/* =========================================================
   TANDA BIOTECH — STYLESHEET
   布局 / 样式 / 交互 完整实现
   ---------------------------------------------------------
   目录
   01. 设计变量 (Design Tokens)
   02. 基础重置 (Base)
   03. 按钮 (Buttons)
   04. 通用区块 (Sections & Utilities)
   05. 列表 (Feature / Problem List)
   06. 导航栏 (Navigation + Dropdown + Mobile)
   07. 首页 Hero (Split Layout)
   08. 对比表格 (Comparison Table)
   09. 首页产品区 (Product Blocks)
   10. 产品详情页 (Product Detail / Specs)
   11. 耗材区块 (System Integration)
   12. 关于页 (About / Founder / Backers)
   13. 技术页 (Technology)
   14. 联系页 (Contact + Form)
   15. 页脚 (CTA + Footer)
   16. 响应式 (Responsive)
   17. 无障碍与动效降级 (A11y / Reduced Motion)
   ========================================================= */

/* =========================================================
   01. 设计变量
   ========================================================= */

:root {
    --primary-blue: #469FE1;
    --secondary-blue: #5AADE8;
    --dark-blue: #2B7CB8;
    --navy: #0a2463;

    --text-dark: #1a1a1a;
    --text-gray: #5a5a5a;
    --text-muted: #94a3b8;

    --light-bg: #f8f9fa;
    --white: #ffffff;
    --blue-tint: #E8F4FC;

    --border-light: rgba(0, 0, 0, 0.05);
    --border-line: #e2e8f0;

    --shadow-sm: 0 2px 10px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 20px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 4px 20px rgba(0, 0, 0, 0.1);

    --radius-sm: 6px;
    --radius-md: 8px;
    --radius-lg: 12px;

    --nav-height: 70px;
    --container-max: 1400px;

    --ease: 0.3s ease;
}

/* =========================================================
   02. 基础重置
   ========================================================= */

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

html {
    scroll-behavior: smooth;
    /* 锚点定位时避开固定导航栏 */
    scroll-padding-top: calc(var(--nav-height) + 1rem);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen,
        Ubuntu, Cantarell, 'Helvetica Neue', 'PingFang SC', 'Microsoft YaHei', sans-serif;
    color: var(--text-dark);
    line-height: 1.6;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
}

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

a {
    color: inherit;
}

.container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 2rem;
}

/* 仅供屏幕阅读器 */
.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0 0 0 0);
    white-space: nowrap;
    border: 0;
}

/* 跳转到主内容 */
.skip-link {
    position: absolute;
    left: -9999px;
    top: 0;
    z-index: 1100;
    background: var(--primary-blue);
    color: #fff;
    padding: 0.75rem 1.25rem;
    border-radius: 0 0 var(--radius-md) 0;
    font-weight: 600;
    text-decoration: none;
}

.skip-link:focus {
    left: 0;
}

/* =========================================================
   03. 按钮
   ========================================================= */

.btn {
    padding: 1rem 2rem;
    border-radius: var(--radius-md);
    text-decoration: none;
    font-weight: 600;
    transition: all var(--ease);
    display: inline-block;
    font-size: 1rem;
    border: none;
    cursor: pointer;
    font-family: inherit;
    text-align: center;
}

.btn-primary {
    background: var(--primary-blue);
    color: #fff;
    box-shadow: 0 4px 15px rgba(30, 186, 247, 0.4);
}

.btn-primary:hover {
    background: var(--dark-blue);
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(30, 186, 247, 0.5);
}

/* 深色底上的次要按钮（Hero 区） */
.btn-secondary {
    border: 2px solid #fff;
    color: #fff;
    background: rgba(255, 255, 255, 0.15);
    -webkit-backdrop-filter: blur(4px);
    backdrop-filter: blur(4px);
}

.btn-secondary:hover {
    background: #fff;
    color: var(--dark-blue);
    transform: translateY(-2px);
}

.btn-outline {
    background: transparent;
    color: var(--primary-blue);
    border: 2px solid var(--primary-blue);
    padding: 0.75rem 1.5rem;
    font-weight: 600;
    border-radius: var(--radius-sm);
    text-decoration: none;
    transition: all 0.2s ease;
}

.btn-outline:hover {
    background: var(--primary-blue);
    color: #fff;
}

.btn-large {
    padding: 1.2rem 2.5rem;
    font-size: 1.1rem;
}

/* 浅色底上使用 .btn-secondary 时改为蓝色描边 */
.center-cta .btn-secondary,
.system-integration .btn-secondary,
.product-block-reverse .btn-secondary {
    border-color: var(--primary-blue);
    color: var(--primary-blue);
    background: transparent;
    -webkit-backdrop-filter: none;
    backdrop-filter: none;
}

.center-cta .btn-secondary:hover,
.system-integration .btn-secondary:hover,
.product-block-reverse .btn-secondary:hover {
    background: var(--primary-blue);
    color: #fff;
}

/* =========================================================
   04. 通用区块
   ========================================================= */

.section-header {
    text-align: center;
    max-width: 800px;
    margin: 0 auto 4rem;
}

.section-header h2 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    color: var(--text-dark);
}

.section-subhead {
    font-size: 1.1rem;
    color: var(--text-gray);
}

.section-intro {
    font-size: 1.1rem;
    color: var(--text-gray);
    max-width: 900px;
    margin: 0 auto 3rem;
    text-align: center;
}

.section-note {
    margin-top: 2rem;
    text-align: center;
    color: var(--text-gray);
}

.center-cta {
    text-align: center;
    margin-top: 3rem;
}

/* 固定导航下方占位（非首页） */
.page-spacer {
    height: var(--nav-height);
}

/* =========================================================
   05. 列表
   ========================================================= */

.feature-list {
    list-style: none;
    margin: 1.5rem 0;
}

.feature-list li {
    padding: 0.5rem 0 0.5rem 1.5rem;
    position: relative;
    color: var(--text-gray);
}

.feature-list li::before {
    content: "✓";
    position: absolute;
    left: 0;
    color: var(--primary-blue);
    font-weight: bold;
}

.problem-list {
    list-style: none;
    max-width: 800px;
    margin: 2rem 0;
}

.problem-list li {
    padding: 1rem 0 1rem 2rem;
    border-bottom: 1px solid rgba(0, 0, 0, 0.06);
    font-size: 1.05rem;
    line-height: 1.7;
    color: var(--text-gray);
    position: relative;
}

.problem-list li:last-child {
    border-bottom: none;
}

.problem-list li::before {
    content: "→";
    position: absolute;
    left: 0;
    color: var(--primary-blue);
    font-weight: 600;
}

.problem-list li strong {
    color: var(--text-dark);
}

/* =========================================================
   06. 导航栏
   ========================================================= */

.nav {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(255, 255, 255, 0.98);
    -webkit-backdrop-filter: blur(10px);
    backdrop-filter: blur(10px);
    z-index: 1000;
    border-bottom: 1px solid var(--border-light);
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
    transition: box-shadow var(--ease);
}

/* 页面滚动后加深阴影 */
.nav.is-scrolled {
    box-shadow: 0 4px 18px rgba(0, 0, 0, 0.1);
}

.nav-container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    display: flex;
    align-items: center;
    text-decoration: none;
}

.logo-img {
    height: 40px;
    width: auto;
}

.nav-links {
    display: flex;
    gap: 2.5rem;
    list-style: none;
    align-items: center;
}

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

.nav-links > li > a {
    text-decoration: none;
    color: var(--text-dark);
    font-size: 0.95rem;
    font-weight: 500;
    transition: color var(--ease);
    display: block;
    padding: 0.5rem 0;
}

.nav-links > li > a:hover {
    color: var(--primary-blue);
}

/* 当前页高亮 */
.nav-links > li > a.active:not(.nav-cta) {
    color: var(--primary-blue);
}

.nav-links > li > a.active:not(.nav-cta)::before {
    content: "";
    position: absolute;
    left: 0;
    right: 0;
    bottom: -2px;
    height: 2px;
    background: var(--primary-blue);
    border-radius: 2px;
}

/* --- 下拉菜单 --- */
.dropdown {
    position: relative;
}

.dropdown > a::after {
    content: '+';
    display: inline-block;
    margin-left: 0.4rem;
    font-size: 0.85em;
    font-weight: 600;
    transition: transform var(--ease);
}

.dropdown:hover > a::after,
.dropdown:focus-within > a::after,
.dropdown.is-open > a::after {
    transform: rotate(45deg);
}

.dropdown-menu {
    position: absolute;
    top: 100%;
    left: 0;
    background: #fff;
    min-width: 200px;
    box-shadow: var(--shadow-lg);
    border-radius: var(--radius-md);
    padding: 0.5rem 0;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    /* 显式声明各属性：关闭时先淡出再隐藏，避免 transition:all 对 visibility 的歧义 */
    transition: opacity 0.3s ease, transform 0.3s ease, visibility 0s linear 0.3s;
    margin-top: 0.5rem;
    list-style: none;
}

.dropdown:hover .dropdown-menu,
.dropdown:focus-within .dropdown-menu,
.dropdown.is-open .dropdown-menu {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
    transition: opacity 0.3s ease, transform 0.3s ease, visibility 0s linear 0s;
}

.dropdown-menu li {
    list-style: none;
}

.dropdown-menu a {
    display: block;
    padding: 0.75rem 1.5rem;
    color: var(--text-dark);
    text-decoration: none;
    font-size: 0.9rem;
    transition: all var(--ease);
}

.dropdown-menu a::after {
    display: none;
}

.dropdown-menu a:hover {
    background: var(--light-bg);
    color: var(--primary-blue);
}

/* --- 语言切换 --- */
/* 选择器需带 .nav-links > li.lang-switch，否则会被 .nav-links > li > a 压过 */
.nav-links > li.lang-switch {
    display: flex;
    align-items: center;
    gap: 0.25rem;
}

.nav-links > li.lang-switch > a {
    font-size: 0.85rem;
    color: var(--text-gray);
    padding: 0.25rem 0.5rem;
    border-radius: 4px;
    transition: all 0.2s;
}

.nav-links > li.lang-switch > a:hover {
    color: var(--primary-blue);
    background: var(--light-bg);
}

.nav-links > li.lang-switch > a.is-current {
    color: var(--primary-blue);
    font-weight: 600;
    background: var(--blue-tint);
}

/* --- 备案号 --- */
.footer-icp {
    color: var(--text-muted);
    font-size: 0.8rem;
    text-decoration: none;
    margin-left: 0.75rem;
}

.footer-icp:hover {
    color: var(--primary-blue);
}

/* --- 导航 CTA --- */
.nav-cta {
    background: var(--primary-blue);
    color: #fff !important;
    padding: 0.6rem 1.5rem !important;
    border-radius: var(--radius-sm);
    transition: background var(--ease);
    margin-left: 0.5rem;
}

.nav-cta:hover {
    background: var(--dark-blue);
    color: #fff !important;
}

/* --- 汉堡按钮 --- */
.mobile-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    cursor: pointer;
    background: none;
    border: none;
    padding: 0.5rem;
}

.mobile-toggle span {
    width: 25px;
    height: 3px;
    background: var(--text-dark);
    transition: var(--ease);
    display: block;
    border-radius: 2px;
}

/* 展开后变 X */
.mobile-toggle[aria-expanded="true"] span:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
}

.mobile-toggle[aria-expanded="true"] span:nth-child(2) {
    opacity: 0;
}

.mobile-toggle[aria-expanded="true"] span:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
}

/* =========================================================
   07. 首页 Hero
   ========================================================= */

.hero-split {
    margin-top: var(--nav-height);
    display: grid;
    grid-template-columns: 1fr 1fr;
    min-height: 500px;
}

.hero-split-content {
    display: flex;
    flex-direction: column;
    justify-content: center;
    padding: 3rem 4rem;
    background: var(--navy);
}

.hero-split-content h1 {
    font-size: 2.75rem;
    font-weight: 700;
    line-height: 1.15;
    margin-bottom: 1.25rem;
    color: #fff;
}

.hero-split-content .highlight {
    color: rgba(255, 255, 255, 0.85);
    display: block;
    margin-top: 0.25rem;
    font-size: 0.6em;
    font-weight: 400;
}

.hero-split-content .hero-subhead {
    font-size: 1.1rem;
    color: rgba(255, 255, 255, 0.9);
    margin-bottom: 1.5rem;
    line-height: 1.7;
}

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

.hero-split-image {
    background: #f5f5f5;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
}

.hero-split-image img {
    width: 100%;
    height: 100%;
    object-fit: contain;
    padding: 2rem;
}

/* 深蓝渐变变体 */
.hero-split.hero-dark {
    background: linear-gradient(135deg, var(--navy) 0%, var(--primary-blue) 90%);
}

.hero-split.hero-dark .hero-split-content,
.hero-split.hero-dark .hero-split-image {
    background: transparent;
}

.hero-split.hero-dark .hero-split-image img {
    filter: drop-shadow(0 10px 30px rgba(0, 0, 0, 0.3));
}

/* =========================================================
   08. 对比表格
   ========================================================= */

.comparison-home {
    padding: 5rem 0;
    background: var(--light-bg);
}

.comparison-table-wrapper {
    overflow-x: auto;
    margin: 2rem 0;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    -webkit-overflow-scrolling: touch;
}

.comparison-table {
    width: 100%;
    border-collapse: collapse;
    background: #fff;
    min-width: 600px;
}

.comparison-table th,
.comparison-table td {
    padding: 1rem 1.5rem;
    text-align: left;
    border-bottom: 1px solid #eee;
}

/* 表头用站点浅蓝底 + 深蓝字。深色字是为了对比度：
   白字压在品牌蓝 #469FE1 上只有 2.6:1，而表头是 16px 字号，不算大字。 */
.comparison-table thead th {
    background: var(--blue-tint);
    color: var(--navy);
    font-weight: 600;
    font-size: 1rem;
    border-bottom: 2px solid var(--primary-blue);
}

/* 高亮列（首页/技术页的自家产品列）用实底与浅色表头拉开层次，
   底色取更深的 --dark-blue 才够撑住白字 */
.comparison-table thead th.highlight-col {
    background: var(--dark-blue);
    color: #fff;
    border-bottom-color: var(--dark-blue);
}

.comparison-table tbody td {
    font-size: 0.95rem;
    color: var(--text-gray);
}

.comparison-table tbody td.highlight-col {
    background: rgba(30, 186, 247, 0.08);
    color: var(--text-dark);
}

.comparison-table th:first-child,
.comparison-table td:first-child,
.comparison-table th.highlight-col,
.comparison-table td.highlight-col {
    width: 35%;
}

.comparison-table tbody tr {
    transition: background 0.2s ease;
}

.comparison-table tbody tr:hover {
    background: var(--light-bg);
}

.comparison-table tbody tr:hover td.highlight-col {
    background: rgba(30, 186, 247, 0.15);
}

.comparison-table tbody tr:last-child td {
    border-bottom: none;
}

/* =========================================================
   09. 首页产品区
   ========================================================= */

.products-home {
    padding: 6rem 0;
}

.product-block,
.product-block-reverse {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
    margin-bottom: 5rem;
}

.product-block-reverse .product-content {
    order: 2;
}

.product-block-reverse .product-figure {
    order: 1;
}

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

.product-subtitle {
    color: var(--primary-blue);
    font-weight: 500;
    margin-bottom: 1rem;
}

.product-content p {
    color: var(--text-gray);
    margin-bottom: 1rem;
    line-height: 1.7;
}

.product-figure {
    display: flex;
    align-items: center;
    justify-content: center;
}

.product-figure img {
    max-width: 100%;
    height: auto;
}

.product-figure-img-large {
    max-width: 450px;
}

/* =========================================================
   10. 产品详情页
   ========================================================= */

.product-quick-nav {
    padding: 1.5rem 0;
    background: var(--light-bg);
    border-bottom: 1px solid var(--border-line);
}

.product-quick-nav .container {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

.product-detail {
    padding: 5rem 0;
    scroll-margin-top: var(--nav-height);
}

.product-detail-alt {
    background: var(--light-bg);
}

.product-detail-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: start;
}

.product-detail h2 {
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
    color: var(--text-dark);
}

.product-detail h3 {
    font-size: 1.5rem;
    margin-top: 2rem;
    margin-bottom: 1rem;
    color: var(--text-dark);
}

.product-detail p {
    color: var(--text-gray);
    line-height: 1.8;
    margin-bottom: 1rem;
}

.product-specs {
    font-size: 1.1rem;
    color: var(--primary-blue);
    margin: 1rem 0;
}

.price-explanation {
    font-size: 1rem;
}

.product-cta-group {
    margin-top: 2rem;
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

.product-cta-group .btn-secondary,
.product-cta-group .btn-outline {
    background: transparent;
    border: 2px solid var(--primary-blue);
    color: var(--primary-blue);
    -webkit-backdrop-filter: none;
    backdrop-filter: none;
}

.product-cta-group .btn-secondary:hover,
.product-cta-group .btn-outline:hover {
    background: var(--primary-blue);
    color: #fff;
}

.product-detail-image {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.product-img {
    width: 100%;
    max-width: 400px;
    height: auto;
}

.product-img-secondary {
    margin-top: 2rem;
}

.product-img-large {
    max-width: 500px;
}

.product-setup-figure {
    margin-top: 2.5rem;
    padding-top: 2rem;
    border-top: 1px solid var(--border-line);
}

.product-setup-figure img {
    max-width: 100%;
    border-radius: var(--radius-md);
}

.product-setup-figure figcaption {
    margin-top: 0.75rem;
    font-size: 0.9rem;
    color: var(--text-gray);
    text-align: center;
}

/* --- 规格表 --- */
.specs-table {
    width: 100%;
    margin: 1.5rem 0;
    border-collapse: collapse;
}

.specs-table tr {
    border-bottom: 1px solid #eee;
}

.specs-table tr:last-child {
    border-bottom: none;
}

.specs-table td {
    padding: 0.75rem 0;
}

.specs-table td:first-child {
    font-weight: 500;
    color: var(--text-dark);
    width: 40%;
}

.specs-table td:last-child {
    color: var(--text-gray);
}

/* --- 订货信息（多列表格，列数由后台内容决定） --- */
.ordering-tables {
    margin-top: 4rem;
    padding-top: 3rem;
    border-top: 1px solid var(--border-line);
}

.ordering-block {
    margin-bottom: 3rem;
}

.ordering-block:last-of-type {
    margin-bottom: 0;
}

.ordering-block h4 {
    font-size: 1.15rem;
    color: var(--text-dark);
    margin-bottom: 0.75rem;
}

.table-note {
    margin-top: 0.75rem;
    font-size: 0.9rem;
    color: var(--text-gray);
}

/* =========================================================
   11. 耗材区块
   ========================================================= */

.system-integration {
    padding: 6rem 0;
    background: var(--light-bg);
}

.system-integration h2 {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 1.5rem;
    color: var(--text-dark);
}

.system-benefits {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 2rem;
    margin: 3rem 0;
}

.benefit-item {
    background: #fff;
    padding: 2rem;
    border-radius: var(--radius-lg);
    text-align: center;
    box-shadow: var(--shadow-sm);
    transition: transform var(--ease), box-shadow var(--ease);
}

.benefit-item:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
}

.benefit-item h4 {
    color: var(--primary-blue);
    margin-bottom: 0.5rem;
}

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

/* =========================================================
   12. 关于页
   ========================================================= */

.about-section {
    padding: 2rem 0;
}

.about-section-alt {
    background: var(--light-bg);
}

/* 保持原站的隔行底色规则 */
.about-section:nth-of-type(even) {
    background: var(--light-bg);
}

.about-section h2 {
    font-size: 2.5rem;
    margin-bottom: 2rem;
    color: var(--text-dark);
}

.about-section h3 {
    font-size: 2rem;
    margin-bottom: 1.5rem;
    color: var(--text-dark);
}

.about-section p {
    font-size: 1.1rem;
    color: var(--text-gray);
    line-height: 1.8;
    margin-bottom: 1.5rem;
    max-width: 900px;
}

.about-section .mission-statement {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--primary-blue);
    line-height: 1.6;
    margin-bottom: 1.5rem;
    max-width: 800px;
}

/* --- 创始人卡片 --- */
.founder-profile {
    background: #fff;
    border-radius: var(--radius-md);
    padding: 2.5rem;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.06);
    margin-bottom: 2.5rem;
    max-width: 800px;
}

.founder-info h3 {
    font-size: 1.5rem;
    color: var(--text-dark);
    margin-bottom: 0.25rem;
}

.founder-title {
    font-size: 1.1rem;
    color: var(--primary-blue);
    font-weight: 500;
    margin-bottom: 1.5rem !important;
}

.founder-info p {
    margin-bottom: 1rem;
}

.founder-info p:last-child {
    margin-bottom: 0;
}

/* --- 团队说明 --- */
.team-note {
    max-width: 800px;
}

.team-note h4 {
    font-size: 1.25rem;
    color: var(--text-dark);
    margin-bottom: 1rem;
}

.team-note p {
    color: var(--text-gray);
    line-height: 1.8;
}

/* --- 支持机构 Logo --- */
.backed-intro {
    text-align: left;
    font-size: 2rem;
    font-weight: 900;
    color: var(--text-gray);
    margin-bottom: 3rem;
}

.backer-logos {
    display: flex;
    justify-content: center;
    align-items: center;
    flex-wrap: wrap;
    gap: 3rem 4rem;
    max-width: 900px;
    margin: 0 auto;
}

.backer-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

.backer-item img {
    height: 50px;
    width: auto;
    object-fit: contain;
}

.backer-label {
    font-size: 0.85rem;
    color: var(--text-gray);
    font-weight: 500;
}

.backer-dark-bg {
    background: #122847;
    padding: 1rem 1.5rem;
    border-radius: var(--radius-md);
}

/* =========================================================
   13. 技术页
   ========================================================= */

.section-compact {
    padding: 2rem 0 !important;
}

.section-compact h2 {
    margin-bottom: 1rem !important;
}

/* =========================================================
   14. 联系页
   ========================================================= */

.contact-section {
    padding: 4rem 0;
}

.contact-section > .container > h2 {
    font-size: 2.5rem;
    margin-bottom: 2rem;
    color: var(--text-dark);
}

.contact-grid {
    display: grid;
    grid-template-columns: 1.5fr 1fr;
    gap: 4rem;
    align-items: start;
}

.contact-form-wrapper {
    background: #fff;
    padding: 2.5rem;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.contact-info-card {
    background: #fff;
    padding: 1.5rem;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
}

.contact-info-card h3 {
    font-size: 1.1rem;
    color: var(--text-dark);
    margin-bottom: 1rem;
    padding-bottom: 0.75rem;
    border-bottom: 2px solid var(--primary-blue);
}

.contact-item {
    display: flex;
    gap: 1rem;
    margin-bottom: 1rem;
}

.contact-item:last-child {
    margin-bottom: 0;
}

.contact-item strong {
    display: block;
    font-size: 0.85rem;
    color: var(--text-gray);
    margin-bottom: 0.25rem;
}

.contact-item p {
    margin: 0;
    color: var(--text-dark);
}

.contact-item a {
    color: var(--primary-blue);
    text-decoration: none;
}

.contact-item a:hover {
    text-decoration: underline;
}

.trust-card {
    background: linear-gradient(135deg, rgba(30, 186, 247, 0.08), rgba(71, 159, 222, 0.05));
    border-left: none;
}

.trust-card p {
    font-size: 0.9rem;
    color: var(--text-gray);
    margin-bottom: 0.5rem;
    padding-left: 1rem;
    position: relative;
}

.trust-card p:last-child {
    margin-bottom: 0;
}

.trust-card p::before {
    content: "✓";
    position: absolute;
    left: 0;
    color: var(--primary-blue);
    font-weight: bold;
    font-size: 0.8rem;
}

/* --- 表单 --- */
.form-intro {
    color: var(--text-gray);
    margin-bottom: 1.75rem;
    font-size: 0.95rem;
}

.tanda-form {
    display: flex;
    flex-direction: column;
    gap: 1.25rem;
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.25rem;
}

.form-group {
    display: flex;
    flex-direction: column;
}

.form-group label {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-dark);
    margin-bottom: 0.5rem;
}

.form-group .required {
    color: #e53e3e;
}

.form-group input,
.form-group select,
.form-group textarea {
    padding: 0.875rem 1rem;
    border: 2px solid var(--border-line);
    border-radius: var(--radius-md);
    font-size: 1rem;
    font-family: inherit;
    color: var(--text-dark);
    background: #fff;
    transition: border-color var(--ease), box-shadow var(--ease);
    width: 100%;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-blue);
    box-shadow: 0 0 0 3px rgba(70, 159, 225, 0.15);
}

.form-group input::placeholder,
.form-group textarea::placeholder {
    color: #a0aec0;
}

.form-group select {
    cursor: pointer;
    appearance: none;
    -webkit-appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%235a5a5a' d='M6 8L1 3h10z'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 1rem center;
    padding-right: 2.5rem;
}

.form-group textarea {
    resize: vertical;
    min-height: 100px;
}

.tanda-form .btn {
    align-self: flex-start;
    margin-top: 0.5rem;
}

/* 校验错误态 */
.form-group.has-error input,
.form-group.has-error select,
.form-group.has-error textarea {
    border-color: #e53e3e;
}

.form-error {
    color: #e53e3e;
    font-size: 0.85rem;
    margin-top: 0.4rem;
    min-height: 1rem;
}

.form-consent {
    font-size: 0.8rem;
    color: var(--text-muted);
    line-height: 1.6;
}

/* 蜜罐字段：移出视口而非 display:none —— 部分机器人会跳过 display:none 的字段 */
.hp-field {
    position: absolute;
    left: -9999px;
    top: auto;
    width: 1px;
    height: 1px;
    overflow: hidden;
}

/* 提交成功提示 */
.form-success {
    display: none;
    background: rgba(70, 159, 225, 0.08);
    border: 1px solid rgba(70, 159, 225, 0.35);
    border-radius: var(--radius-md);
    padding: 1.25rem 1.5rem;
    color: var(--text-dark);
    margin-bottom: 1.5rem;
}

.form-success.is-visible {
    display: block;
}

.form-success strong {
    display: block;
    color: var(--primary-blue);
    margin-bottom: 0.25rem;
}

/* =========================================================
   15. 页脚
   ========================================================= */

.subtle-cta {
    background: #f8fafc;
    padding: 1.5rem 0;
    text-align: center;
    border-top: 1px solid var(--border-line);
}

.subtle-cta p {
    margin: 0;
    color: var(--text-gray);
    font-size: 0.95rem;
}

.subtle-cta a {
    color: var(--primary-blue);
    font-weight: 500;
    text-decoration: none;
}

.subtle-cta a:hover {
    text-decoration: underline;
}

.footer-compact {
    background: #f1f5f9;
    border-top: 1px solid var(--border-line);
    padding: 1.25rem 0 1rem;
}

.footer-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 1rem;
}

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

.footer-logo-small {
    height: 28px;
    width: auto;
}

.footer-tagline {
    color: var(--text-gray);
    font-size: 0.85rem;
    font-weight: 500;
    padding-left: 0.75rem;
    border-left: 1px solid #cbd5e1;
}

.footer-links {
    display: flex;
    gap: 1.5rem;
}

.footer-links a {
    color: var(--text-gray);
    text-decoration: none;
    font-size: 0.85rem;
    font-weight: 500;
    transition: color 0.2s;
}

.footer-links a:hover {
    color: var(--primary-blue);
}

.footer-contact-row {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.85rem;
    color: var(--text-gray);
}

.footer-contact-row a {
    color: var(--text-gray);
    text-decoration: none;
    transition: color 0.2s;
}

.footer-contact-row a:hover {
    color: var(--primary-blue);
}

.footer-divider {
    color: #cbd5e1;
}

.footer-social-link {
    display: flex;
    align-items: center;
}

.footer-social-link svg {
    fill: var(--text-gray);
    transition: fill 0.2s;
}

.footer-social-link:hover svg {
    fill: var(--primary-blue);
}

.footer-legal {
    text-align: center;
    padding-top: 0.75rem;
    margin-top: 0.75rem;
    border-top: 1px solid var(--border-line);
}

.footer-legal span {
    color: var(--text-muted);
    font-size: 0.8rem;
}

/* 返回顶部 */
.back-to-top {
    position: fixed;
    right: 1.5rem;
    bottom: 1.5rem;
    width: 44px;
    height: 44px;
    border-radius: 50%;
    border: none;
    background: var(--primary-blue);
    color: #fff;
    font-size: 1.1rem;
    line-height: 1;
    cursor: pointer;
    box-shadow: 0 4px 15px rgba(30, 186, 247, 0.4);
    opacity: 0;
    visibility: hidden;
    transform: translateY(10px);
    transition: all var(--ease);
    z-index: 900;
}

.back-to-top.is-visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.back-to-top:hover {
    background: var(--dark-blue);
}

/* =========================================================
   16. 响应式
   ========================================================= */

@media (max-width: 1024px) {
    .hero-split {
        grid-template-columns: 1fr;
        min-height: auto;
    }

    .hero-split-content {
        padding: 3rem 2rem;
        text-align: center;
    }

    .hero-split-content h1 {
        font-size: 2.5rem;
    }

    .hero-split-content .highlight {
        display: inline;
    }

    .hero-split-content .hero-buttons {
        justify-content: center;
    }

    .hero-split-image {
        order: -1;
        min-height: 300px;
    }

    .hero-split-image img {
        padding: 1.5rem;
    }

    .system-benefits {
        grid-template-columns: repeat(2, 1fr);
    }
}

/* --- 移动端导航（900px）---
   独立断点：导航有 5 项 + CTA，约需 900px；
   部分安卓设备视口大于 768px 但仍需汉堡菜单。 */
@media (max-width: 900px) {
    .mobile-toggle {
        display: flex;
    }

    .nav-links {
        position: fixed;
        top: var(--nav-height);
        left: -100%;
        width: 100%;
        height: calc(100vh - var(--nav-height));
        background: #fff;
        flex-direction: column;
        justify-content: flex-start;
        padding: 2rem;
        transition: left var(--ease);
        box-shadow: var(--shadow-lg);
        align-items: flex-start;
        overflow-y: auto;
        gap: 1rem;
    }

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

    .nav-links > li {
        width: 100%;
    }

    .nav-cta {
        margin-left: 0;
        margin-top: 1rem;
        display: inline-block;
    }

    /* 移动端下拉直接展开 */
    .dropdown-menu {
        position: static;
        opacity: 1;
        visibility: visible;
        transform: none;
        box-shadow: none;
        background: var(--light-bg);
        margin-top: 0.5rem;
        margin-bottom: 0.5rem;
        padding: 0.5rem 0;
        border-radius: var(--radius-md);
        min-width: 0;
        width: 100%;
    }

    .nav-links > li > a.active:not(.nav-cta)::before {
        display: none;
    }
}

@media (max-width: 768px) {
    .product-block,
    .product-block-reverse {
        grid-template-columns: 1fr;
        gap: 2rem;
    }

    .product-block .product-content,
    .product-block-reverse .product-content {
        order: 1;
    }

    .product-block .product-figure,
    .product-block-reverse .product-figure {
        order: 2;
    }

    .product-detail-grid {
        grid-template-columns: 1fr;
        gap: 2rem;
    }

    .system-benefits {
        grid-template-columns: 1fr;
    }

    .footer-row {
        flex-direction: column;
        text-align: center;
        gap: 1rem;
    }

    .footer-brand {
        flex-direction: column;
        gap: 0.5rem;
    }

    .footer-tagline {
        border-left: none;
        padding-left: 0;
    }

    .footer-links {
        flex-wrap: wrap;
        justify-content: center;
        gap: 1rem;
    }

    .footer-contact-row {
        flex-wrap: wrap;
        justify-content: center;
    }

    .section-header h2,
    .about-section h2,
    .contact-section > .container > h2 {
        font-size: 2rem;
    }

    .contact-grid {
        grid-template-columns: 1fr;
        gap: 3rem;
    }

    .contact-info {
        order: 2;
    }

    .contact-form-wrapper {
        order: 1;
        padding: 1.75rem;
    }

    .backer-logos {
        display: grid;
        grid-template-columns: repeat(2, 1fr);
        gap: 2rem;
        justify-items: center;
    }

    .backer-item img {
        max-height: 45px;
        max-width: 140px;
    }
}

@media (max-width: 600px) {
    .hero-split-content h1 {
        font-size: 2rem;
    }

    .hero-split-content .hero-subhead {
        font-size: 1rem;
    }

    .hero-split-image {
        min-height: 250px;
    }

    .product-quick-nav .container {
        flex-direction: column;
    }

    .product-quick-nav .btn {
        text-align: center;
    }

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

    .contact-section {
        padding: 3rem 0;
    }

    /* 规格表转为堆叠卡片 */
    .specs-table tr {
        display: flex;
        flex-direction: column;
        padding: 0.75rem 0;
    }

    .specs-table td {
        padding: 0.25rem 0;
    }

    .specs-table td:first-child {
        width: 100%;
        font-size: 0.9rem;
        color: var(--primary-blue);
    }

    .specs-table td:last-child {
        width: 100%;
        font-weight: 500;
        color: var(--text-dark);
    }

    .backed-intro {
        text-align: center;
        font-size: 1.25rem;
        margin-bottom: 2rem;
    }

    .backer-logos {
        grid-template-columns: repeat(2, 1fr);
        gap: 2rem;
    }

    .backer-item img {
        height: 40px;
    }

    .backer-dark-bg {
        padding: 0.75rem 1.25rem;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 1rem;
    }

    .nav-container {
        padding: 1rem;
    }

    .hero-split-content h1 {
        font-size: 1.8rem;
    }

    .hero-split-content {
        padding: 2.5rem 1.25rem;
    }

    .backer-logos {
        grid-template-columns: 1fr;
    }

    .btn {
        padding: 0.875rem 1.5rem;
    }

    .back-to-top {
        right: 1rem;
        bottom: 1rem;
    }
}

/* =========================================================
   17. 无障碍与动效降级
   ========================================================= */

a:focus-visible,
button:focus-visible,
input:focus-visible,
select:focus-visible,
textarea:focus-visible {
    outline: 3px solid var(--primary-blue);
    outline-offset: 2px;
}

@media (prefers-reduced-motion: reduce) {
    html {
        scroll-behavior: auto;
    }

    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }

    .btn-primary:hover,
    .btn-secondary:hover,
    .benefit-item:hover {
        transform: none;
    }
}

/* 打印 */
@media print {
    .nav,
    .mobile-toggle,
    .back-to-top,
    .product-quick-nav,
    .subtle-cta {
        display: none !important;
    }

    .hero-split {
        margin-top: 0;
    }

    body {
        color: #000;
    }
}