid var(--border);
    font-size: 14px;
    transition: var(--transition);
}
.sidebar-menu a:hover,
.sidebar-menu a.active {
    background: var(--bg);
    color: var(--primary);
    padding-left: 22px;
}
.main-panel {
    background: var(--white);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    padding: 25px;
    min-height: 500px;
}

/* ===== 商品详情 ===== */
.product-detail {
    display: grid;
    grid-template-columns: 400px 1fr;
    gap: 35px;
    padding: 25px;
    background: var(--white);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
}
.detail-gallery {
    background: var(--bg);
    border-radius: var(--radius);
    padding: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 350px;
}
.detail-gallery img {
    max-height: 320px;
    object-fit: contain;
}
.detail-info h1 {
    font-size: 22px;
    color: var(--text);
    margin-bottom: 10px;
    line-height: 1.4;
}
.detail-meta {
    display: flex;
    gap: 20px;
    font-size: 13px;
    color: var(--text-secondary);
    margin-bottom: 15px;
    padding-bottom: 15px;
    border-bottom: 1px solid var(--border);
}
.detail-price-box {
    background: var(--bg);
    padding: 20px;
    border-radius: var(--radius);
    margin-bottom: 20px;
}
.detail-price-row {
    display: flex;
    align-items: baseline;
    gap: 15px;
    margin-bottom: 10px;
}
.detail-price {
    font-size: 28px;
    font-weight: bold;
    color: var(--accent);
}
.detail-original {
    font-size: 16px;
    color: var(--text-light);
    text-decoration: line-through;
}
.detail-saving {
    font-size: 13px;
    color: var(--danger);
}
.detail-attrs {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 10px;
    margin-bottom: 20px;
}
.detail-attr {
    font-size: 13px;
    color: var(--text-secondary);
}
.detail-attr span { color: var(--text); }
.detail-actions {
    display: flex;
    gap: 12px;
}
.detail-actions .btn-lg {
    flex: 1;
    text-align: center;
}

/* 规格表 */
.specs-table {
    width: 100%;
    border-collapse: collapse;
    margin: 15px 0;
}
.specs-table th,
.specs-table td {
    padding: 12px 15px;
    text-align: left;
    border-bottom: 1px solid var(--border);
    font-size: 14px;
}
.specs-table th {
    background: var(--bg);
    color: var(--text-secondary);
    font-weight: normal;
    width: 180px;
}

/* 标签页 */
.tabs-nav {
    display: flex;
    border-bottom: 2px solid var(--border);
    margin-bottom: 20px;
}
.tabs-nav a {
    padding: 12px 25px;
    font-size: 15px;
    color: var(--text-secondary);
    border-bottom: 2px solid transparent;
    margin-bottom: -2px;
}
.tabs-nav a.active,
.tabs-nav a:hover {
    color: var(--primary);
    border-bottom-color: var(--primary);
}
.tab-content { padding: 10px 0; }

/* ===== 购物车 ===== */
.cart-table {
    width: 100%;
    border-collapse: collapse;
}
.cart-table th {
    background: var(--bg);
    padding: 14px;
    text-align: left;
    font-size: 13px;
    color: var(--text-secondary);
    font-weight: 500;
    border-bottom: 2px solid var(--border);
}
.cart-table td {
    padding: 18px 14px;
    border-bottom: 1px solid var(--border);
    vertical-align: middle;
}
.cart-product {
    display: flex;
    align-items: center;
    gap: 15px;
}
.cart-product img {
    width: 70px; height: 70px;
    object-fit: contain;
    border: 1px solid var(--border);
    border-radius: 4px;
    background: var(--bg);
}
.cart-product-info h4 {
    font-size: 14px;
    color: var(--text);
    margin-bottom: 4px;
}
.cart-product-info p {
    font-size: 12px;
    color: var(--text-light);
}
.qty-input {
    display: flex;
    align-items: center;
    border: 1px solid var(--border);
    border-radius: 4px;
    overflow: hidden;
    width: 110px;
}
.qty-input button {
    width: 32px; height: 32px;
    border: none;
    background: var(--bg);
    cursor: pointer;
    font-size: 16px;
    color: var(--text-secondary);
}
.qty-input button:hover { background: var(--border); }
.qty-input input {
    width: 46px;
    border: none;
    text-align: center;
    font-size: 14px;
    outline: none;
}
.cart-price {
    font-size: 16px;
    font-weight: bold;
    color: var(--accent);
}
.cart-remove {
    color: var(--text-light);
    cursor: pointer;
    font-size: 18px;
}
.cart-remove:hover { color: var(--danger); }

.cart-summary {
    background: var(--bg);
    padding: 25px;
    border-radius: var(--radius);
    margin-top: 25px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}
.cart-total {
    font-size: 18px;
}
.cart-total strong {
    font-size: 24px;
    color: var(--accent);
    margin-left: 10px;
}

/* ===== 表单 ===== */
.form-group {
    margin-bottom: 18px;
}
.form-group label {
    display: block;
    font-size: 14px;
    color: var(--text);
    margin-bottom: 6px;
}
.form-group label .required {
    color: var(--danger);
    margin-left: 3px;
}
.form-control {
    width: 100%;
    padding: 10px 14px;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    font-size: 14px;
    transition: var(--transition);
    outline: none;
    font-family: inherit;
}
.form-control:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(13,71,161,0.08);
}
textarea.form-control { resize: vertical; min-height: 100px; }
.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 15px;
}
.form-hint {
    font-size: 12px;
    color: var(--text-light);
    margin-top: 5px;
}
.form-error {
    color: var(--danger);
    font-size: 13px;
    margin-top: 5px;
}

/* ===== 登录注册 ===== */
.auth-box {
    max-width: 420px;
    margin: 40px auto;
    background: var(--white);
    padding: 40px;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
}
.auth-box h2 {
    text-align: center;
    margin-bottom: 25px;
    font-size: 24px;
}
.auth-links {
    text-align: center;
    margin-top: 20px;
    font-size: 13px;
    color: var(--text-secondary);
}

/* ===== 分页 ===== */
.pagination {
    display: flex;
    justify-content: center;
    gap: 6px;
    margin-top: 30px;
}
.page-link,
.page-current,
.page-ellipsis {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 38px;
    height: 38px;
    padding: 0 12px;
    border-radius: var(--radius);
    font-size: 14px;
}
.page-link {
    background: var(--white);
    border: 1px solid var(--border);
    color: var(--text);
}
.page-link:hover {
    background: var(--primary);
    color: var(--white);
    border-color: var(--primary);
}
.page-current {
    background: var(--primary);
    color: var(--white);
    font-weight: 500;
}
.page-ellipsis {
    color: var(--text-light);
}

/* ===== 订单 ===== */
.order-card {
    border: 1px solid var(--border);
    border-radius: var(--radius);
    margin-bottom: 20px;
    overflow: hidden;
}
.order-header {
    background: var(--bg);
    padding: 12px 18px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 13px;
}
.order-header .order-no { font-weight: 500; color: var(--text); }
.order-status {
    padding: 3px 10px;
    border-radius: 3px;
    font-size: 12px;
    font-weight: 500;
}
.status-warning { background: #fff3cd; color: #856404; }
.status-info { background: #d1ecf1; color: #0c5460; }
.status-primary { background: #cce5ff; color: #004085; }
.status-success { background: #d4edda; color: #155724; }
.status-danger { background: #f8d7da; color: #721c24; }
.order-body {
    padding: 18px;
    display: flex;
    gap: 15px;
    align-items: center;
}
.order-body img {
    width: 60px; height: 60px;
    object-fit: contain;
    border: 1px solid var(--border);
    border-radius: 4px;
    background: var(--bg);
}
.order-info { flex: 1; }
.order-info h4 {
    font-size: 14px;
    color: var(--text);
    margin-bottom: 4px;
}
.order-info p {
    font-size: 12px;
    color: var(--text-secondary);
}
.order-total {
    text-align: right;
    padding: 0 18px 18px;
    font-size: 14px;
    border-top: 1px solid var(--border);
    margin-top: -1px;
    padding-top: 12px;
}
.order-total strong {
    color: var(--accent);
    font-size: 18px;
}

/* ===== 关于/联系页面 ===== */
.page-content {
    padding: 30px;
    line-height: 1.8;
    color: var(--text);
}
.page-content h2 {
    font-size: 22px;
    margin: 25px 0 15px;
    color: var(--primary);
    padding-bottom: 10px;
    border-bottom: 2px solid var(--bg-dark);
}
.page-content p {
    margin-bottom: 12px;
    text-align: justify;
}
.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 30px;
}
.contact-info-box {
    background: var(--bg);
    padding: 25px;
    border-radius: var(--radius);
}
.contact-info-box h3 {
    font-size: 18px;
    margin-bottom: 15px;
    color: var(--primary);
}
.contact-info-box p {
    padding: 8px 0;
    font-size: 14px;
    border-bottom: 1px dashed var(--border);
}
.contact-info-box p:last-child { border-bottom: none; }
.contact-info-box strong {
    display: inline-block;
    width: 80px;
    color: var(--text-secondary);
}

/* ===== 响应式 ===== */
@media (max-width: 1024px) {
    .product-grid { grid-template-columns: repeat(3, 1fr); }
    .category-grid { grid-template-columns: repeat(3, 1fr); }
    .page-layout { grid-template-columns: 180px 1fr; }
    .footer-top { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 768px) {
    .header-inner { flex-wrap: wrap; }
    .search-box { order: 3; max-width: 100%; width: 100%; margin-top: 10px; }
    .hero-inner { flex-direction: column; text-align: center; }
    .hero-image { width: 100%; max-width: 300px; }
    .product-grid { grid-template-columns: repeat(2, 1fr); }
    .category-grid { grid-template-columns: repeat(2, 1fr); }
    .features-grid { grid-template-columns: repeat(2, 1fr); }
    .page-layout { grid-template-columns: 1fr; }
    .sidebar { display: none; }
    .product-detail { grid-template-columns: 1fr; }
    .detail-gallery { min-height: 250px; }
    .footer-top { grid-template-columns: 1fr; }
    .nav-links { display: none; }
    .category-dropdown { width: auto; flex: 1; }
    .contact-grid { grid-template-columns: 1fr; }
    .form-row { grid-template-columns: 1fr; }
    .detail-attrs { grid-template-columns: 1fr; }
}

@media (max-width: 480px) {
    .product-grid { grid-template-columns: 1fr; }
    .features-grid { grid-template-columns: 1fr; }
}

/* ===== 提示消息 ===== */
.alert {
    padding: 12px 18px;
    border-radius: var(--radius);
    margin-bottom: 20px;
    font-size: 14px;
}
.alert-success { background: #d4edda; color: #155724; border: 1px solid #c3e6cb; }
.alert-error { background: #f8d7da; color: #721c24; border: 1px solid #f5c6cb; }
.alert-warning { background: #fff3cd; color: #856404; border: 1px solid #ffeaa7; }

/* ===== 空状态 ===== */
.empty-state {
    text-align: center;
    padding: 60px 20px;
    color: var(--text-light);
}
.empty-state-icon {
    font-size: 64px;
    margin-bottom: 15px;
    opacity: 0.5;
}
.empty-state h3 {
    font-size: 18px;
    color: var(--text-secondary);
    margin-bottom: 10px;
}