/* =====================================================================
   外贸B2B前台模板样式（纯手写CSS，无框架）
   主色调 #1a6ee0 ｜ 容器 1200px ｜ 响应式断点：1200 / 992 / 768 / 480
   ===================================================================== */

/* ---------- 变量与重置 ---------- */
:root {
    --primary: #1a6ee0;
    --primary-dark: #1259b8;
    --primary-darker: #0d3d78;
    --primary-light: #e8f1fc;
    --danger: #e03535;
    --danger-dark: #c1272d;
    --success: #16a34a;
    --text: #22272e;
    --text-light: #646b78;
    --border: #e5e9f0;
    --bg: #f6f8fb;
    --white: #fff;
    --radius: 8px;
    --shadow: 0 2px 12px rgba(18, 50, 90, 0.08);
    --shadow-hover: 0 8px 24px rgba(26, 110, 224, 0.16);
    --container: 1200px;
    --transition: all 0.25s ease;
}

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

html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    font-size: 15px;
    line-height: 1.65;
    color: var(--text);
    background: var(--white);
}

img { max-width: 100%; height: auto; display: block; border: 0; }

a { color: var(--primary); text-decoration: none; transition: color 0.2s ease; }
a:hover { color: var(--primary-dark); }

ul, ol { list-style: none; }

button, input, select, textarea { font-family: inherit; font-size: inherit; color: inherit; }

svg { width: 18px; height: 18px; fill: currentColor; flex-shrink: 0; }

.container { max-width: var(--container); margin: 0 auto; padding: 0 20px; }

/* ---------- 通用按钮 ---------- */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 10px 22px;
    border: 2px solid transparent;
    border-radius: 6px;
    font-size: 15px;
    font-weight: 600;
    line-height: 1.3;
    cursor: pointer;
    text-align: center;
    transition: var(--transition);
    white-space: nowrap;
}

.btn svg { width: 17px; height: 17px; }

.btn-primary { background: var(--primary); border-color: var(--primary); color: var(--white); }
.btn-primary:hover { background: var(--primary-dark); border-color: var(--primary-dark); color: var(--white); box-shadow: var(--shadow-hover); }

.btn-danger { background: var(--danger); border-color: var(--danger); color: var(--white); }
.btn-danger:hover { background: var(--danger-dark); border-color: var(--danger-dark); color: var(--white); box-shadow: 0 8px 24px rgba(224, 53, 53, 0.25); }

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

.btn-light { background: var(--white); border-color: var(--white); color: var(--primary-darker); }
.btn-light:hover { background: var(--primary-light); color: var(--primary-dark); }

.btn-outline-light { background: transparent; border-color: rgba(255, 255, 255, 0.8); color: var(--white); }
.btn-outline-light:hover { background: rgba(255, 255, 255, 0.15); border-color: var(--white); color: var(--white); }

.btn-lg { padding: 13px 34px; font-size: 16px; }
.btn-sm { padding: 7px 16px; font-size: 13px; }

.btn[disabled] { opacity: 0.6; cursor: not-allowed; }

/* ---------- 顶部联系条 ---------- */
.topbar { background: var(--primary-darker); color: rgba(255, 255, 255, 0.92); font-size: 13px; }

.topbar-inner { display: flex; align-items: center; justify-content: space-between; gap: 16px; min-height: 38px; }

.topbar-contact { display: flex; align-items: center; flex-wrap: wrap; gap: 22px; }

.topbar-contact a { display: inline-flex; align-items: center; gap: 6px; color: rgba(255, 255, 255, 0.92); }
.topbar-contact a:hover { color: var(--white); }
.topbar-contact svg { width: 15px; height: 15px; }

.topbar-slogan { color: rgba(255, 255, 255, 0.65); overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }

/* ---------- 主头部与导航 ---------- */
.site-header { background: var(--white); border-bottom: 1px solid var(--border); box-shadow: 0 1px 4px rgba(18, 50, 90, 0.06); position: sticky; top: 0; z-index: 100; }

.header-inner { display: flex; align-items: center; justify-content: space-between; gap: 24px; min-height: 72px; }

.logo { display: flex; align-items: center; min-width: 0; }
.logo img { max-height: 48px; width: auto; object-fit: contain; }
.logo-text { font-size: 22px; font-weight: 800; color: var(--primary-darker); letter-spacing: 0.2px; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }

.main-nav { margin-left: auto; }

.nav-list { display: flex; align-items: center; gap: 4px; }

.nav-list > li { position: relative; }

.nav-list > li > a {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    padding: 26px 14px;
    font-size: 15px;
    font-weight: 600;
    color: var(--text);
    border-bottom: 3px solid transparent;
    transition: var(--transition);
}
.nav-list > li > a:hover { color: var(--primary); border-bottom-color: var(--primary); }

.nav-list .caret { font-size: 11px; opacity: 0.6; }

/* 桌面下拉菜单（一级分类） */
.dropdown {
    position: absolute;
    top: 100%;
    left: 0;
    min-width: 220px;
    background: var(--white);
    border: 1px solid var(--border);
    border-top: 3px solid var(--primary);
    border-radius: 0 0 var(--radius) var(--radius);
    box-shadow: 0 12px 28px rgba(18, 50, 90, 0.14);
    opacity: 0;
    visibility: hidden;
    transform: translateY(8px);
    transition: var(--transition);
    z-index: 110;
}
.has-dropdown:hover .dropdown,
.has-dropdown:focus-within .dropdown { opacity: 1; visibility: visible; transform: translateY(0); }

.dropdown li + li { border-top: 1px solid var(--border); }
.dropdown a { display: block; padding: 11px 18px; font-size: 14px; color: var(--text); background: var(--white); transition: var(--transition); }
.dropdown a:hover { background: var(--primary-light); color: var(--primary); padding-left: 24px; }

.header-right { display: flex; align-items: center; gap: 14px; }

.lang-switch { display: flex; align-items: center; gap: 4px; }
.lang-switch a {
    padding: 4px 8px;
    font-size: 12px;
    font-weight: 700;
    color: var(--text-light);
    border-radius: 4px;
    transition: var(--transition);
}
.lang-switch a:hover { color: var(--primary); }
.lang-switch a.active { background: var(--primary); color: var(--white); }

.btn-quote { padding: 9px 20px; font-size: 14px; }

/* 移动端汉堡按钮 */
.nav-toggle { display: none; flex-direction: column; justify-content: center; gap: 5px; width: 42px; height: 42px; padding: 9px; background: transparent; border: 1px solid var(--border); border-radius: 6px; cursor: pointer; }
.nav-toggle span { display: block; height: 2px; width: 100%; background: var(--primary-darker); border-radius: 2px; transition: var(--transition); }
.nav-toggle.active span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle.active span:nth-child(2) { opacity: 0; }
.nav-toggle.active span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ---------- Hero 横幅 ---------- */
.hero {
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-darker) 100%);
    color: var(--white);
    padding: 84px 0;
    text-align: center;
}

.hero-inner { max-width: 860px; }

.hero-title { font-size: 40px; font-weight: 800; line-height: 1.25; margin-bottom: 18px; }

.hero-sub { font-size: 17px; line-height: 1.8; color: rgba(255, 255, 255, 0.88); margin-bottom: 34px; }

.hero-actions { display: flex; justify-content: center; flex-wrap: wrap; gap: 16px; }

/* ---------- 通用区块 ---------- */
.section { padding: 64px 0; }
.section-gray { background: var(--bg); }
.section-sm { padding: 28px 0 40px; }

.section-title { font-size: 30px; font-weight: 800; text-align: center; color: var(--text); margin-bottom: 8px; }
.section-title::after { content: ""; display: block; width: 52px; height: 4px; margin: 14px auto 0; background: var(--primary); border-radius: 2px; }
.section-title-left { text-align: left; }
.section-title-left::after { margin-left: 0; }

.section-sub { text-align: center; color: var(--text-light); margin-bottom: 40px; }

.section-more { text-align: center; margin-top: 36px; }

.block-title { font-size: 24px; font-weight: 700; margin-bottom: 18px; padding-left: 12px; border-left: 5px solid var(--primary); }

/* ---------- 分类卡片 ---------- */
.category-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 22px; }

.category-card {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
    padding: 30px 20px 24px;
    background: var(--white);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    text-align: center;
    transition: var(--transition);
}
.category-card:hover { border-color: var(--primary); box-shadow: var(--shadow-hover); transform: translateY(-4px); }

.category-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 64px;
    height: 64px;
    margin-bottom: 6px;
    background: var(--primary-light);
    border-radius: 50%;
    color: var(--primary);
    transition: var(--transition);
}
.category-icon svg { width: 30px; height: 30px; }
.category-card:hover .category-icon { background: var(--primary); color: var(--white); }

.category-name { font-size: 17px; font-weight: 700; color: var(--text); }

.category-count { font-size: 13px; color: var(--text-light); }

.category-more { font-size: 13px; font-weight: 600; color: var(--primary); margin-top: 6px; }

/* ---------- 产品网格与卡片（桌面5列） ---------- */
.product-grid { display: grid; grid-template-columns: repeat(5, minmax(0, 1fr)); gap: 20px; }
.product-grid-related { grid-template-columns: repeat(4, minmax(0, 1fr)); }

.product-card {
    display: flex;
    flex-direction: column;
    background: var(--white);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    overflow: hidden;
    transition: var(--transition);
}
.product-card:hover { border-color: rgba(26, 110, 224, 0.45); box-shadow: var(--shadow-hover); transform: translateY(-4px); }

.product-thumb { display: block; aspect-ratio: 1 / 1; overflow: hidden; background: var(--bg); }
.product-thumb img { width: 100%; height: 100%; object-fit: cover; transition: transform 0.35s ease; }
.product-card:hover .product-thumb img { transform: scale(1.05); }

/* 无图CSS占位框 */
.thumb-placeholder {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 100%;
    height: 100%;
    padding: 12px;
    background: linear-gradient(135deg, var(--primary-light) 0%, #dce9fa 100%);
    color: var(--primary-dark);
    font-size: 14px;
    font-weight: 700;
    text-align: center;
    word-break: break-word;
}
.thumb-placeholder span { max-height: 100%; overflow: hidden; display: -webkit-box; -webkit-line-clamp: 3; -webkit-box-orient: vertical; }

.product-body { display: flex; flex-direction: column; gap: 10px; padding: 14px 16px 18px; flex: 1; }

.product-name { font-size: 15px; font-weight: 600; line-height: 1.4; }
.product-name a { color: var(--text); display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden; }
.product-name a:hover { color: var(--primary); }

.product-meta { font-size: 13px; color: var(--text-light); display: flex; flex-direction: column; gap: 3px; }
.meta-label { color: var(--text-light); }
.meta-price { color: var(--danger); font-weight: 700; font-size: 14px; }

.product-body .btn { margin-top: auto; align-self: flex-start; }

/* ---------- 关于我们 ---------- */
.about-inner { display: grid; grid-template-columns: minmax(0, 7fr) minmax(0, 5fr); gap: 48px; align-items: center; }

.about-text p { color: var(--text-light); line-height: 1.9; margin: 18px 0 26px; }

.about-features { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.about-features li {
    padding: 20px 18px;
    background: var(--white);
    border: 1px solid var(--border);
    border-top: 3px solid var(--primary);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
}
.about-features strong { display: block; font-size: 15px; margin-bottom: 4px; color: var(--text); }
.about-features span { font-size: 13px; color: var(--text-light); }

/* ---------- 面包屑 ---------- */
.breadcrumb { display: flex; align-items: center; flex-wrap: wrap; gap: 8px; padding: 16px 0; font-size: 13px; color: var(--text-light); }
.breadcrumb a { color: var(--text-light); }
.breadcrumb a:hover { color: var(--primary); }
.breadcrumb-sep { color: #b6bec9; }
.breadcrumb-current { color: var(--text); font-weight: 600; }

/* ---------- 分类页头部 ---------- */
.category-header { padding: 8px 0 26px; border-bottom: 1px solid var(--border); margin-bottom: 30px; }
.page-title { font-size: 28px; font-weight: 800; margin-bottom: 8px; }
.category-desc { color: var(--text-light); max-width: 900px; }
.category-header .category-desc { margin-bottom: 0; }

.product-grid-list { margin-bottom: 12px; }

.empty-state { padding: 70px 20px; text-align: center; color: var(--text-light); }
.empty-state p { margin-bottom: 18px; font-size: 16px; }

/* ---------- 分页 ---------- */
.pagination { display: flex; justify-content: center; flex-wrap: wrap; gap: 8px; padding: 30px 0 10px; }

.page-link {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 40px;
    height: 40px;
    padding: 0 12px;
    background: var(--white);
    border: 1px solid var(--border);
    border-radius: 6px;
    font-size: 14px;
    font-weight: 600;
    color: var(--text);
    transition: var(--transition);
}
.page-link:hover { border-color: var(--primary); color: var(--primary); }
.page-link.current { background: var(--primary); border-color: var(--primary); color: var(--white); cursor: default; }

/* ---------- 产品详情 ---------- */
.product-layout { display: grid; grid-template-columns: minmax(0, 5fr) minmax(0, 7fr); gap: 40px; padding: 8px 0 20px; }

.gallery-main { border: 1px solid var(--border); border-radius: var(--radius); overflow: hidden; background: var(--bg); }
.gallery-main img { width: 100%; aspect-ratio: 1 / 1; object-fit: contain; }
.gallery-main .thumb-placeholder { aspect-ratio: 1 / 1; font-size: 20px; }

.gallery-thumbs { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 12px; }

.gallery-thumb {
    width: 72px;
    height: 72px;
    padding: 0;
    overflow: hidden;
    background: var(--white);
    border: 2px solid var(--border);
    border-radius: 6px;
    cursor: pointer;
    transition: var(--transition);
}
.gallery-thumb img { width: 100%; height: 100%; object-fit: cover; }
.gallery-thumb:hover { border-color: var(--primary-light); }
.gallery-thumb.active { border-color: var(--primary); }

.product-title { font-size: 26px; font-weight: 800; line-height: 1.35; margin-bottom: 18px; }

.product-attrs { border: 1px solid var(--border); border-radius: var(--radius); overflow: hidden; margin-bottom: 18px; }
.product-attrs li { display: flex; gap: 16px; padding: 11px 16px; font-size: 14px; }
.product-attrs li:nth-child(odd) { background: var(--bg); }
.attr-label { flex: 0 0 110px; color: var(--text-light); font-weight: 600; }
.attr-value { color: var(--text); }
.attr-price { color: var(--danger); font-weight: 700; font-size: 16px; }

.product-brief { color: var(--text-light); line-height: 1.85; margin-bottom: 22px; }

.product-cta { display: flex; flex-wrap: wrap; align-items: center; gap: 14px; margin-bottom: 22px; }

.product-video { margin-top: 6px; }
.product-video video { width: 100%; max-height: 420px; border-radius: var(--radius); background: #000; }

/* 规格表 */
.table-wrap { overflow-x: auto; -webkit-overflow-scrolling: touch; }

.spec-table { width: 100%; border-collapse: collapse; font-size: 14px; background: var(--white); }
.spec-table th, .spec-table td { padding: 11px 16px; border: 1px solid var(--border); text-align: left; vertical-align: top; }
.spec-table th { width: 220px; background: var(--primary-light); color: var(--primary-darker); font-weight: 700; white-space: nowrap; }

/* 富文本内容（后台编辑器输出） */
.rich-content { color: var(--text); line-height: 1.9; font-size: 15px; }
.rich-content h2 { font-size: 21px; font-weight: 700; margin: 26px 0 12px; color: var(--primary-darker); }
.rich-content h3 { font-size: 18px; font-weight: 700; margin: 20px 0 10px; }
.rich-content p { margin: 12px 0; }
.rich-content ul, .rich-content ol { margin: 12px 0 12px 22px; }
.rich-content ul li { list-style: disc; }
.rich-content ol li { list-style: decimal; }
.rich-content img { height: auto; margin: 14px 0; border-radius: 6px; }
.rich-content table { width: 100%; border-collapse: collapse; margin: 14px 0; }
.rich-content table th, .rich-content table td { padding: 8px 12px; border: 1px solid var(--border); }
.rich-content a { text-decoration: underline; }

/* ---------- 联系页 ---------- */
.contact-layout { display: grid; grid-template-columns: minmax(0, 5fr) minmax(0, 7fr); gap: 40px; padding: 8px 0 50px; }

.contact-content { margin-bottom: 20px; }

.contact-card { display: flex; flex-direction: column; gap: 4px; background: var(--bg); border: 1px solid var(--border); border-radius: var(--radius); padding: 8px 18px; }

.contact-item { display: flex; gap: 14px; padding: 15px 0; border-bottom: 1px dashed var(--border); }
.contact-item:last-child { border-bottom: 0; }
.contact-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background: var(--primary-light);
    color: var(--primary);
    border-radius: 8px;
}
.contact-item strong { display: block; font-size: 13px; color: var(--text-light); margin-bottom: 2px; }
.contact-item a, .contact-item span { font-size: 14px; color: var(--text); word-break: break-word; }
.contact-item a:hover { color: var(--primary); }

/* ---------- 询盘表单 ---------- */
.inquiry-section { background: var(--bg); border: 1px solid var(--border); border-radius: var(--radius); padding: 30px 32px 34px; }

.inquiry-tip { color: var(--text-light); margin-bottom: 22px; }

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

.form-field { margin-bottom: 18px; }

.form-field label { display: block; font-size: 14px; font-weight: 600; margin-bottom: 6px; }
.form-field label em { color: var(--danger); font-style: normal; }

.form-field input,
.form-field textarea {
    width: 100%;
    padding: 11px 14px;
    background: var(--white);
    border: 1px solid #cfd6e2;
    border-radius: 6px;
    font-size: 14px;
    transition: var(--transition);
}
.form-field input:focus,
.form-field textarea:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(26, 110, 224, 0.15);
}
.form-field textarea { resize: vertical; min-height: 110px; }

/* 蜜罐字段：对用户与爬虫隐藏，仅机器人会填写 */
.hp-field { position: absolute !important; left: -9999px !important; width: 1px; height: 1px; opacity: 0; pointer-events: none; }

.form-actions { display: flex; align-items: center; gap: 18px; flex-wrap: wrap; }

.recaptcha-note { font-size: 12px; color: var(--text-light); max-width: 480px; }
.recaptcha-note a { text-decoration: underline; }

.js-form-result { margin-top: 16px; font-size: 14px; line-height: 1.7; display: none; }
.js-form-result.form-success { display: block; padding: 12px 16px; background: #eaf7ef; border: 1px solid #bfe5cd; border-radius: 6px; color: var(--success); }
.js-form-result.form-error { display: block; padding: 12px 16px; background: #fdecec; border: 1px solid #f5c6c6; border-radius: 6px; color: var(--danger); }

/* ---------- 单页 ---------- */
.page-wrap { padding: 8px 0 50px; }
.page-wrap .rich-content { max-width: 960px; }

/* ---------- 404 ---------- */
.error-page { padding: 80px 20px 100px; text-align: center; }
.error-code {
    font-size: 120px;
    font-weight: 800;
    line-height: 1;
    background: linear-gradient(135deg, var(--primary), var(--primary-darker));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    color: var(--primary);
    margin-bottom: 10px;
}
.error-page h1 { font-size: 30px; margin-bottom: 10px; }
.error-desc { color: var(--text-light); margin-bottom: 28px; }
.error-actions { display: flex; justify-content: center; flex-wrap: wrap; gap: 14px; }

/* ---------- 页脚 ---------- */
.site-footer { background: var(--primary-darker); color: rgba(255, 255, 255, 0.78); margin-top: 50px; }

.footer-grid { display: grid; grid-template-columns: 2.2fr 1fr 1.2fr 1.6fr; gap: 36px; padding: 56px 20px 44px; }

.footer-logo img { max-height: 44px; width: auto; }
.footer-logo span { font-size: 20px; font-weight: 800; color: var(--white); }
.footer-intro { margin-top: 16px; font-size: 13.5px; line-height: 1.85; color: rgba(255, 255, 255, 0.65); }

.site-footer h4 { font-size: 16px; font-weight: 700; color: var(--white); margin-bottom: 18px; padding-bottom: 10px; border-bottom: 2px solid rgba(255, 255, 255, 0.15); }

.footer-links li + li { margin-top: 10px; }
.footer-links a { color: rgba(255, 255, 255, 0.78); font-size: 14px; transition: var(--transition); }
.footer-links a:hover { color: var(--white); padding-left: 4px; }

.footer-contact li { display: flex; align-items: flex-start; gap: 10px; font-size: 13.5px; }
.footer-contact li + li { margin-top: 12px; }
.footer-contact svg { width: 16px; height: 16px; margin-top: 3px; color: var(--primary); fill: currentColor; }
.footer-contact a { color: rgba(255, 255, 255, 0.78); word-break: break-word; }
.footer-contact a:hover { color: var(--white); }
.footer-contact span { word-break: break-word; }

.footer-social { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 20px; }
.footer-social a {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 6px;
    color: rgba(255, 255, 255, 0.85);
    transition: var(--transition);
}
.footer-social a:hover { background: var(--primary); color: var(--white); transform: translateY(-2px); }
.footer-social svg { width: 17px; height: 17px; }

.footer-bottom { border-top: 1px solid rgba(255, 255, 255, 0.12); padding: 18px 0; font-size: 13px; text-align: center; color: rgba(255, 255, 255, 0.55); }

/* ---------- 回到顶部 ---------- */
.back-to-top {
    position: fixed;
    right: 24px;
    bottom: 28px;
    z-index: 90;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 44px;
    height: 44px;
    background: var(--primary);
    color: var(--white);
    border-radius: 50%;
    box-shadow: 0 6px 18px rgba(26, 110, 224, 0.4);
    opacity: 0;
    visibility: hidden;
    transform: translateY(12px);
    transition: var(--transition);
}
.back-to-top.visible { opacity: 1; visibility: visible; transform: translateY(0); }
.back-to-top:hover { background: var(--primary-dark); color: var(--white); }
.back-to-top svg { width: 20px; height: 20px; }

/* =====================================================================
   响应式
   ===================================================================== */

/* ≤1200px：产品网格5列→4列 */
@media (max-width: 1200px) {
    .product-grid { grid-template-columns: repeat(4, minmax(0, 1fr)); }
}

/* ≤992px：移动导航 + 布局单列化 */
@media (max-width: 992px) {
    .nav-toggle { display: flex; }
    .btn-quote { display: none; }

    .main-nav {
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        margin-left: 0;
        background: var(--white);
        border-bottom: 1px solid var(--border);
        box-shadow: 0 16px 30px rgba(18, 50, 90, 0.14);
        max-height: 0;
        overflow: hidden;
        transition: max-height 0.3s ease;
    }
    .main-nav.nav-open { max-height: 80vh; overflow-y: auto; }

    .nav-list { flex-direction: column; align-items: stretch; gap: 0; padding: 8px 0; }
    .nav-list > li > a { display: block; padding: 13px 24px; border-bottom: 0; }
    .nav-list > li > a:hover { background: var(--primary-light); }

    /* 移动端下拉改为直接展开 */
    .dropdown { position: static; opacity: 1; visibility: visible; transform: none; box-shadow: none; border: 0; border-top: 1px dashed var(--border); border-radius: 0; min-width: 0; margin: 4px 0; }
    .dropdown a { padding-left: 44px; }
    .nav-list .caret { display: none; }

    .topbar-slogan { display: none; }

    .hero { padding: 60px 0; }
    .hero-title { font-size: 30px; }

    .category-grid { grid-template-columns: repeat(2, 1fr); gap: 16px; }

    .product-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }
    .product-grid-related { grid-template-columns: repeat(2, minmax(0, 1fr)); }

    .product-layout, .about-inner, .contact-layout { grid-template-columns: 1fr; gap: 28px; }
    .about-features { grid-template-columns: 1fr 1fr; gap: 12px; }

    .footer-grid { grid-template-columns: 1fr 1fr; gap: 30px; padding: 44px 20px 34px; }
}

/* ≤768px：产品网格3列→2列，表单单列 */
@media (max-width: 768px) {
    .section { padding: 44px 0; }
    .section-title { font-size: 24px; }

    .product-grid, .product-grid-related { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 14px; }

    .inquiry-form .form-row { grid-template-columns: 1fr; gap: 0; }

    .inquiry-section { padding: 22px 18px 26px; }
    .form-actions { flex-direction: column; align-items: stretch; }
    .form-actions .btn { width: 100%; }
    .recaptcha-note { max-width: 100%; }

    .page-title { font-size: 23px; }
    .product-title { font-size: 21px; }
    .spec-table th { width: 130px; }

    .hero-title { font-size: 25px; }
    .hero-actions .btn { width: 100%; max-width: 320px; }
}

/* ≤480px：页脚与顶栏收尾 */
@media (max-width: 480px) {
    .topbar-contact { gap: 12px; font-size: 12px; }
    .topbar-contact a:nth-child(3) { display: none; }

    .logo-text { font-size: 18px; }

    .category-grid { grid-template-columns: 1fr; }

    .footer-grid { grid-template-columns: 1fr; gap: 26px; }

    .back-to-top { right: 14px; bottom: 16px; width: 40px; height: 40px; }
}