/* ===== COMETEC China 官网样式 - 增强版 ===== */
:root {
    --primary-red: #8B1A1A;
    --primary-red-light: #a82525;
    --primary-red-dark: #6b1414;
    --dark-gray: #2d2d2d;
    --darker-gray: #1a1a1a;
    --medium-gray: #555;
    --light-gray: #f5f5f5;
    --border-gray: #e0e0e0;
    --white: #ffffff;
    --text-dark: #333;
    --text-light: #666;
    --text-muted: #999;
    --shadow-sm: 0 2px 8px rgba(0,0,0,0.08);
    --shadow-md: 0 4px 16px rgba(0,0,0,0.12);
    --shadow-lg: 0 8px 32px rgba(0,0,0,0.16);
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html { scroll-behavior: smooth; }

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
    color: var(--text-dark);
    line-height: 1.7;
    background: var(--white);
    overflow-x: hidden;
}

.container {
    max-width: 1240px;
    margin: 0 auto;
    padding: 0 24px;
}

a { text-decoration: none; color: inherit; transition: var(--transition); }
ul { list-style: none; }
img { max-width: 100%; display: block; }

/* ===== 顶部通栏 ===== */
.top-bar {
    background: var(--primary-red);
    color: var(--white);
    font-size: 13px;
    padding: 8px 0;
    position: relative;
    z-index: 100;
}
.top-bar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}
.top-bar-left span { margin-right: 24px; opacity: 0.95; }
.top-bar-left span:last-child { margin-right: 0; }
.lang-switch a {
    color: rgba(255,255,255,0.7);
    margin-left: 12px;
    font-weight: 500;
}
.lang-switch a.active,
.lang-switch a:hover { color: var(--white); }

/* ===== 主导航 ===== */
.main-nav {
    background: var(--white);
    box-shadow: var(--shadow-sm);
    position: sticky;
    top: 0;
    z-index: 999;
    transition: var(--transition);
}
.main-nav.scrolled {
    box-shadow: var(--shadow-md);
    background: rgba(255,255,255,0.98);
    backdrop-filter: blur(10px);
}
.main-nav .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 72px;
}
.logo {
    font-size: 26px;
    font-weight: 800;
    color: var(--primary-red);
    letter-spacing: 1px;
    line-height: 1.1;
}
.logo-sub {
    display: block;
    font-size: 11px;
    color: var(--text-light);
    font-weight: 500;
    letter-spacing: 2px;
    margin-top: 2px;
}
.nav-menu {
    display: flex;
    gap: 4px;
}
.nav-menu > li { position: relative; }
.nav-menu > li > a {
    display: block;
    padding: 26px 18px;
    font-size: 14px;
    font-weight: 600;
    color: var(--text-dark);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    position: relative;
}
.nav-menu > li > a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    width: 0;
    height: 3px;
    background: var(--primary-red);
    transition: var(--transition);
    transform: translateX(-50%);
}
.nav-menu > li > a:hover::after,
.nav-menu > li > a.active::after { width: 60%; }
.nav-menu > li > a:hover,
.nav-menu > li > a.active { color: var(--primary-red); }

.mobile-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
    padding: 8px;
}
.mobile-toggle span {
    width: 24px;
    height: 2px;
    background: var(--text-dark);
    transition: var(--transition);
}

/* ===== 产品中心下拉菜单 ===== */
.nav-menu > li.has-dropdown > a::after {
    content: ' ▾';
    font-size: 10px;
    margin-left: 4px;
    opacity: .7;
}
.nav-menu > li.has-dropdown > a {
    display: block;
    padding-right: 14px;
}
.dropdown {
    position: absolute;
    top: 100%;
    left: 0;
    min-width: 240px;
    background: var(--white);
    box-shadow: var(--shadow-md);
    border-top: 3px solid var(--primary-red);
    border-radius: 0 0 6px 6px;
    opacity: 0;
    visibility: hidden;
    transform: translateY(10px);
    transition: all .25s cubic-bezier(0.4,0,0.2,1);
    padding: 8px 0;
    z-index: 100;
    list-style: none;
}
.dropdown li { width: 100%; }
.dropdown li a {
    display: block;
    padding: 11px 22px;
    color: var(--text-dark);
    font-size: 14px;
    border-left: 3px solid transparent;
    transition: all .2s;
}
.dropdown li a::after { display: none; }
.nav-menu > li.has-dropdown:hover .dropdown,
.nav-menu > li.has-dropdown:focus-within .dropdown {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}
.dropdown li a:hover {
    background: rgba(176,30,40,0.06);
    color: var(--primary-red);
    border-left-color: var(--primary-red);
    padding-left: 26px;
}

/* ===== Hero Banner 视差滚动 ===== */
.hero {
    position: relative;
    min-height: 560px;
    display: flex;
    align-items: center;
    overflow: hidden;
    background: var(--darker-gray);
}
.hero-bg {
    position: absolute;
    top: 0; left: 0; right: 0; bottom: 0;
    background-image: 
        linear-gradient(135deg, rgba(26,26,26,0.6) 0%, rgba(45,45,45,0.8) 100%),
        url("../images/i1.jpg");
    background-size: cover;
    background-position: center;
    background-attachment: fixed;
    will-change: transform;
}
.hero-pattern {
    position: absolute;
    top: 0; left: 0; right: 0; bottom: 0;
    background-image: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M30 5L55 20v20L30 55 5 40V20z' fill='none' stroke='%23ffffff' stroke-width='0.5' opacity='0.08'/%3E%3C/svg%3E");
    opacity: 0.6;
}
.hero-content {
    position: relative;
    z-index: 2;
    color: var(--white);
    max-width: 780px;
    animation: fadeInUp 1s ease-out;
}
.hero-subtitle {
    display: inline-block;
    font-size: 14px;
    font-weight: 600;
    letter-spacing: 3px;
    text-transform: uppercase;
    color: var(--white);
    margin-bottom: 20px;
    padding-bottom: 10px;
    border-bottom: 2px solid var(--primary-red);
}
.hero h1 {
    font-size: 44px;
    font-weight: 800;
    line-height: 1.25;
    margin-bottom: 24px;
    letter-spacing: 1px;
}
.hero p {
    font-size: 17px;
    line-height: 1.9;
    opacity: 0.9;
    margin-bottom: 32px;
}
.hero-btns { display: flex; gap: 16px; flex-wrap: wrap; }
.btn-primary {
    display: inline-block;
    padding: 14px 36px;
    background: var(--primary-red);
    color: var(--white);
    font-weight: 600;
    font-size: 15px;
    border: 2px solid var(--primary-red);
    border-radius: 2px;
    cursor: pointer;
    transition: var(--transition);
    letter-spacing: 1px;
}
.btn-primary:hover {
    background: var(--primary-red-dark);
    border-color: var(--primary-red-dark);
    transform: translateY(-2px);
    box-shadow: 0 8px 24px rgba(139,26,26,0.4);
}
.btn-outline {
    display: inline-block;
    padding: 14px 36px;
    background: transparent;
    color: var(--white);
    font-weight: 600;
    font-size: 15px;
    border: 2px solid rgba(255,255,255,0.5);
    border-radius: 2px;
    cursor: pointer;
    transition: var(--transition);
    letter-spacing: 1px;
}
.btn-outline:hover {
    background: var(--white);
    color: var(--text-dark);
    border-color: var(--white);
    transform: translateY(-2px);
}
.hero-scroll-indicator {
    position: absolute;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%);
    z-index: 3;
    animation: bounce 2s infinite;
}
.hero-scroll-indicator span {
    display: block;
    width: 24px;
    height: 40px;
    border: 2px solid rgba(255,255,255,0.5);
    border-radius: 12px;
    position: relative;
}
.hero-scroll-indicator span::before {
    content: '';
    position: absolute;
    top: 8px;
    left: 50%;
    transform: translateX(-50%);
    width: 4px;
    height: 8px;
    background: rgba(255,255,255,0.8);
    border-radius: 2px;
    animation: scrollDot 1.5s infinite;
}

/* ===== 页面Hero ===== */
.page-hero {
    position: relative;
    min-height: 390px;
    display: flex;
    align-items: center;
    overflow: hidden;
    background: var(--darker-gray);
    text-align: center;
}
.page-hero-bg {
    position: absolute;
    top: 0; left: 0; right: 0; bottom: 0;
    background-image: 
        linear-gradient(135deg, rgba(26,26,26,0.6) 0%, rgba(45,45,45,0.8) 100%),
        url( "../images/c01.jpg");
    background-size: cover;
    background-position: center;
    background-attachment: fixed;
}
.page-hero .container { position: relative; z-index: 2; color: var(--white); }
.page-hero h1 {
    font-size: 40px;
    font-weight: 800;
    margin-bottom: 12px;
    letter-spacing: 2px;
    animation: fadeInUp 0.8s ease-out;
}
.page-hero p {
    font-size: 18px;
    opacity: 0.85;
    animation: fadeInUp 0.8s ease-out 0.2s both;
}

/* ===== 通用区块 ===== */
.content-section {
    padding: 80px 0;
    position: relative;
}
.alt-bg { background: var(--light-gray); }

.section-title {
    text-align: center;
    font-size: 32px;
    font-weight: 800;
    color: var(--text-dark);
    margin-bottom: 16px;
    letter-spacing: 1px;
    position: relative;
}
.section-title::after {
    content: '';
    display: block;
    width: 60px;
    height: 3px;
    background: var(--primary-red);
    margin: 16px auto 0;
}
.section-subtitle {
    text-align: center;
    max-width: 800px;
    margin: 0 auto 50px;
    color: var(--text-light);
    font-size: 16px;
    line-height: 1.9;
}

/* ===== 数据统计区 ===== */
.stats-section {
    background: var(--primary-red);
    padding: 60px 0;
    position: relative;
    overflow: hidden;
}
.stats-section::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0; bottom: 0;
    background-image: url("");
}
.stats-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
    position: relative;
    z-index: 2;
}
.stat-card {
    background: rgba(0,0,0,0.25);
    padding: 36px 24px;
    text-align: center;
    border-radius: 4px;
    transition: var(--transition);
    border: 1px solid rgba(255,255,255,0.1);
}
.stat-card:hover {
    transform: translateY(-6px);
    background: rgba(0,0,0,0.35);
}
.stat-icon { font-size: 36px; margin-bottom: 12px; }
.stat-number {
    font-size: 48px;
    font-weight: 800;
    color: var(--white);
    line-height: 1;
    margin-bottom: 8px;
}
.stat-label {
    color: rgba(255,255,255,0.85);
    font-size: 15px;
    font-weight: 500;
}

/* ===== 专长标签 ===== */
.specialty-tag {
    background: var(--primary-red);
    padding: 16px 0;
    text-align: center;
}
.specialty-tag span {
    color: var(--white);
    font-size: 14px;
    font-weight: 600;
    letter-spacing: 2px;
}

/* ===== 左右图文布局 ===== */
.industry-detail {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 50px;
    align-items: center;
    margin-bottom: 60px;
}
.industry-detail:last-child { margin-bottom: 0; }
.industry-detail-img {
    height: 360px;
    background-size: cover;
    background-position: center;
    border-radius: 4px;
    box-shadow: var(--shadow-lg);
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}
.industry-detail-img::after {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0; bottom: 0;
    background: linear-gradient(135deg, transparent 50%, rgba(139,26,26,0.1) 100%);
}
.industry-detail-img:hover { transform: scale(1.02); }
.industry-detail-content h3 {
    font-size: 24px;
    font-weight: 700;
    margin-bottom: 16px;
    color: var(--text-dark);
}
.industry-detail-content p {
    color: var(--text-light);
    margin-bottom: 14px;
    line-height: 1.9;
}
.industry-detail-content ul { margin-top: 16px; }
.industry-detail-content li {
    padding: 8px 0 8px 28px;
    position: relative;
    color: var(--text-light);
}
.industry-detail-content li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--primary-red);
    font-weight: 700;
    font-size: 16px;
}

/* ===== 专业能力区 ===== */
.expertise-section {
    background: var(--light-gray);
    padding: 80px 0;
}
.expertise-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 50px;
    align-items: start;
}
.expertise-intro h2 {
    font-size: 30px;
    font-weight: 800;
    margin-bottom: 20px;
    color: var(--text-dark);
}
.expertise-intro p {
    color: var(--text-light);
    margin-bottom: 16px;
    line-height: 1.9;
}
.expertise-cards { display: flex; flex-direction: column; gap: 20px; }
.expertise-card {
    background: var(--white);
    padding: 24px;
    border-radius: 4px;
    box-shadow: var(--shadow-sm);
    display: flex;
    gap: 18px;
    transition: var(--transition);
    border-left: 4px solid var(--primary-red);
}
.expertise-card:hover {
    transform: translateX(6px);
    box-shadow: var(--shadow-md);
}
.expertise-card-icon {
    font-size: 32px;
    flex-shrink: 0;
    width: 50px;
    height: 50px;
    background: var(--light-gray);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
}
.expertise-card h3 {
    font-size: 16px;
    font-weight: 700;
    margin-bottom: 8px;
    color: var(--text-dark);
}
.expertise-card p {
    font-size: 14px;
    color: var(--text-light);
    line-height: 1.7;
}

/* ===== 服务网格 ===== */
.service-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 28px;
}
.service-card {
    background: var(--white);
    padding: 36px 28px;
    border-radius: 4px;
    box-shadow: var(--shadow-sm);
    text-align: center;
    transition: var(--transition);
    border-top: 3px solid transparent;
}
.service-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-lg);
    border-top-color: var(--primary-red);
}
.service-icon {
    font-size: 44px;
    margin-bottom: 18px;
    display: inline-block;
    transition: var(--transition);
}
.service-card:hover .service-icon { transform: scale(1.15); }
.service-card h3 {
    font-size: 18px;
    font-weight: 700;
    margin-bottom: 12px;
    color: var(--text-dark);
}
.service-card p {
    color: var(--text-light);
    font-size: 14px;
    line-height: 1.8;
}

/* ===== 产品网格 ===== */
.product-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 30px;
}
.product-item {
    background: var(--white);
    border-radius: 4px;
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}
.product-item:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-lg);
}
.product-item-img {
    height: 220px;
    background-size: cover;
    background-position: center;
    transition: var(--transition);
}
.product-item:hover .product-item-img { transform: scale(1.05); }
.product-item-body { padding: 24px; }
.product-item-body h3 {
    font-size: 18px;
    font-weight: 700;
    margin-bottom: 10px;
    color: var(--text-dark);
}
.product-item-body p {
    color: var(--text-light);
    font-size: 14px;
    line-height: 1.8;
    margin-bottom: 14px;
}
.learn-more {
    color: var(--primary-red);
    font-size: 13px;
    font-weight: 600;
    display: inline-block;
}
.learn-more:hover { letter-spacing: 1px; }

/* ===== 时间轴 ===== */
.timeline {
    position: relative;
    max-width: 800px;
    margin: 0 auto;
    padding-left: 40px;
}
.timeline::before {
    content: '';
    position: absolute;
    left: 12px;
    top: 0;
    bottom: 0;
    width: 2px;
    background: var(--border-gray);
}
.timeline-item {
    position: relative;
    margin-bottom: 36px;
    padding-left: 30px;
}
.timeline-item::before {
    content: '';
    position: absolute;
    left: -34px;
    top: 6px;
    width: 16px;
    height: 16px;
    background: var(--primary-red);
    border-radius: 50%;
    border: 3px solid var(--white);
    box-shadow: 0 0 0 2px var(--primary-red);
}
.timeline-year {
    font-size: 20px;
    font-weight: 800;
    color: var(--primary-red);
    margin-bottom: 6px;
}
.timeline-content h4 {
    font-size: 17px;
    font-weight: 700;
    margin-bottom: 8px;
    color: var(--text-dark);
}
.timeline-content p {
    color: var(--text-light);
    line-height: 1.8;
}

/* ===== CTA ===== */
.cta-section {
    background: var(--primary-red);
    padding: 60px 0;
    text-align: center;
    position: relative;
    overflow: hidden;
}
.cta-section::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0; bottom: 0;
    background-image: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M30 5L55 20v20L30 55 5 40V20z' fill='none' stroke='%23ffffff' stroke-width='0.5' opacity='0.08'/%3E%3C/svg%3E");
}
.cta-section .container { position: relative; z-index: 2; }
.cta-section h2 {
    color: var(--white);
    font-size: 30px;
    font-weight: 700;
    margin-bottom: 24px;
    letter-spacing: 1px;
}
.cta-btn {
    display: inline-block;
    padding: 14px 40px;
    background: var(--white);
    color: var(--primary-red);
    font-weight: 700;
    font-size: 15px;
    border: 2px solid var(--white);
    border-radius: 2px;
    cursor: pointer;
    transition: var(--transition);
    letter-spacing: 1px;
}
.cta-btn:hover {
    background: transparent;
    color: var(--white);
    transform: translateY(-2px);
    box-shadow: 0 8px 24px rgba(0,0,0,0.2);
}

/* ===== 全球服务 ===== */
.global-service {
    background: var(--darker-gray);
    padding: 70px 0;
    color: var(--white);
    text-align: center;
}
.global-service h2 {
    font-size: 30px;
    font-weight: 800;
    margin-bottom: 14px;
}
.global-service > .container > p {
    color: rgba(255,255,255,0.75);
    max-width: 700px;
    margin: 0 auto 40px;
    line-height: 1.9;
}
.global-regions {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
}
.region-card {
    background: rgba(255,255,255,0.06);
    padding: 28px 20px;
    border-radius: 4px;
    border: 1px solid rgba(255,255,255,0.1);
    transition: var(--transition);
}
.region-card:hover {
    background: rgba(255,255,255,0.1);
    transform: translateY(-4px);
}
.region-icon { font-size: 32px; margin-bottom: 12px; }
.region-card h4 {
    font-size: 16px;
    font-weight: 700;
    margin-bottom: 8px;
}
.region-card p {
    font-size: 13px;
    color: rgba(255,255,255,0.7);
    line-height: 1.7;
}

/* ===== 联系页 ===== */
.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1.3fr;
    gap: 40px;
    margin-bottom: 50px;
}
.contact-info-card {
    background: var(--dark-gray);
    color: var(--white);
    padding: 40px;
    border-radius: 4px;
}
.contact-info-card h3 {
    font-size: 22px;
    font-weight: 700;
    margin-bottom: 28px;
    padding-bottom: 14px;
    border-bottom: 2px solid var(--primary-red);
}
.contact-info-item {
    display: flex;
    gap: 16px;
    margin-bottom: 24px;
}
.contact-info-icon {
    font-size: 22px;
    flex-shrink: 0;
    width: 44px;
    height: 44px;
    background: rgba(255,255,255,0.1);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
}
.contact-info-item h4 {
    font-size: 14px;
    font-weight: 600;
    margin-bottom: 4px;
    color: var(--white);
}
.contact-info-item p {
    font-size: 14px;
    color: rgba(255,255,255,0.75);
    line-height: 1.7;
}
.contact-form {
    background: var(--white);
    padding: 40px;
    border-radius: 4px;
    box-shadow: var(--shadow-sm);
}
.contact-form h3 {
    font-size: 22px;
    font-weight: 700;
    margin-bottom: 24px;
    color: var(--text-dark);
}
.form-group { margin-bottom: 20px; }
.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}
.form-group label {
    display: block;
    font-size: 13px;
    font-weight: 600;
    margin-bottom: 8px;
    color: var(--text-dark);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}
.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 12px 16px;
    border: 1px solid var(--border-gray);
    border-radius: 2px;
    font-size: 14px;
    font-family: inherit;
    transition: var(--transition);
    background: var(--white);
}
.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-red);
    box-shadow: 0 0 0 3px rgba(139,26,26,0.1);
}
.form-group textarea { min-height: 120px; resize: vertical; }
.submit-btn {
    width: 100%;
    padding: 14px;
    background: var(--primary-red);
    color: var(--white);
    border: none;
    border-radius: 2px;
    font-size: 15px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    letter-spacing: 1px;
}
.submit-btn:hover {
    background: var(--primary-red-dark);
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(139,26,26,0.3);
}

.map-placeholder {
    background: var(--light-gray);
    padding: 60px 20px;
    border-radius: 4px;
    border: 2px dashed var(--border-gray);
}

/* ===== 页脚 ===== */
.footer {
    background: var(--darker-gray);
    color: rgba(255,255,255,0.7);
    padding: 60px 0 0;
}
.footer-grid {
    display: grid;
    grid-template-columns: 1.5fr 1fr 1fr 1.5fr;
    gap: 40px;
    padding-bottom: 40px;
}
.footer-logo {
    font-size: 24px;
    font-weight: 800;
    color: var(--white);
    margin-bottom: 16px;
    letter-spacing: 1px;
}
.footer-col p {
    font-size: 14px;
    line-height: 1.8;
    margin-bottom: 12px;
}
.footer-col h4 {
    color: var(--white);
    font-size: 16px;
    font-weight: 700;
    margin-bottom: 20px;
    padding-bottom: 10px;
    border-bottom: 2px solid var(--primary-red);
    display: inline-block;
}
.footer-links li { margin-bottom: 10px; }
.footer-links a {
    font-size: 14px;
    color: rgba(255,255,255,0.65);
    transition: var(--transition);
}
.footer-links a:hover {
    color: var(--white);
    padding-left: 6px;
}
.footer-contact p {
    font-size: 14px;
    line-height: 1.8;
    margin-bottom: 10px;
}
.footer-bottom {
    background: var(--primary-red-dark);
    padding: 18px 0;
    font-size: 13px;
    color: rgba(255,255,255,0.8);
}
.footer-bottom .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}
.footer-bottom a {
    color: rgba(255,255,255,0.8);
    margin-left: 16px;
}
.footer-bottom a:hover { color: var(--white); }

/* ===== 返回顶部 ===== */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 48px;
    height: 48px;
    background: var(--primary-red);
    color: var(--white);
    border: none;
    border-radius: 50%;
    font-size: 20px;
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transition: var(--transition);
    z-index: 999;
    box-shadow: var(--shadow-md);
}
.back-to-top.show {
    opacity: 1;
    visibility: visible;
}
.back-to-top:hover {
    background: var(--primary-red-dark);
    transform: translateY(-4px);
}

/* ===== 动画 ===== */
@keyframes fadeInUp {
    from { opacity: 0; transform: translateY(30px); }
    to { opacity: 1; transform: translateY(0); }
}
@keyframes bounce {
    0%, 20%, 50%, 80%, 100% { transform: translateX(-50%) translateY(0); }
    40% { transform: translateX(-50%) translateY(-10px); }
    60% { transform: translateX(-50%) translateY(-5px); }
}
@keyframes scrollDot {
    0% { opacity: 1; top: 8px; }
    100% { opacity: 0; top: 20px; }
}
.fade-in {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.8s ease, transform 0.8s ease;
}
.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ===== Toast ===== */
.toast {
    position: fixed;
    top: 100px;
    left: 50%;
    transform: translateX(-50%) translateY(-20px);
    background: var(--dark-gray);
    color: var(--white);
    padding: 14px 28px;
    border-radius: 4px;
    font-size: 14px;
    opacity: 0;
    visibility: hidden;
    transition: var(--transition);
    z-index: 9999;
    box-shadow: var(--shadow-lg);
}
.toast.show {
    opacity: 1;
    visibility: visible;
    transform: translateX(-50%) translateY(0);
}

/* ===== 响应式 ===== */
@media (max-width: 992px) {
    .nav-menu { display: none; }
    .nav-menu.open {
        display: flex;
        flex-direction: column;
        position: absolute;
        top: 72px;
        left: 0; right: 0;
        background: var(--white);
        box-shadow: var(--shadow-md);
        padding: 10px 0;
    }
    .nav-menu.open > li > a { padding: 14px 24px; }
    .nav-menu.open > li.has-dropdown > a::after { float: right; }
    /* 移动端下拉默认展开 */
    .nav-menu.open .dropdown {
        position: static;
        opacity: 1;
        visibility: visible;
        transform: none;
        box-shadow: none;
        border-top: none;
        border-radius: 0;
        background: rgba(0,0,0,0.03);
        min-width: 0;
        padding: 0;
        max-height: 0;
        overflow: hidden;
        transition: max-height .3s ease;
    }
    .nav-menu.open .dropdown.expanded {
        max-height: 500px;
        padding: 4px 0;
    }
    .nav-menu.open .dropdown li a {
        padding: 11px 36px;
        font-size: 13px;
        border-left: 3px solid transparent;
    }
    .mobile-toggle { display: flex; }
    .hero h1 { font-size: 32px; }
    .hero p { font-size: 15px; }
    .stats-grid { grid-template-columns: 1fr; gap: 20px; }
    .industry-detail { grid-template-columns: 1fr; gap: 30px; }
    .expertise-grid { grid-template-columns: 1fr; gap: 30px; }
    .service-grid { grid-template-columns: repeat(2, 1fr); }
    .product-grid { grid-template-columns: 1fr; }
    .global-regions { grid-template-columns: repeat(2, 1fr); }
    .contact-grid { grid-template-columns: 1fr; }
    .footer-grid { grid-template-columns: repeat(2, 1fr); }
    .hero-bg, .page-hero-bg { background-attachment: scroll; }
}

@media (max-width: 576px) {
    .top-bar-left span { display: block; margin-bottom: 4px; }
    .hero { min-height: 480px; }
    .hero h1 { font-size: 26px; }
    .page-hero h1 { font-size: 28px; }
    .section-title { font-size: 24px; }
    .service-grid { grid-template-columns: 1fr; }
    .global-regions { grid-template-columns: 1fr; }
    .footer-grid { grid-template-columns: 1fr; }
    .form-row { grid-template-columns: 1fr; }
    .footer-bottom .container { flex-direction: column; gap: 8px; text-align: center; }
    .stat-number { font-size: 36px; }
    .content-section { padding: 50px 0; }
}