:root {
    --primary-color: #1a6dcc;
    --secondary-color: #0d4d9c;
    --accent-color: #ff6b00;
    --light-bg: #f8f9fa;
    --dark-bg: #343a40;
    --text-dark: #212529;
    --text-light: #6c757d;
    --border-color: #dee2e6;
    --gradient-primary: linear-gradient(135deg, #1a6dcc 0%, #0d4d9c 100%);
}

body {
    font-family: 'Roboto', 'Segoe UI', sans-serif;
    color: var(--text-dark);
    line-height: 1.6;
}

/* Enhanced Navigation */
.navbar-brand img {
    height: 50px;
}

.navbar {
    background-color: rgba(255, 255, 255, 0.98);
    backdrop-filter: blur(10px);
    box-shadow: 0 2px 20px rgba(0, 0, 0, 0.08);
}

.nav-link {
    font-weight: 500;
    transition: all 0.3s ease;
    position: relative;
}

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

.nav-link:after {
    content: '';
    position: absolute;
    width: 0;
    height: 2px;
    bottom: 0;
    left: 50%;
    background-color: var(--primary-color);
    transition: all 0.3s ease;
}

.nav-link:hover:after {
    width: 100%;
    left: 0;
}

.dropdown-menu {
    border-radius: 0.75rem;
    border: 1px solid var(--border-color);
    box-shadow: 0 10px 30px rgba(0,0,0,0.12);
    margin-top: 0.5rem;
}

.dropdown-item:hover {
    background-color: rgba(26, 109, 204, 0.08);
    color: var(--primary-color);
}

/* Enhanced Hero Banner */
.hero-banner {
    background: linear-gradient(135deg, rgba(13, 77, 156, 0.9) 0%, rgba(26, 109, 204, 0.9) 100%),
    url('https://www.huahangfilters.com/wp-content/themes/coverweb/d/images/sub_banner_pro_det.png');
    background-size: cover;
    background-position: center;
    color: white;
    padding: 100px 0;
    margin-bottom: 2rem;
    position: relative;
    overflow: hidden;
}

.hero-banner:before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: radial-gradient(circle at 70% 20%, rgba(255, 255, 255, 0.1) 0%, transparent 70%);
}

.hero-banner h1 {
    text-shadow: 0 2px 10px rgba(0, 0, 0, 0.2);
}

/* Product Images with Enhanced Styling */
.product-image-main {
    border: 1px solid var(--border-color);
    border-radius: 0.75rem;
    overflow: hidden;
    background-color: white;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.08);
    transition: all 0.3s ease;
}

.product-image-main:hover {
    box-shadow: 0 15px 40px rgba(0, 0, 0, 0.15);
}

.product-image-slider {
    height: 400px; /* 设置固定高度 */
}

.product-image-slider .swiper-slide {
    height: 100%; /* 让slide占满slider高度 */
}

.product-image-slider .swiper-slide img {
    width: 100%;
    height: 100%;
    object-fit: contain; /* 或 contain，根据需要选择 */
}

.product-image-slider .swiper-slide {
    cursor: pointer;
    transition: transform 0.3s ease;
}

.product-image-slider .swiper-slide:hover {
    transform: scale(1.02);
}

.product-thumbnails .thumbnail-item {
    border: 2px solid transparent;
    border-radius: 0.5rem;
    overflow: hidden;
    cursor: pointer;
    transition: all 0.3s ease;
    background-color: white;
    padding: 3px;
    text-align: center;
}

.img-fluid {
    max-width: 100%;
    height: 80px;
    object-fit: contain;
}

.img-fluid-about {
    max-width: 100%;
    height: 100%;
    object-fit: fill;
}

.product-thumbnails .thumbnail-item.active,
.product-thumbnails .thumbnail-item:hover {
    border-color: var(--primary-color);
    transform: translateY(-3px);
    box-shadow: 0 5px 15px rgba(26, 109, 204, 0.2);
}

/* Enhanced Product Title */
.product-title {
    color: var(--text-dark);
    font-weight: 800;
    margin-bottom: 1.5rem;
    position: relative;
    display: inline-block;
}

.product-title:after {
    content: '';
    position: absolute;
    bottom: -8px;
    left: 0;
    width: 60px;
    height: 4px;
    background: var(--gradient-primary);
    border-radius: 2px;
}

/* Enhanced Specification Items */
.spec-item {
    padding: 0.9rem 0;
    border-bottom: 1px solid var(--border-color);
    transition: background-color 0.2s ease;
    border-radius: 0.25rem;
    padding-left: 0.75rem;
    padding-right: 0.75rem;
}

.spec-item:hover {
    background-color: rgba(248, 249, 250, 0.8);
}

.spec-item:last-child {
    border-bottom: none;
}

.spec-label {
    font-weight: 600;
    color: var(--text-dark);
}

.spec-value {
    color: var(--text-light);
    font-weight: 500;
}

/* Enhanced Action Buttons */
.action-btn {
    padding: 0.85rem 1.75rem;
    font-weight: 600;
    border-radius: 0.5rem;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
    z-index: 1;
}

.btn-primary-custom {
    background: var(--gradient-primary);
    border: none;
    color: white;
}

.btn-primary-custom:before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
    transition: all 0.6s ease;
    z-index: -1;
}

.btn-primary-custom:hover:before {
    left: 100%;
}

.btn-primary-custom:hover {
    transform: translateY(-3px);
    box-shadow: 0 10px 20px rgba(26, 109, 204, 0.3);
}

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

.btn-outline-primary-custom:hover {
    background-color: var(--primary-color);
    color: white;
    transform: translateY(-3px);
    box-shadow: 0 8px 15px rgba(26, 109, 204, 0.2);
}

/* Section Styling */
.section-title {
    position: relative;
    padding-bottom: 1.25rem;
    margin-bottom: 2.5rem;
}

.section-title:after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 70px;
    height: 4px;
    background: var(--gradient-primary);
    border-radius: 2px;
}

.section-title.text-center:after {
    left: 50%;
    transform: translateX(-50%);
}

/* Enhanced Tab Navigation */
.tab-nav {
    border-bottom: 2px solid var(--border-color);
    background-color: white;
    border-radius: 0.75rem 0.75rem 0 0;
    padding: 0 0.5rem;
}

.tab-nav .nav-link {
    border: none;
    color: var(--text-light);
    font-weight: 600;
    padding: 1.1rem 2rem;
    position: relative;
    margin: 0 0.25rem;
    border-radius: 0.5rem 0.5rem 0 0;
    transition: all 0.3s ease;
}

.tab-nav .nav-link:hover {
    color: var(--primary-color);
    background-color: rgba(26, 109, 204, 0.05);
}

.tab-nav .nav-link.active {
    color: var(--primary-color);
    background-color: transparent;
}

.tab-nav .nav-link.active:after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 100%;
    height: 3px;
    background: var(--gradient-primary);
    border-radius: 2px 2px 0 0;
}

/* Enhanced Feature List */
.feature-list li {
    margin-bottom: 0.9rem;
    padding-left: 2rem;
    position: relative;
}

.feature-list li:before {
    content: '✓';
    position: absolute;
    left: 0;
    color: white;
    font-weight: bold;
    background: var(--gradient-primary);
    width: 24px;
    height: 24px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.8rem;
}

/* Enhanced Specification Table */
.spec-table {
    width: 100%;
    border-collapse: separate;
    border-spacing: 0;
    border-radius: 0.75rem;
    overflow: hidden;
}

.spec-table th, .spec-table td {
    padding: 1rem;
    border: 1px solid var(--border-color);
    text-align: center;
}

.spec-table th {
    background: var(--gradient-primary);
    color: white;
    font-weight: 600;
    border: none;
}

.spec-table tr:nth-child(even) {
    background-color: rgba(248, 249, 250, 0.5);
}

/* Enhanced CTA Section */
.cta-section {
    background: var(--gradient-primary);
    color: white;
    padding: 5rem 0;
    position: relative;
    overflow: hidden;
}

.cta-section:before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image: url('data:image/svg+xml,<svg width="60" height="60" viewBox="0 0 60 60" xmlns="http://www.w3.org/2000/svg"><path d="M54 50c-3-3-6-4-10-2-4 1-7 5-11 6-5 0-10-1-14-4-5-3-8-8-12-12-4-4-9-7-14-9-5-2-11-2-16-2" stroke="white" stroke-width="1" fill="none" opacity="0.1"/></svg>');
    background-size: 600px;
    opacity: 0.1;
}

/* Enhanced Product Cards */
.product-card {
    border: 1px solid var(--border-color);
    border-radius: 0.75rem;
    overflow: hidden;
    transition: all 0.4s ease;
    height: 100%;
    background-color: white;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
}

.product-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 30px rgba(0, 0, 0, 0.1);
    border-color: var(--primary-color);
}

.product-card-img {
    height: 220px;
    object-fit:contain;
    width: 100%;
    transition: transform 0.5s ease;
}

.product-card:hover .product-card-img {
    transform: scale(1.05);
}

.product-card-body {
    padding: 1.75rem;
}

.product-card-title {
    font-weight: 700;
    font-size: 1.15rem;
    margin-bottom: 0.85rem;
    color: var(--text-dark);
    line-height: 1.4;
}

.product-card-price {
    color: var(--primary-color);
    font-weight: 700;
    font-size: 1.2rem;
}

.product-card-badge {
    position: absolute;
    top: 15px;
    right: 15px;
    background: var(--accent-color);
    color: white;
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 600;
}


.social-icons a {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background-color: rgba(255,255,255,0.1);
    border-radius: 50%;
    text-align: center;
    margin-right: 0.75rem;
    transition: all 0.3s ease;
}

.social-icons a:hover {
    background: var(--gradient-primary);
    transform: translateY(-5px) scale(1.1);
    color: white;
}

/* Floating Elements */
.float-contact {
    position: fixed;
    bottom: 30px;
    right: 30px;
    z-index: 1000;
}

.float-contact-btn {
    width: 65px;
    height: 65px;
    border-radius: 50%;
    background: linear-gradient(135deg, #25D366 0%, #128C7E 100%);
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.75rem;
    box-shadow: 0 8px 25px rgba(37, 211, 102, 0.4);
    transition: all 0.3s ease;
}

.float-contact-btn:hover {
    transform: scale(1.1) rotate(5deg);
    box-shadow: 0 12px 30px rgba(37, 211, 102, 0.6);
    color: white;
}

.back-to-top {
    position: fixed;
    bottom: 110px;
    right: 30px;
    z-index: 1000;
    opacity: 0;
    visibility: hidden;
    transition: all 0.4s ease;
}

.back-to-top-btn {
    width: 55px;
    height: 55px;
    border-radius: 50%;
    background: var(--gradient-primary);
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.35rem;
    box-shadow: 0 8px 20px rgba(26, 109, 204, 0.4);
    transition: all 0.3s ease;
}

.back-to-top-btn:hover {
    transform: translateY(-5px);
    box-shadow: 0 12px 25px rgba(26, 109, 204, 0.6);
    color: white;
}

/* Image Lightbox */
.lightbox {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.9);
    z-index: 1100;
    display: none;
    justify-content: center;
    align-items: center;
}

.lightbox.active {
    display: flex;
}

.lightbox-content {
    max-width: 90%;
    max-height: 90%;
    position: relative;
}

.lightbox-img {
    max-width: 100%;
    max-height: 90vh;
    border-radius: 0.5rem;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.5);
}

.lightbox-close {
    position: absolute;
    top: -50px;
    right: 0;
    background: rgba(255, 255, 255, 0.2);
    color: white;
    border: none;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    cursor: pointer;
    transition: all 0.3s ease;
}

.lightbox-close:hover {
    background: rgba(255, 255, 255, 0.3);
    transform: rotate(90deg);
}

.lightbox-nav {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    background: rgba(255, 255, 255, 0.2);
    color: white;
    border: none;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    cursor: pointer;
    transition: all 0.3s ease;
}

.lightbox-nav:hover {
    background: rgba(255, 255, 255, 0.3);
}

.lightbox-prev {
    left: 20px;
}

.lightbox-next {
    right: 20px;
}

/* Responsive Design */
@media (max-width: 768px) {
    .hero-banner {
        padding: 70px 0;
    }

    .product-title {
        font-size: 1.75rem;
    }

    .tab-nav .nav-link {
        padding: 0.75rem 1rem;
        font-size: 0.9rem;
    }

    .float-contact {
        bottom: 20px;
        right: 20px;
    }

    .float-contact-btn {
        width: 55px;
        height: 55px;
        font-size: 1.5rem;
    }

    .back-to-top {
        bottom: 85px;
        right: 20px;
    }

    .back-to-top-btn {
        width: 48px;
        height: 48px;
        font-size: 1.2rem;
    }

    .lightbox-nav {
        width: 40px;
        height: 40px;
        font-size: 1.2rem;
    }

    .lightbox-prev {
        left: 10px;
    }

    .lightbox-next {
        right: 10px;
    }


}

/* Animation Classes */
.fade-in {
    animation: fadeIn 0.8s ease forwards;
}

.slide-up {
    animation: slideUp 0.6s ease forwards;
}

.mb-3{
    color: #ffffff;
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

@keyframes slideUp {
    from { transform: translateY(30px); opacity: 0; }
    to { transform: translateY(0); opacity: 1; }
}

/* Related Products Slider */
.related-products {
    background: linear-gradient(135deg, #f8f9fa 0%, #e9ecef 100%);
    padding: 80px 0;
    position: relative;
}

.related-slider-container {
    position: relative;
    padding: 20px 40px;
}

.related-slider {
    overflow: hidden;
}

/* Custom Swiper Navigation */
.slider-nav-btn {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background: white;
    border: 2px solid var(--primary-color);
    color: var(--primary-color);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    cursor: pointer;
    z-index: 10;
    transition: all 0.3s ease;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

.slider-nav-btn:hover {
    background: var(--gradient-primary);
    color: white;
    transform: translateY(-50%) scale(1.1);
    box-shadow: 0 8px 20px rgba(26, 109, 204, 0.3);
}

.slider-nav-btn.prev {
    left: 0;
}

.slider-nav-btn.next {
    right: 0;
}

/* Swiper Pagination Customization */
.related-slider .swiper-pagination {
    position: relative;
    margin-top: 30px;
}

.related-slider .swiper-pagination-bullet {
    width: 12px;
    height: 12px;
    background: #ddd;
    opacity: 1;
    transition: all 0.3s ease;
}

.related-slider .swiper-pagination-bullet-active {
    background: var(--primary-color);
    transform: scale(1.2);
}

.alert-message {
    position: fixed;
    top: 20px;
    right: 20px;
    z-index: 9999;
    min-width: 300px;
    display: none;
}
.loading-spinner {
    display: none;
    text-align: center;
    padding: 10px;
}