/* 科技通信网站样式 - 卡云通讯（完整版） */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Microsoft YaHei', 'PingFang SC', sans-serif;
}

:root {
    --primary-color: #0066ff;
    --secondary-color: #0088ff;
    --dark-color: #121828;
    --light-color: #f9fafc;
    --text-color: #333;
    --gray-color: #666;
    --light-gray: #e5e8ef;
    --shadow: 0 2px 12px rgba(0, 102, 255, 0.1);
    --transition: all 0.25s ease;
    --content-max-width: 1200px;
}

body {
    background-color: #f5f7fa;
    color: var(--text-color);
    line-height: 1.7;
    font-size: 15px;
    margin: 0;
    padding: 0;
}

/* 顶部导航 - 修复置顶空白问题 */
header {
    background-color: #fff;
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 1000;
    margin: 0;
    padding: 0;
    width: 100%;
}

.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 12px 5%;
    max-width: var(--content-max-width);
    margin: 0 auto;
    width: 100%;
}

.logo {
    display: flex;
    align-items: center;
}

.logo h1 {
    font-size: 20px;
    color: var(--dark-color);
    font-weight: 600;
    margin-left: 8px;
}

.logo i {
    color: var(--primary-color);
    font-size: 22px;
}

/* 桌面端导航菜单 */
.nav-links {
    display: flex;
    list-style: none;
}

.nav-links li {
    margin-left: 24px;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    transition: var(--transition);
    font-size: 14px;
}

.nav-links a:hover {
    color: var(--primary-color);
}

/* 轮播图 */
.banner {
    position: relative;
    height: 480px;
    overflow: hidden;
    margin: 0 auto;
    max-width: var(--content-max-width);
    border-radius: 0 0 12px 12px;
    margin-top: 0;
}

.slides {
    display: flex;
    width: 400%;
    height: 100%;
    transition: transform 0.6s ease;
}

.slide {
    width: 25%;
    height: 100%;
    position: relative;
}

.slide img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.slide-content {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: flex;
    flex-direction: column;
    justify-content: center;
    padding: 0 8%;
    background: rgba(18, 24, 40, 0.65);
    color: white;
}

.slide-content h2 {
    font-size: 32px;
    margin-bottom: 12px;
    font-weight: 600;
}

.slide-content p {
    font-size: 16px;
    max-width: 500px;
    margin-bottom: 20px;
    opacity: 0.95;
}

.slide-indicators {
    position: absolute;
    bottom: 20px;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
}

.indicator {
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.6);
    margin: 0 6px;
    cursor: pointer;
    transition: var(--transition);
}

.indicator.active {
    background: white;
    transform: scale(1.1);
}

/* 产品列表 */
.products {
    max-width: var(--content-max-width);
    margin: 60px auto;
    padding: 0 5%;
}

.section-title {
    text-align: center;
    margin-bottom: 40px;
}

.section-title h2 {
    font-size: 28px;
    color: var(--dark-color);
    margin-bottom: 16px;
    font-weight: 600;
}

.section-title p {
    color: var(--gray-color);
    max-width: 650px;
    margin: 0 auto;
    font-size: 15px;
    line-height: 1.8;
}

/* Tab页签样式 */
.product-tabs {
    max-width: 850px;
    margin: 0 auto 30px;
    background: white;
    border-radius: 8px;
    padding: 20px;
    box-shadow: var(--shadow);
}

.tabs-header {
    display: flex;
    justify-content: center;
    position: relative;
    margin-bottom: 24px;
    padding-bottom: 8px;
    border-bottom: 1px solid var(--light-gray);
}

.tab-btn {
    background: none;
    border: none;
    padding: 8px 24px;
    font-size: 15px;
    font-weight: 500;
    color: var(--gray-color);
    cursor: pointer;
    transition: var(--transition);
    position: relative;
}

.tab-btn:hover {
    color: var(--primary-color);
}

.tab-btn.active {
    color: var(--primary-color);
    font-weight: 600;
}

.tab-indicator {
    position: absolute;
    bottom: -1px;
    height: 2px;
    background: var(--primary-color);
    border-radius: 2px;
    transition: var(--transition);
}

.tab-content {
    display: none;
    animation: fadeIn 0.3s ease;
}

.tab-content.active {
    display: block;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(8px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* 产品列表项 */
.product-list {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.product-item {
    display: flex;
    background: white;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: var(--transition);
    border: 1px solid #f0f3f9;
}

.product-item:hover {
    transform: translateY(-3px);
    box-shadow: 0 6px 16px rgba(0, 102, 255, 0.12);
}

.product-image {
    flex: 0 0 220px;
    height: 220px;
    overflow: hidden;
}

.product-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: var(--transition);
}

.product-item:hover .product-image img {
    transform: scale(1.03);
}

.product-info {
    flex: 1;
    padding: 20px;
    display: flex;
    flex-direction: column;
}

.product-info h3 {
    font-size: 18px;
    margin-bottom: 8px;
    color: var(--dark-color);
    font-weight: 600;
}

.product-info p {
    color: var(--gray-color);
    margin-bottom: 16px;
    flex-grow: 1;
    font-size: 14px;
}

.product-features {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 16px;
}

.feature {
    background: #f0f7ff;
    color: var(--primary-color);
    padding: 4px 12px;
    border-radius: 16px;
    font-size: 13px;
    font-weight: 500;
}

/* 产品申请按钮 */
.apply-button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    background: var(--primary-color);
    color: white;
    text-decoration: none;
    padding: 8px 20px;
    border-radius: 20px;
    font-weight: 500;
    transition: var(--transition);
    font-size: 14px;
    width: fit-content;
}

.apply-button:hover {
    background: #0058e6;
    color: white;
}

/* 空产品列表样式 */
.no-products-container {
    text-align: center;
    padding: 60px 20px;
    background: white;
    border-radius: 8px;
    box-shadow: var(--shadow);
    margin: 20px auto;
    max-width: 550px;
}

.no-products-icon {
    font-size: 60px;
    color: var(--primary-color);
    margin-bottom: 20px;
    opacity: 0.8;
}

.no-products-title {
    font-size: 22px;
    color: var(--dark-color);
    margin-bottom: 12px;
    font-weight: 600;
}

.no-products-message {
    color: var(--gray-color);
    font-size: 15px;
    line-height: 1.7;
    margin-bottom: 24px;
    max-width: 400px;
    margin-left: auto;
    margin-right: auto;
}

.no-products-button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    background: var(--primary-color);
    color: white;
    text-decoration: none;
    padding: 10px 24px;
    border-radius: 20px;
    font-weight: 500;
    transition: var(--transition);
    font-size: 14px;
}

.no-products-button:hover {
    background: #0058e6;
    color: white;
}

/* 友情链接 */
.friend-links-section {
    max-width: var(--content-max-width);
    margin: 40px auto;
    padding: 0 5%;
}

.friend-links-container {
    background: white;
    border-radius: 8px;
    padding: 20px;
    box-shadow: var(--shadow);
    border: 1px solid #f0f3f9;
}

.friend-links-header {
    text-align: center;
    margin-bottom: 16px;
}

.friend-links-header h2 {
    font-size: 18px;
    color: var(--dark-color);
    margin-bottom: 8px;
    font-weight: 600;
}

.friend-links-subtitle {
    color: var(--gray-color);
    font-size: 13px;
    max-width: 400px;
    margin: 0 auto;
}

.friend-links-grid {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 12px;
}

.friend-link-item {
    display: inline-flex;
    align-items: center;
    padding: 8px 16px;
    background: #f8faff;
    border-radius: 6px;
    transition: var(--transition);
    text-decoration: none;
    color: var(--text-color);
    border: 1px solid #e8f0ff;
    font-size: 13px;
}

.friend-link-item:hover {
    background: #f0f7ff;
    color: var(--primary-color);
}

/* 底部区域 */
footer {
    background: var(--dark-color);
    color: white;
    padding: 40px 5% 20px;
    margin-top: 60px;
}

.footer-content {
    max-width: var(--content-max-width);
    margin: 0 auto;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
    margin-bottom: 30px;
}

.footer-column h3 {
    font-size: 16px;
    margin-bottom: 16px;
    position: relative;
    padding-bottom: 8px;
    font-weight: 600;
}

.footer-column h3::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 30px;
    height: 2px;
    background: var(--primary-color);
}

.footer-column p {
    color: #b0b6c0;
    font-size: 14px;
    line-height: 1.7;
}

.footer-links {
    list-style: none;
}

.footer-links li {
    margin-bottom: 10px;
}

.footer-links a {
    color: #b0b6c0;
    text-decoration: none;
    transition: var(--transition);
    font-size: 14px;
}

.footer-links a:hover {
    color: var(--secondary-color);
    padding-left: 4px;
}

.copyright {
    text-align: center;
    padding-top: 20px;
    border-top: 1px solid rgba(255, 255, 255, 0.08);
    color: #999;
    font-size: 13px;
}

/* 响应式设计 */
@media (max-width: 992px) {
    .product-item {
        flex-direction: column;
    }
    .product-image {
        flex: 0 0 200px;
        width: 100%;
    }
    .banner {
        height: 380px;
    }
}

@media (max-width: 768px) {
    .banner {
        height: 280px;
    }
    .slide-content {
        padding: 0 5%;
    }
    .slide-content h2 {
        font-size: 24px;
    }
    .slide-content p {
        font-size: 14px;
    }
    .section-title h2 {
        font-size: 24px;
    }
    .products {
        margin: 40px auto;
    }
    .product-tabs {
        padding: 16px;
    }
    .tab-btn {
        padding: 6px 16px;
        flex: 1;
        text-align: center;
    }
}

@media (max-width: 576px) {
    .banner {
        height: 220px;
    }
    .slide-content h2 {
        font-size: 20px;
    }
    .section-title {
        margin-bottom: 24px;
    }
    .product-item {
        border-radius: 6px;
    }
    .product-info {
        padding: 16px;
    }
    .no-products-container {
        padding: 40px 16px;
    }
    .footer {
        padding: 30px 5% 16px;
    }
}

@media (max-width: 375px) {
    .logo h1 {
        font-size: 18px;
    }
    .nav-links li {
        margin-left: 16px;
    }
    .banner {
        height: 180px;
    }
    .product-image {
        flex: 0 0 180px;
        height: 180px;
    }
}