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

:root {
    --primary-color: #1a5fb4;
    --secondary-color: #0f3c73;
    --accent-color: #f97316;
    --text-dark: #1f2937;
    --text-light: #6b7280;
    --bg-light: #f9fafb;
    --white: #ffffff;
    --border-color: #e5e7eb;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    color: var(--text-dark);
    line-height: 1.6;
}

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

/* 导航栏 */
.header {
    position: fixed;
    top: 0;
    width: 100%;
    background: var(--white);
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    z-index: 1000;
}

.navbar {
    padding: 1rem 0;
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.logo-text {
    display: flex;
    flex-direction: column;
    line-height: 1.2;
}

.logo-cn {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--primary-color);
    white-space: nowrap;
}

.logo-en {
    font-size: 0.75rem;
    color: var(--text-light);
    white-space: nowrap;
    font-weight: 400;
}

.logo-img {
    height: 45px;
    width: auto;
    display: block;
}

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

.nav-menu a {
    text-decoration: none;
    color: var(--text-dark);
    font-weight: 500;
    transition: color 0.3s;
    padding: 0.5rem 0;
}

.nav-menu a:hover,
.nav-menu a.active {
    color: var(--primary-color);
    border-bottom: 2px solid var(--primary-color);
}

.lang-switch {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.lang-switch a {
    padding: 0;
}

.lang-switch a.active {
    color: var(--primary-color);
    font-weight: 600;
    border-bottom: none;
}


.menu-toggle {
    display: none;
    flex-direction: column;
    cursor: pointer;
}

.menu-toggle span {
    width: 25px;
    height: 3px;
    background: var(--text-dark);
    margin: 3px 0;
    transition: 0.3s;
}

/* 英雄区 */
.hero {
    margin-top: 70px;
    background: linear-gradient(135deg, #1a5fb4 0%, #0f3c73 50%, #0a2f5c 100%);
    color: var(--white);
    padding: 7rem 0;
    text-align: center;
}

.hero-content h2 {
    font-size: 2.7rem;
    font-weight: 700;
    margin-bottom: 1rem;
}

.hero-content p {
    font-size: 1.25rem;
    margin-bottom: 2rem;
    opacity: 0.9;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

.btn {
    display: inline-block;
    padding: 0.75rem 2rem;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 500;
    transition: all 0.3s;
    border: none;
    cursor: pointer;
    font-size: 1rem;
}

.btn-primary {
    background: var(--white);
    color: var(--primary-color);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0,0,0,0.15);
}

.btn-outline {
    background: transparent;
    color: var(--white);
    border: 2px solid var(--white);
}

.btn-outline:hover {
    background: var(--white);
    color: var(--primary-color);
}

.btn-sm {
    padding: 0.5rem 1.5rem;
    font-size: 0.875rem;
}

.btn-full {
    width: 100%;
}

/* 通用区块 */
section {
    padding: 4rem 0;
}

.section-title {
    text-align: center;
    margin-bottom: 3rem;
}

.section-title h3 {
    font-size: 2rem;
    color: var(--text-dark);
    margin-bottom: 0.5rem;
}

.section-title p {
    color: var(--text-light);
    font-size: 1rem;
    text-transform: uppercase;
    letter-spacing: 2px;
}

/* 首页产品区块 */
.products-home {
    background: var(--white);
}

.product-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.product-card {
    background: var(--white);
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 4px 6px rgba(0,0,0,0.05);
    transition: transform 0.3s, box-shadow 0.3s;
    border: 1px solid var(--border-color);
}

.product-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 12px 20px rgba(0,0,0,0.1);
}

.product-image {
    width: 100%;
    height: 180px;
    overflow: hidden;
}

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

.product-image .placeholder-box {
    min-height: 100%;
    background: var(--bg-light);
    border-radius: 0;
}

.product-info {
    padding: 1.5rem;
}

.product-info h4 {
    font-size: 1.25rem;
    margin-bottom: 0.5rem;
    color: var(--text-dark);
}

.product-info p {
    color: var(--text-light);
    margin-bottom: 1rem;
    font-size: 0.95rem;
}

.view-all-wrap {
    text-align: center;
    margin-top: 3rem;
}

/* 核心优势 */
.advantages {
    background: var(--bg-light);
}

.advantage-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
}

.advantage-item {
    background: var(--white);
    padding: 2rem;
    border-radius: 12px;
    text-align: center;
    transition: transform 0.3s;
    border: 1px solid var(--border-color);
}

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

.advantage-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.advantage-item h4 {
    font-size: 1.25rem;
    margin-bottom: 0.75rem;
    color: var(--text-dark);
}

.advantage-item p {
    color: var(--text-light);
    line-height: 1.7;
}

/* CTA区块 */
.cta {
    background: linear-gradient(135deg, #1a5fb4 0%, #0f3c73 50%, #0a2f5c 100%);
    color: var(--white);
    text-align: center;
    padding: 4rem 0;
}

.cta-content h3 {
    font-size: 2rem;
    margin-bottom: 1rem;
}

.cta-content p {
    font-size: 1.1rem;
    margin-bottom: 2rem;
    opacity: 0.9;
}

.cta .btn-primary {
    background: var(--white);
    color: var(--primary-color);
}

/* 子页头部 */
.page-header {
    margin-top: 70px;
    background: var(--bg-light);
    padding: 3rem 0;
    text-align: center;
}

.page-header h2 {
    font-size: 2.2rem;
    color: var(--text-dark);
    margin-bottom: 0.5rem;
}

.page-header p {
    color: var(--text-light);
    font-size: 1rem;
    text-transform: uppercase;
    letter-spacing: 2px;
}

/* 关于我们页面 */
.about-content .about-wrap {
    display: grid;
    grid-template-columns: 1.5fr 1fr;
    gap: 3rem;
    align-items: start;
}

.about-text h3 {
    font-size: 1.5rem;
    margin: 1.5rem 0 1rem;
    color: var(--primary-color);
}

.about-text h3:first-child {
    margin-top: 0;
}

.about-text p {
    color: var(--text-dark);
    line-height: 1.8;
    margin-bottom: 1rem;
}

.about-company-image .placeholder-box.large {
    min-height: 400px;
}

.placeholder-box {
    background: var(--bg-light);
    border: 2px dashed var(--border-color);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-light);
    font-size: 1.1rem;
    min-height: 300px;
    text-align: center;
    line-height: 1.6;
}

.placeholder-box.large {
    min-height: 500px;
}

.detail-product-img {
    width: 100%;
    height: auto;
    max-height: 500px;
    object-fit: contain;
    display: block;
    border-radius: 12px;
    border: 1px solid var(--border-color);
}

.about-full-image {
    width: 100%;
}

.about-full-img {
    width: 100%;
    height: auto;
    display: block;
    border-radius: 12px;
}

/* 产品中心页面 */
.product-full-card {
    display: grid;
    grid-template-columns: 1fr 1.5fr;
    gap: 2rem;
    align-items: center;
    padding: 2rem;
    background: var(--white);
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.05);
    margin-bottom: 2rem;
    border: 1px solid var(--border-color);
}

.product-full-card.reverse {
    grid-template-columns: 1.5fr 1fr;
}

.product-full-card.reverse reverse {
    order: 2;
}

.product-full-image .placeholder-box {
    min-height: 280px;
}

.full-product-img {
    width: 100%;
    height: 280px;
    object-fit: cover;
    display: block;
    border-radius: 12px;
}

.product-full-info h3 {
    font-size: 1.8rem;
    color: var(--text-dark);
    margin-bottom: 0.5rem;
}

.product-subtitle {
    color: var(--text-light);
    font-size: 1rem;
    margin-bottom: 1rem;
    font-style: italic;
}

.product-full-info p {
    color: var(--text-dark);
    line-height: 1.7;
    margin-bottom: 1.5rem;
}

.product-features {
    list-style: none;
    margin-bottom: 1.5rem;
}

.product-features li {
    padding: 0.3rem 0;
    color: var(--text-dark);
}

.product-features li::before {
    content: "✅ ";
}

/* 应用领域 */
.applications {
    background: var(--bg-light);
}

.application-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
}

.application-item {
    background: var(--white);
    padding: 1.5rem;
    border-radius: 12px;
    text-align: center;
    border: 1px solid var(--border-color);
}

.app-icon {
    font-size: 2.5rem;
    margin-bottom: 0.75rem;
}

.application-item h4 {
    font-size: 1.1rem;
    margin-bottom: 0.5rem;
}

.application-item p {
    color: var(--text-light);
    font-size: 0.9rem;
}

/* 联系我们页面 */
.contact-section .contact-wrap {
    display: grid;
    grid-template-columns: 1fr 1.5fr;
    gap: 3rem;
}

.contact-info-block h3 {
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
    color: var(--primary-color);
}

.contact-list {
    list-style: none;
}

.contact-list li {
    padding: 0.75rem 0;
    border-bottom: 1px solid var(--border-color);
}

.contact-list li strong {
    color: var(--text-dark);
    display: inline-block;
    min-width: 80px;
}

.contact-list li span {
    color: var(--text-dark);
}

.contact-list .en-name {
    color: var(--text-light);
    font-size: 0.9rem;
    margin-left: 0;
    display: block;
    margin-top: 0.25rem;
}

.business-note {
    margin-top: 2rem;
    padding: 1.5rem;
    background: var(--bg-light);
    border-radius: 8px;
}

.contact-wrap-full {
    max-width: 600px;
    margin: 0 auto;
}

.business-note h4 {
    margin-bottom: 0.75rem;
    color: var(--primary-color);
}

.contact-form-block {
    background: var(--white);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.05);
    border: 1px solid var(--border-color);
}

.contact-form-block h3 {
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
    color: var(--text-dark);
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: var(--text-dark);
}

.form-group input,
.form-group textarea,
.form-group select {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    font-family: inherit;
    font-size: 1rem;
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
    outline: none;
    border-color: var(--primary-color);
}

/* 产品详情页 */
.product-detail .product-detail-wrap {
    display: grid;
    grid-template-columns: 1fr 1.8fr;
    gap: 3rem;
    align-items: start;
}

.product-detail-image .placeholder-box.large {
    min-height: 400px;
}

.product-detail-info h2 {
    font-size: 2.2rem;
    color: var(--text-dark);
    margin-bottom: 0.5rem;
}

.product-en-name {
    color: var(--text-light);
    font-size: 1.1rem;
    font-style: italic;
    margin-bottom: 1rem;
}

.product-desc {
    font-size: 1.05rem;
    color: var(--text-dark);
    line-height: 1.7;
    margin-bottom: 2rem;
}

.product-detail-info h3 {
    font-size: 1.4rem;
    margin: 1.5rem 0 1rem;
    color: var(--primary-color);
}

.table-responsive {
    overflow-x: auto;
}

.product-table {
    width: 100%;
    border-collapse: collapse;
    border: 1px solid var(--border-color);
}

.product-table thead {
    background: var(--bg-light);
}

.product-table th,
.product-table td {
    padding: 0.75rem 0.5rem;
    border: 1px solid var(--border-color);
    text-align: center;
    font-size: 0.9rem;
}

.product-table th {
    font-weight: 600;
    color: var(--text-dark);
}

.usage-list {
    list-style: none;
}

.usage-list li {
    padding: 0.5rem 0;
    line-height: 1.7;
}

.property-list {
    list-style: none;
}

.property-list li {
    padding: 0.3rem 0;
    line-height: 1.7;
}

.cta-product {
    margin-top: 2.5rem;
    display: flex;
    gap: 1rem;
}

/* 页脚 */
.footer {
    background: var(--text-dark);
    color: var(--white);
    padding: 2.5rem 0;
}

.footer-content {
    text-align: center;
}

.footer-info h3 {
    margin-bottom: 0.5rem;
    font-size: 1.2rem;
}

.footer-info p {
    opacity: 0.7;
    margin-bottom: 1rem;
}

.footer-copyright {
    border-top: 1px solid rgba(255,255,255,0.1);
    padding-top: 1rem;
    opacity: 0.6;
    font-size: 0.9rem;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        left: -100%;
        top: 70px;
        flex-direction: column;
        background: var(--white);
        width: 100%;
        text-align: center;
        transition: 0.3s;
        box-shadow: 0 10px 27px rgba(0,0,0,0.05);
        padding: 2rem 0;
    }

    .nav-menu.active {
        left: 0;
    }

    .menu-toggle {
        display: flex;
    }

    .hero {
        padding: 4rem 0;
    }

    .hero-content h2 {
        font-size: 2rem;
    }

    .product-full-card,
    .product-full-card.reverse,
    .about-content .about-wrap,
    .contact-section .contact-wrap,
    .product-detail .product-detail-wrap {
        grid-template-columns: 1fr;
    }

    section {
        padding: 3rem 0;
    }
}