/* ========================================
   山东亿盟进出口有限公司 - 主样式表
   重型机械海外贸易 | 工业风格
   ======================================== */

/* 全局重置 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary: #c7460a;
    --primary-dark: #9c3608;
    --primary-light: #f97316;
    --dark: #1a1a2e;
    --dark2: #16213e;
    --gray: #6b7280;
    --gray-light: #9ca3af;
    --light: #f5f5f5;
    --light2: #fafafa;
    --white: #ffffff;
    --border: #e5e7eb;
    --shadow: 0 4px 24px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 12px 48px rgba(0, 0, 0, 0.12);
    --radius: 8px;
    --transition: 0.3s ease;
}

html {
    scroll-behavior: smooth;
}

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

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

a {
    text-decoration: none;
    color: inherit;
}

ul {
    list-style: none;
}

img {
    max-width: 100%;
    display: block;
}

/* ========================================
   导航栏 - 居中悬浮
   ======================================== */
.header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    transition: transform 0.3s;
}

.header-top {
    background: var(--dark);
    padding: 8px 0;
    font-size: 13px;
    color: #cbd5e1;
}

.header-top-inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.header-contact {
    display: flex;
    gap: 24px;
}

/* 语言切换 */
.lang-switcher {
    display: flex;
    align-items: center;
    gap: 8px;
}

.lang-btn {
    background: none;
    border: none;
    color: #cbd5e1;
    font-size: 13px;
    cursor: pointer;
    padding: 2px 6px;
    transition: color 0.3s;
    font-family: inherit;
}

.lang-btn:hover {
    color: var(--white);
}

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

.lang-divider {
    color: #4b5563;
}

/* 主导航 */
.header-main {
    background: rgba(26, 26, 46, 0.92);
    border-bottom: 1px solid rgba(255, 255, 255, 0.06);
    transition: background 0.3s, box-shadow 0.3s;
}

.header.scrolled .header-main {
    background: rgba(26, 26, 46, 0.97);
    box-shadow: 0 4px 32px rgba(0, 0, 0, 0.3);
}

.header-main-inner {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 72px;
    position: relative;
}

/* Logo */
.logo {
    position: absolute;
    left: 24px;
    display: flex;
    align-items: center;
    gap: 10px;
    color: var(--white);
    text-decoration: none;
}

.logo-icon {
    font-size: 32px;
    color: var(--primary-light);
    animation: gearSpin 8s linear infinite;
}

@keyframes gearSpin {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

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

.logo-cn {
    font-size: 18px;
    font-weight: 700;
    letter-spacing: 2px;
}

.logo-en {
    font-size: 11px;
    font-weight: 500;
    color: var(--primary-light);
    letter-spacing: 3px;
}

/* 导航菜单 - 居中 */
.nav {
    display: flex;
    justify-content: center;
}

.nav-list {
    display: flex;
    gap: 40px;
}

.nav-link {
    font-size: 15px;
    font-weight: 500;
    color: #cbd5e1;
    transition: color 0.4s;
    position: relative;
    padding: 8px 16px;
    border-radius: 6px;
    z-index: 1;
}

.nav-link::before {
    content: '';
    position: absolute;
    inset: 0;
    border-radius: 6px;
    background: linear-gradient(
        135deg,
        rgba(199, 70, 10, 0.9),
        rgba(249, 115, 22, 0.7),
        rgba(199, 70, 10, 0.9)
    );
    background-size: 200% 200%;
    opacity: 0;
    z-index: -1;
    transition: opacity 0.4s ease;
    animation: liquidShimmer 3s ease-in-out infinite;
    filter: blur(0px);
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 0;
    height: 3px;
    border-radius: 3px;
    background: linear-gradient(
        90deg,
        transparent,
        var(--primary-light),
        #fbbf24,
        var(--primary-light),
        transparent
    );
    background-size: 200% 100%;
    transition: width 0.4s cubic-bezier(0.25, 0.8, 0.25, 1.2);
    box-shadow: 0 0 12px rgba(249, 115, 22, 0.6),
                0 0 24px rgba(249, 115, 22, 0.3);
    animation: liquidGlow 2s ease-in-out infinite;
}

@keyframes liquidShimmer {
    0%, 100% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
}

@keyframes liquidGlow {
    0%, 100% { filter: brightness(1); }
    50% { filter: brightness(1.5); }
}

.nav-link:hover,
.nav-link.active {
    color: var(--white);
}

.nav-link:hover::before,
.nav-link.active::before {
    opacity: 1;
}

.nav-link:hover::after,
.nav-link.active::after {
    width: 100%;
}

/* 汉堡菜单按钮 */
.hamburger {
    display: none;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    gap: 5px;
    width: 40px;
    height: 40px;
    background: none;
    border: none;
    cursor: pointer;
    z-index: 1100;
    padding: 4px;
    position: absolute;
    right: 24px;
}

.hamburger span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--white);
    border-radius: 2px;
    transition: all 0.3s;
}

.hamburger.active span:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
}

.hamburger.active span:nth-child(2) {
    opacity: 0;
}

.hamburger.active span:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
}

/* ========================================
   轮播图
   ======================================== */
.carousel {
    position: relative;
    width: 100%;
    height: 100vh;
    min-height: 600px;
    overflow: hidden;
    will-change: transform;
}

.carousel-track {
    width: 100%;
    height: 100%;
    position: relative;
}

.carousel-slide {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    opacity: 0;
    transition: opacity 0.8s ease;
    pointer-events: none;
}

.carousel-slide.active {
    opacity: 1;
    pointer-events: auto;
}

.carousel-bg {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    transform: translateZ(0);
    will-change: opacity;
}

.carousel-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(
        135deg,
        rgba(26, 26, 46, 0.85) 0%,
        rgba(26, 26, 46, 0.55) 50%,
        rgba(26, 26, 46, 0.35) 100%
    );
}

.carousel-content {
    position: relative;
    z-index: 2;
    max-width: 800px;
    padding: 0 40px;
    top: 50%;
    transform: translateY(-50%);
    margin: 0 auto;
    text-align: center;
}

.carousel-tag {
    display: inline-block;
    padding: 6px 20px;
    background: var(--primary);
    color: var(--white);
    font-size: 13px;
    font-weight: 600;
    letter-spacing: 4px;
    border-radius: 2px;
    margin-bottom: 24px;
    text-transform: uppercase;
}

.carousel-content h2 {
    font-size: 48px;
    font-weight: 800;
    color: var(--white);
    line-height: 1.25;
    margin-bottom: 20px;
    letter-spacing: 2px;
}

.carousel-content p {
    font-size: 18px;
    color: #cbd5e1;
    margin-bottom: 36px;
    max-width: 560px;
    margin-left: auto;
    margin-right: auto;
}

/* 轮播按钮 */
.carousel-btn {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    z-index: 10;
    width: 52px;
    height: 52px;
    border-radius: 50%;
    border: 2px solid rgba(255, 255, 255, 0.3);
    background: rgba(0, 0, 0, 0.3);
    color: var(--white);
    font-size: 20px;
    cursor: pointer;
    transition: all 0.3s;
    display: flex;
    align-items: center;
    justify-content: center;
    backdrop-filter: blur(4px);
}

.carousel-btn:hover {
    background: var(--primary);
    border-color: var(--primary);
}

.carousel-prev { left: 32px; }
.carousel-next { right: 32px; }

/* 轮播指示点 */
.carousel-dots {
    position: absolute;
    bottom: 40px;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    gap: 12px;
    z-index: 10;
}

.dot {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.4);
    cursor: pointer;
    transition: all 0.3s;
}

.dot.active {
    background: var(--primary-light);
    width: 32px;
    border-radius: 6px;
}

/* ========================================
   按钮
   ======================================== */
.btn {
    display: inline-block;
    padding: 14px 36px;
    border-radius: 4px;
    font-size: 15px;
    font-weight: 600;
    border: none;
    cursor: pointer;
    transition: all 0.3s;
    letter-spacing: 1px;
}

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

.btn-primary:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: 0 8px 28px rgba(199, 70, 10, 0.35);
}

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

.btn-outline:hover {
    background: var(--primary);
    color: var(--white);
    box-shadow: 0 8px 28px rgba(199, 70, 10, 0.25);
}

/* ========================================
   通用区域
   ======================================== */
.section {
    padding: 100px 0;
    content-visibility: auto;
    contain-intrinsic-size: auto 500px;
}

.section-label {
    text-align: center;
    font-size: 13px;
    font-weight: 700;
    color: var(--primary);
    letter-spacing: 4px;
    text-transform: uppercase;
    margin-bottom: 12px;
}

.section-title {
    text-align: center;
    font-size: 36px;
    font-weight: 800;
    margin-bottom: 16px;
    color: var(--dark);
    letter-spacing: 1px;
}

.section-desc {
    text-align: center;
    font-size: 17px;
    color: var(--gray);
    margin-bottom: 60px;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

/* ========================================
   关于我们
   ======================================== */
.about {
    background: var(--white);
}

.about-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 64px;
    align-items: center;
}

.about-image {
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: var(--shadow-lg);
}

.about-image img {
    width: 100%;
    height: 420px;
    object-fit: cover;
}

.about-text p {
    margin-bottom: 20px;
    font-size: 16px;
    color: var(--gray);
    line-height: 1.8;
}

.about-stats {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
    margin-top: 32px;
}

.stat-item {
    text-align: center;
    padding: 24px 16px;
    background: var(--light2);
    border-radius: var(--radius);
    border: 1px solid var(--border);
    transition: all 0.3s;
}

.stat-item:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow);
    border-color: var(--primary-light);
}

.stat-number {
    display: block;
    font-size: 36px;
    font-weight: 800;
    color: var(--primary);
    margin-bottom: 6px;
}

.stat-label {
    font-size: 14px;
    color: var(--gray);
    font-weight: 500;
}

/* ========================================
   产品中心 - 3D 翻转卡片
   ======================================== */
.products {
    background: var(--light);
}

.products-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
}

.product-card {
    perspective: 1200px;
    height: 440px;
}

.product-card-inner {
    position: relative;
    width: 100%;
    height: 100%;
    transition: transform 0.7s cubic-bezier(0.4, 0, 0.2, 1);
    transform-style: preserve-3d;
}

.product-card:hover .product-card-inner {
    transform: rotateY(180deg);
}

@media (hover: none) {
    .product-card:active .product-card-inner {
        transform: rotateY(180deg);
    }
}

.product-card-front,
.product-card-back {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
    -webkit-backface-visibility: hidden;
    border-radius: var(--radius);
    overflow: hidden;
    border: 1px solid var(--border);
    background: var(--white);
}

.product-card-front {
    z-index: 2;
}

.product-card-back {
    transform: rotateY(180deg);
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(160deg, var(--dark), var(--dark2));
    border-color: rgba(255, 255, 255, 0.08);
}

.product-card-back-link {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    text-decoration: none;
    color: var(--white);
    padding: 32px 24px;
    text-align: center;
    width: 100%;
    height: 100%;
}

.product-card-back .product-card-cat {
    font-size: 12px;
    font-weight: 700;
    color: var(--primary-light);
    letter-spacing: 3px;
    text-transform: uppercase;
    margin-bottom: 12px;
}

.product-card-back h3 {
    font-size: 19px;
    font-weight: 700;
    color: var(--white);
    margin-bottom: 24px;
}

.product-card-specs {
    list-style: none;
    width: 100%;
    margin-bottom: 24px;
}

.product-card-specs li {
    display: flex;
    justify-content: space-between;
    padding: 8px 0;
    border-bottom: 1px solid rgba(255, 255, 255, 0.08);
    font-size: 13px;
    color: #94a3b8;
}

.product-card-specs li span {
    color: var(--primary-light);
    font-weight: 600;
}

.product-card-cta {
    display: inline-block;
    padding: 10px 28px;
    background: var(--primary);
    color: var(--white);
    border-radius: 4px;
    font-size: 14px;
    font-weight: 600;
    letter-spacing: 1px;
    transition: all 0.3s;
}

.product-card-cta:hover {
    background: var(--primary-dark);
    box-shadow: 0 6px 24px rgba(199, 70, 10, 0.5);
    transform: translateY(-2px);
}

/* 正面卡片样式 */
.product-card-img {
    height: 220px;
    overflow: hidden;
}

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

.product-card-body {
    padding: 20px;
}

.product-card-cat {
    font-size: 12px;
    font-weight: 700;
    color: var(--primary);
    letter-spacing: 2px;
    text-transform: uppercase;
}

.product-card-body h3 {
    font-size: 18px;
    font-weight: 700;
    color: var(--dark);
    margin: 8px 0;
}

.product-card-body p {
    font-size: 14px;
    color: var(--gray);
}

.products-more {
    text-align: center;
    margin-top: 48px;
}

/* ========================================
   核心优势
   ======================================== */
.advantage {
    background: var(--white);
}

.advantage-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 28px;
}

.advantage-card {
    padding: 36px 28px;
    border-radius: var(--radius);
    border: 1px solid var(--border);
    text-align: center;
    transition: all 0.3s;
    background: var(--white);
}

.advantage-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-light);
}

.advantage-icon {
    font-size: 48px;
    margin-bottom: 20px;
}

.advantage-card h3 {
    font-size: 18px;
    font-weight: 700;
    color: var(--dark);
    margin-bottom: 12px;
}

.advantage-card p {
    font-size: 14px;
    color: var(--gray);
    line-height: 1.7;
}

/* ========================================
   联系我们
   ======================================== */
.contact {
    background: var(--light);
}

.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 56px;
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.contact-item {
    display: flex;
    align-items: flex-start;
    gap: 16px;
}

.contact-item-icon {
    font-size: 22px;
    flex-shrink: 0;
    margin-top: 2px;
}

.contact-item strong {
    display: block;
    font-size: 15px;
    color: var(--dark);
    margin-bottom: 4px;
}

.contact-item p {
    font-size: 15px;
    color: var(--gray);
}

/* 表单 */
.contact-form {
    display: flex;
    flex-direction: column;
    gap: 18px;
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 18px;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 14px 18px;
    border: 1px solid var(--border);
    border-radius: 4px;
    font-size: 15px;
    font-family: inherit;
    transition: all 0.3s;
    outline: none;
    background: var(--white);
}

.form-group input:focus,
.form-group textarea:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(199, 70, 10, 0.08);
}

/* ========================================
   页脚
   ======================================== */
.footer {
    background: var(--dark);
    color: #cbd5e1;
    padding: 64px 0 0;
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1.5fr;
    gap: 48px;
    padding-bottom: 48px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.footer-logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 16px;
    font-weight: 700;
    color: var(--white);
    margin-bottom: 12px;
}

.footer-brand p {
    font-size: 14px;
    color: var(--gray-light);
}

.footer-links h4,
.footer-products h4,
.footer-contact h4 {
    font-size: 15px;
    font-weight: 700;
    color: var(--white);
    margin-bottom: 16px;
}

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

.footer-links ul li a,
.footer-products ul li a {
    font-size: 14px;
    color: var(--gray-light);
    transition: color 0.3s;
}

.footer-links ul li a:hover,
.footer-products ul li a:hover {
    color: var(--primary-light);
}

.footer-contact p {
    font-size: 14px;
    color: var(--gray-light);
    margin-bottom: 8px;
}

.footer-bottom {
    text-align: center;
    padding: 24px 0;
    font-size: 13px;
    color: var(--gray-light);
}

/* ========================================
   响应式 - 平板端 (768px ~ 1024px)
   ======================================== */
@media (max-width: 1024px) {
    .container {
        padding: 0 20px;
    }

    /* 导航 */
    .header-main-inner {
        height: 64px;
    }
    .logo-cn { font-size: 16px; }
    .logo-en { font-size: 10px; }
    .nav-list { gap: 28px; }
    .nav-link { font-size: 14px; }

    /* 轮播 */
    .carousel { min-height: 500px; }
    .carousel-content h2 { font-size: 38px; }
    .carousel-content p { font-size: 16px; }
    .carousel-tag { font-size: 12px; padding: 5px 16px; letter-spacing: 3px; }
    .carousel-btn { width: 44px; height: 44px; font-size: 18px; }
    .carousel-prev { left: 20px; }
    .carousel-next { right: 20px; }

    /* 通用 */
    .section { padding: 80px 0; }
    .section-title { font-size: 30px; }
    .section-desc { font-size: 16px; margin-bottom: 48px; }

    /* 关于我们 */
    .about-grid { gap: 40px; }
    .about-image img { height: 340px; }
    .about-text p { font-size: 15px; }
    .stat-number { font-size: 30px; }
    .stat-item { padding: 20px 12px; }

    /* 产品 */
    .products-grid { grid-template-columns: repeat(3, 1fr); gap: 20px; }
    .product-card { height: 380px; }
    .product-card-img { height: 170px; }

    /* 优势 */
    .advantage-grid { grid-template-columns: repeat(2, 1fr); gap: 20px; }
    .advantage-card { padding: 28px 20px; }

    /* 联系 */
    .contact-grid { gap: 40px; }

    /* 页脚 */
    .footer-grid { grid-template-columns: 1fr 1fr; gap: 36px; }
    .footer { padding: 48px 0 0; }
}

/* ========================================
   响应式 - 手机横屏 / 小平板 (480px ~ 768px)
   - 汉堡菜单激活
   - 两列变一列过渡
   ======================================== */
@media (max-width: 768px) {
    .container {
        padding: 0 16px;
    }

    /* ===== 页眉 ===== */
    .header-top { padding: 6px 0; font-size: 12px; }
    .header-contact { gap: 16px; font-size: 12px; }

    .header-main-inner {
        height: 60px;
        flex-direction: row;
        justify-content: space-between;
    }

    .logo { position: static; }
    .logo-icon { font-size: 26px; }
    .logo-cn { font-size: 15px; }
    .logo-en { font-size: 10px; }

    /* 汉堡菜单 */
    .hamburger { display: flex; }

    /* 导航菜单 - 默认隐藏，展开时全屏覆盖 */
    .nav {
        position: fixed;
        top: 0;
        right: -100%;
        width: 75%;
        max-width: 320px;
        height: 100vh;
        background: var(--dark);
        padding: 100px 32px 40px;
        transition: right 0.35s ease;
        z-index: 1050;
        box-shadow: -8px 0 40px rgba(0, 0, 0, 0.4);
    }

    .nav.open {
        right: 0;
    }

    .nav-list {
        flex-direction: column;
        gap: 8px;
    }

    .nav-link {
        display: block;
        font-size: 17px;
        padding: 14px 0;
        border-bottom: 1px solid rgba(255, 255, 255, 0.08);
        color: #cbd5e1;
    }

    .nav-link::after,
    .nav-link::before { display: none; }

    /* 移动端导航遮罩 */
    .nav-overlay {
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        height: 100%;
        background: rgba(0, 0, 0, 0.5);
        z-index: 1040;
        opacity: 0;
        pointer-events: none;
        transition: opacity 0.35s ease;
    }

    .nav-overlay.show {
        opacity: 1;
        pointer-events: auto;
    }

    /* ===== 轮播 ===== */
    .carousel {
        height: 75vh;
        min-height: 420px;
    }
    .carousel-content {
        max-width: 100%;
        padding: 0 28px;
    }
    .carousel-content h2 {
        font-size: 28px;
        letter-spacing: 1px;
    }
    .carousel-content p {
        font-size: 14px;
        max-width: 100%;
        margin-bottom: 28px;
    }
    .carousel-tag {
        font-size: 11px;
        padding: 4px 14px;
        letter-spacing: 2px;
        margin-bottom: 18px;
    }
    .carousel-btn {
        width: 36px;
        height: 36px;
        font-size: 15px;
    }
    .carousel-prev { left: 8px; }
    .carousel-next { right: 8px; }
    .carousel-dots { bottom: 28px; gap: 10px; }
    .dot { width: 10px; height: 10px; }
    .dot.active { width: 26px; }

    /* ===== 通用 ===== */
    .section { padding: 60px 0; }
    .section-label { font-size: 12px; letter-spacing: 3px; }
    .section-title { font-size: 26px; }
    .section-desc { font-size: 15px; margin-bottom: 36px; }

    /* ===== 关于我们 ===== */
    .about-grid {
        grid-template-columns: 1fr;
        gap: 32px;
    }
    .about-image img { height: 260px; }
    .about-text p { font-size: 15px; }
    .about-stats { gap: 14px; margin-top: 24px; }
    .stat-number { font-size: 28px; }
    .stat-label { font-size: 13px; }

    /* ===== 产品中心 ===== */
    .products-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 16px;
    }
    .product-card { height: 380px; }
    .product-card-img { height: 160px; }
    .product-card-body { padding: 14px; }
    .product-card-body h3 { font-size: 15px; }
    .product-card-body p { font-size: 12px; }
    .product-card-cat { font-size: 11px; }
    .product-card-back h3 { font-size: 16px; }
    .product-card-specs li { font-size: 12px; padding: 6px 0; }
    .product-card-cta { font-size: 12px; padding: 8px 20px; }
    .products-more { margin-top: 36px; }

    /* ===== 优势 ===== */
    .advantage-grid { grid-template-columns: 1fr 1fr; gap: 16px; }
    .advantage-card { padding: 24px 16px; }
    .advantage-icon { font-size: 38px; margin-bottom: 14px; }
    .advantage-card h3 { font-size: 16px; }
    .advantage-card p { font-size: 13px; }

    /* ===== 联系我们 ===== */
    .contact-grid {
        grid-template-columns: 1fr;
        gap: 32px;
    }
    .form-row { grid-template-columns: 1fr; gap: 14px; }
    .contact-item { gap: 12px; }
    .contact-item-icon { font-size: 20px; }

    /* ===== 页脚 ===== */
    .footer { padding: 40px 0 0; }
    .footer-grid {
        grid-template-columns: 1fr 1fr;
        gap: 28px;
        padding-bottom: 32px;
    }
    .footer-bottom { padding: 18px 0; font-size: 12px; }

    /* 按钮 */
    .btn { padding: 12px 28px; font-size: 14px; }
}

/* ========================================
   响应式 - 手机竖屏 (< 480px)
   - 全部单列
   ======================================== */
@media (max-width: 480px) {
    .container {
        padding: 0 14px;
    }

    /* 页眉 */
    .header-top {
        padding: 5px 0;
        font-size: 11px;
    }
    .header-top-inner { gap: 4px; }
    .header-contact { gap: 10px; font-size: 11px; }
    .lang-btn { font-size: 12px; }

    .header-main-inner { height: 54px; }
    .logo-icon { font-size: 24px; }
    .logo-cn { font-size: 14px; letter-spacing: 1px; }
    .logo-en { font-size: 9px; letter-spacing: 2px; }
    .hamburger { width: 36px; height: 36px; right: 14px; }
    .hamburger span { width: 20px; }

    /* 轮播 */
    .carousel {
        height: 70vh;
        min-height: 360px;
    }
    .carousel-content {
        padding: 0 20px;
    }
    .carousel-content h2 {
        font-size: 22px;
        line-height: 1.3;
    }
    .carousel-content p {
        font-size: 13px;
        margin-bottom: 24px;
    }
    .carousel-tag {
        font-size: 10px;
        padding: 3px 12px;
        letter-spacing: 2px;
        margin-bottom: 14px;
    }
    .carousel-btn {
        width: 32px;
        height: 32px;
        font-size: 13px;
        border-width: 1px;
    }
    .carousel-prev { left: 6px; }
    .carousel-next { right: 6px; }
    .carousel-dots { bottom: 20px; gap: 8px; }
    .dot { width: 8px; height: 8px; }
    .dot.active { width: 22px; border-radius: 4px; }

    /* 通用 */
    .section { padding: 48px 0; }
    .section-label { font-size: 11px; letter-spacing: 2px; margin-bottom: 8px; }
    .section-title { font-size: 22px; }
    .section-desc { font-size: 14px; margin-bottom: 28px; }

    /* 关于我们 */
    .about-grid { gap: 24px; }
    .about-image img { height: 220px; }
    .about-text p { font-size: 14px; margin-bottom: 14px; }
    .about-stats {
        grid-template-columns: 1fr 1fr;
        gap: 10px;
        margin-top: 20px;
    }
    .stat-item { padding: 18px 10px; }
    .stat-number { font-size: 26px; }

    /* 产品中心 */
    .products-grid {
        grid-template-columns: 1fr;
        gap: 14px;
        max-width: 360px;
        margin: 0 auto;
    }
    .product-card-img { height: 200px; }
    .product-card-link { font-size: 13px; }
    .products-more { margin-top: 28px; }

    /* 优势 */
    .advantage-grid {
        grid-template-columns: 1fr;
        gap: 14px;
    }
    .advantage-card { padding: 24px 18px; }

    /* 联系 */
    .contact-grid { gap: 24px; }
    .contact-info { gap: 18px; }
    .contact-item strong { font-size: 14px; }
    .contact-item p { font-size: 14px; }
    .form-group input,
    .form-group textarea { padding: 12px 14px; font-size: 14px; }

    /* 页脚 */
    .footer { padding: 32px 0 0; }
    .footer-grid {
        grid-template-columns: 1fr;
        gap: 24px;
        padding-bottom: 28px;
    }
    .footer-links h4,
    .footer-products h4,
    .footer-contact h4 { font-size: 14px; margin-bottom: 10px; }
    .footer-bottom { padding: 14px 0; font-size: 11px; }

    /* 按钮 */
    .btn { padding: 12px 24px; font-size: 14px; letter-spacing: 0; }
}