* {
    margin: 0;
    padding: 0;
}

body {
    font-family: "Microsoft YaHei", Arial, sans-serif;
    background-color: #f5f5f5;
    color: #333;
}

.header {
    background: linear-gradient(135deg, #1a4d6e 0%, #2c7a9b 100%);
    padding: 20px;
    color: white;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.header .logo h1 {
    font-size: 28px;
    font-weight: bold;
}

.header .lang-switch {
    display: flex;
    gap: 10px;
}

.header .lang-switch a {
    color: white;
    text-decoration: none;
    padding: 5px 10px;
    border-radius: 3px;
    transition: background-color 0.3s;
}

.header .lang-switch a.active {
    background-color: rgba(255, 255, 255, 0.3);
}

.header .lang-switch a:hover {
    background-color: rgba(255, 255, 255, 0.2);
}

.nav {
    background-color: #2c3e50;
    padding: 0;
}

.nav ul {
    list-style: none;
    display: flex;
    justify-content: center;
    margin: 0;
    padding: 0;
}

.nav ul li {
    margin: 0;
}

.nav ul li a {
    display: block;
    padding: 15px 25px;
    color: white;
    text-decoration: none;
    transition: background-color 0.3s;
}

.nav ul li a:hover,
.nav ul li a.current,
.nav ul li a.nav-link:hover {
    background-color: #34495e;
}

.main-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

.banner {
    position: relative;
    width: 100%;
    max-width: 1500px;
    height: 600px;
    overflow: hidden;
    margin: 0 auto 30px;
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.banner-slides {
    position: relative;
    width: 100%;
    height: 100%;
}

.banner-slides .slide {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    opacity: 0;
    transition: opacity 0.5s ease-in-out;
}

.banner-slides .slide.active {
    opacity: 1;
}

.banner-slides .slide img {
    width: 100%;
    height: 100%;
    display: block;
    object-fit: cover;
}

.banner-text {
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    background-color: rgba(42, 122, 155, 0.5);
    color: white;
    padding: 30px 60px;
    text-align: center;
    width: 80%;
    max-width: 800px;
}

.banner-text h3 {
    font-size: 24px;
    margin: 0 0 15px 0;
    font-weight: bold;
}

.banner-text p {
    font-size: 16px;
    margin: 0;
    line-height: 1.6;
}

.banner-controls {
    position: absolute;
    bottom: 20px;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    gap: 10px;
    z-index: 10;
}

.banner-controls .control {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background-color: rgba(255, 255, 255, 0.5);
    cursor: pointer;
    transition: background-color 0.3s;
}

.banner-controls .control.active {
    background-color: #2c7a9b;
}

.banner-arrows {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    width: 100%;
    display: flex;
    justify-content: space-between;
    padding: 0 20px;
    box-sizing: border-box;
    z-index: 10;
}

.banner-arrow {
    width: 50px;
    height: 50px;
    background-color: rgba(0, 0, 0, 0.5);
    color: white;
    font-size: 30px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    border-radius: 50%;
    transition: background-color 0.3s;
    user-select: none;
}

.banner-arrow:hover {
    background-color: rgba(0, 0, 0, 0.8);
}

.content-section {
    margin-bottom: 40px;
    background-color: white;
    padding: 30px;
    border-radius: 8px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.content-section h2 {
    color: #1a4d6e;
    margin-bottom: 20px;
    padding-bottom: 10px;
    border-bottom: 2px solid #2c7a9b;
}

.products-intro,
.projects-intro {
    color: #666;
    font-size: 14px;
    margin-bottom: 20px;
    font-style: italic;
}

.about-content {
    display: flex;
    gap: 40px;
    align-items: stretch;
}

.about-text {
    flex: 1;
    min-width: 0;
}

.about-text p {
    line-height: 1.8;
    margin-bottom: 15px;
    text-align: justify;
}

.about-image {
    flex: 1;
    min-width: 0;
}

.about-image img {
    width: 100%;
    height: auto;
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
    display: block;
}

.products-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
    max-width: 1000px;
    margin: 0 auto;
}

.product-item {
    text-align: center;
    margin: 0;
}

.product-item a {
    display: block;
    text-decoration: none;
    color: #333;
    transition: transform 0.3s;
}

.product-item a:hover {
    transform: translateY(-5px);
}

.product-item img {
    width: 100%;
    height: auto;
    max-height: 250px;
    object-fit: contain;
    border-radius: 8px;
    margin-bottom: 10px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.product-item p {
    font-weight: bold;
    color: #2c7a9b;
    margin-top: 10px;
}

.projects-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 20px;
    max-width: 1000px;
    margin: 0 auto;
}

.project-item {
    text-align: center;
}

.project-item a {
    display: block;
    text-decoration: none;
    color: #333;
    transition: transform 0.3s;
}

.project-item a:hover {
    transform: translateY(-5px);
}

.project-item img, .project-video video {
    width: 100%;
    height: auto;
    max-height: 250px;
    object-fit: contain;
    border-radius: 8px;
    margin-bottom: 10px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.project-item p {
    font-weight: bold;
    color: #2c7a9b;
}

.products-page,
.projects-page,
.project-page,
.contact-page {
    display: flex;
    gap: 30px;
}

.products-main,
.product-main,
.project-content {
    flex: 1;
}

.product-page {
    display: flex;
    gap: 30px;
}

.product-sidebar {
    flex: 0 0 200px;
}

.product-main {
    flex: 1;
}

.product-main h2 {
    color: #1a4d6e;
    margin-bottom: 20px;
    padding-bottom: 10px;
    border-bottom: 2px solid #2c7a9b;
}

.product-content {
    display: flex;
    gap: 30px;
    margin-bottom: 30px;
}

.product-image {
    flex: 0 0 400px;
}

.product-image img {
    width: 100%;
    height: auto;
    border-radius: 8px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.product-description {
    flex: 1;
    line-height: 1.8;
    color: #666;
}

.product-parameters {
    background-color: #f8f9fa;
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.product-parameters h3 {
    color: #1a4d6e;
    margin-bottom: 15px;
    padding-bottom: 10px;
    border-bottom: 2px solid #2c7a9b;
}

.parameter-table {
    width: 100%;
    border-collapse: collapse;
}

.parameter-table th,
.parameter-table td {
    padding: 12px;
    text-align: left;
    border-bottom: 1px solid #ddd;
}

.parameter-table th {
    background-color: #2c7a9b;
    color: white;
    font-weight: bold;
}

.parameter-table td {
    color: #666;
}

.parameter-table tr:last-child td {
    border-bottom: none;
}

.products-sidebar h2,
.product-sidebar h2 {
    color: #1a4d6e;
    margin-bottom: 15px;
    padding-bottom: 10px;
    border-bottom: 2px solid #2c7a9b;
}

.products-sidebar ul,
.product-sidebar ul {
    list-style: none;
    padding: 0;
}

.products-sidebar ul li,
.product-sidebar ul li {
    margin-bottom: 10px;
}

.products-sidebar ul li a,
.product-sidebar ul li a {
    display: block;
    padding: 8px 15px;
    color: #666;
    text-decoration: none;
    border-radius: 4px;
    transition: all 0.3s;
}

.products-sidebar ul li a:hover,
.products-sidebar ul li a.active,
.product-sidebar ul li a:hover,
.products-sidebar ul li a.active {
    background-color: #2c7a9b;
    color: white;
}

.product-sidebar ul li ul {
    list-style: none;
    padding-left: 20px;
    margin-top: 5px;
}

.product-sidebar ul li ul li {
    margin-bottom: 5px;
}

.product-sidebar ul li ul li a {
    display: block;
    padding: 6px 12px;
    color: #888;
    text-decoration: none;
    font-size: 14px;
    border-radius: 4px;
    transition: all 0.3s;
}

.product-sidebar ul li ul li a:hover,
.product-sidebar ul li ul li a.active {
    background-color: #3a8cb5;
    color: white;
}

.product-sidebar .category-item {
    margin-bottom: 5px;
}

.product-sidebar .category-item .category-toggle {
    display: block;
    padding: 10px 15px;
    color: #1a4d6e;
    text-decoration: none;
    font-weight: bold;
    background-color: #e8f4f8;
    border-radius: 4px;
    cursor: pointer;
    transition: all 0.3s;
    position: relative;
}

.product-sidebar .category-item .category-toggle:hover {
    background-color: #2c7a9b;
    color: white;
}

.product-sidebar .category-item .category-toggle::after {
    content: '▼';
    position: absolute;
    right: 15px;
    top: 50%;
    transform: translateY(-50%);
    transition: transform 0.3s;
}

.product-sidebar .category-item.active .category-toggle,
.product-sidebar .category-item .category-toggle.open {
    background-color: #2c7a9b;
    color: white;
}

.product-sidebar .category-item.active .category-toggle::after,
.product-sidebar .category-item .category-toggle.open::after {
    transform: translateY(-50%) rotate(180deg);
}

.product-sidebar .product-list {
    list-style: none;
    padding: 0;
    margin: 0;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s ease-in-out;
}

.product-sidebar .product-list.open {
    max-height: 500px;
    transition: max-height 0.4s ease-in-out;
}

.product-sidebar .product-list li {
    margin-bottom: 0;
}

.product-sidebar .product-list li a {
    display: block;
    padding: 8px 20px;
    color: #666;
    text-decoration: none;
    font-size: 14px;
    border-left: 3px solid transparent;
    transition: all 0.3s;
}

.product-sidebar .product-list li a:hover {
    background-color: #f0f8fc;
    border-left-color: #2c7a9b;
    color: #1a4d6e;
}

.product-sidebar .product-list li a.active {
    background-color: #2c7a9b;
    color: white;
    border-left-color: #1a4d6e;
}

.contact-info {
    display: flex;
    gap: 30px;
}

.contact-left,
.contact-right {
    flex: 1;
}

.contact-left p {
    margin-bottom: 15px;
    line-height: 1.6;
}

.contact-left strong {
    color: #1a4d6e;
}

.contact-right form {
    background-color: #f9f9f9;
    padding: 20px;
    border-radius: 8px;
}

.form-group {
    margin-bottom: 15px;
}

.form-group label {
    display: block;
    margin-bottom: 5px;
    color: #666;
    font-weight: bold;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 10px;
    border: 1px solid #ddd;
    border-radius: 4px;
    font-size: 14px;
    box-sizing: border-box;
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: #2c7a9b;
}

.form-group button {
    background-color: #2c7a9b;
    color: white;
    padding: 10px 30px;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 16px;
    transition: background-color 0.3s;
}

.form-group button:hover {
    background-color: #1a4d6e;
}

.success-message {
    background-color: #d4edda;
    color: #155724;
    padding: 10px;
    border-radius: 4px;
    margin-bottom: 15px;
}

.error-message {
    background-color: #f8d7da;
    color: #721c24;
    padding: 10px;
    border-radius: 4px;
    margin-bottom: 15px;
}

.footer {
    background-color: #1a4d6e;
    color: white;
    padding: 40px 20px 20px;
    margin-top: 40px;
}

.footer-content {
    display: flex;
    justify-content: space-around;
    max-width: 1200px;
    margin: 0 auto;
}

.footer-section {
    flex: 1;
    margin: 0 10px;
}

.footer-section h3 {
    margin-bottom: 15px;
    font-size: 18px;
}

.footer-section p {
    margin-bottom: 8px;
    line-height: 1.6;
}

.footer-bottom {
    text-align: center;
    margin-top: 30px;
    padding-top: 20px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

@media (max-width: 768px) {
    .header {
        flex-direction: column;
        gap: 15px;
    }
    
    .nav ul {
        flex-wrap: wrap;
    }
    
    .products-page,
    .projects-page,
    .contact-info {
        flex-direction: column;
    }
    
    .products-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .projects-grid {
        grid-template-columns: 1fr;
    }
    
    .product-sidebar,
    .product-sidebar {
        width: 100%;
    }
    
    .contact-info {
        flex-direction: column;
    }
    
    .footer-content {
        flex-direction: column;
        text-align: center;
    }
}