/*
Theme Name: AIFILTECH
Theme URI: https://aifiltech.com
Author: Tuokai Environmental Technology
Description: 拓凯环保科技 - 柴油机尾气治理与高温烟气净化 - 轻量级B2B工业风格主题
Version: 1.2.8
Text Domain: topkat
Tags: b2b, industrial, environmental
*/

/* ==================== 设计令牌 & 全局基础 ==================== */
:root {
    /* 色彩 */
    --topkat-dark: #0B3B4C;
    --topkat-dark-2: #14556e;
    --topkat-green: #1E8E4E;
    --topkat-green-dark: #177a3f;
    --topkat-green-light: #4ec97f;
    --topkat-light: #f5f7f8;
    --topkat-gray: #555f66;
    --topkat-border: #e3e8eb;
    /* 圆角 / 阴影 */
    --topkat-radius: 14px;
    --topkat-shadow-sm: 0 2px 8px rgba(11,59,76,.06);
    --topkat-shadow-md: 0 8px 24px rgba(11,59,76,.10);
    --topkat-shadow-lg: 0 16px 40px rgba(11,59,76,.16);
    /* 字体 */
    --topkat-font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "HarmonyOS Sans SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
    --topkat-font-num: "DIN Alternate", "Bahnschrift", "Segoe UI", -apple-system, sans-serif;
}

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

html { scroll-behavior: smooth; }

body {
    font-family: var(--topkat-font);
    font-size: 15px;
    line-height: 1.75;
    color: #2f3a40;
    background: #fff;
    -webkit-font-smoothing: antialiased;
    text-rendering: optimizeLegibility;
}

h1, h2, h3, h4, h5, h6 { line-height: 1.35; }

a { color: var(--topkat-green); text-decoration: none; transition: color .2s; }
a:hover { color: var(--topkat-green-dark); }

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

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

/* ==================== 顶部导航 ==================== */
.topkat-header {
    background: var(--topkat-dark);
    color: #fff;
    padding: 0;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: 0 2px 8px rgba(0,0,0,.1);
}

.topkat-header .container { display: block; }

.header-row {
    display: flex;
    align-items: center;
    gap: 20px;
    padding: 10px 0;
}

.topkat-logo {
    display: flex;
    align-items: center;
    color: #fff;
    flex-shrink: 0;
}
.topkat-logo img {
    height: 180px;
    width: auto;
    max-width: 400px;
    object-fit: contain;
    background: transparent !important;
    display: block;
}
.topkat-logo .brand-en { font-size: 12px; opacity: 0.7; letter-spacing: 1px; }

.topkat-search {
    flex: 1;
    max-width: 460px;
    min-width: 200px;
    display: flex;
    align-items: center;
    margin: 0 12px;
}
.topkat-search-input {
    flex: 1;
    height: 36px;
    padding: 0 14px;
    font-size: 13.5px;
    font-family: inherit;
    color: #2b3a40;
    background: #fff;
    border: 1px solid #cfd8dc;
    border-right: none;
    border-radius: 18px 0 0 18px;
    outline: none;
    transition: border-color .2s;
}
.topkat-search-input:focus { border-color: var(--topkat-green); }
.topkat-search-btn {
    height: 36px;
    width: 46px;
    background: var(--topkat-green);
    color: #fff;
    border: 1px solid var(--topkat-green);
    border-left: none;
    border-radius: 0 18px 18px 0;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background .2s;
}
.topkat-search-btn:hover { background: var(--topkat-green-dark); border-color: var(--topkat-green-dark); }

.topkat-nav {
    display: flex;
    align-items: center;
    gap: 26px;
    flex-shrink: 0;
}
.topkat-nav a {
    color: #fff;
    font-size: 15.5px;
    font-weight: 500;
    letter-spacing: .3px;
    padding: 6px 0;
    border-bottom: 2px solid transparent;
    transition: all .2s;
    white-space: nowrap;
}
.topkat-nav a:hover,
.topkat-nav .current-menu-item a {
    color: var(--topkat-green-light);
    border-bottom-color: var(--topkat-green);
}

.topkat-nav .language-switcher {
    margin-left: 12px;
    padding-left: 14px;
    border-left: 1px solid rgba(255,255,255,.25);
    font-size: 14px;
    display: flex;
    align-items: center;
    gap: 6px;
    white-space: nowrap;
}
.language-switcher a,
.language-switcher span.lang-sep {
    color: rgba(255,255,255,.8);
    text-decoration: none;
    transition: color .2s;
}
.language-switcher a:hover,
.language-switcher a.lang-current {
    color: #fff;
    font-weight: 600;
}
.language-switcher a.lang-current { color: var(--topkat-green-light); }
.language-switcher .lang-sep { color: rgba(255,255,255,.4); }

/* ==================== Hero 主横幅 ==================== */
.topkat-hero {
    background: linear-gradient(135deg, var(--topkat-dark) 0%, var(--topkat-dark-2) 100%);
    color: #fff;
    padding: 96px 0 110px;
    text-align: center;
    position: relative;
    overflow: hidden;
}
.topkat-hero::before {
    content: '';
    position: absolute;
    inset: 0;
    background: radial-gradient(circle at 30% 50%, rgba(30,142,78,.28) 0%, transparent 70%);
}
.topkat-hero::after {
    content: '';
    position: absolute;
    inset: 0;
    background-image:
        linear-gradient(rgba(255,255,255,.035) 1px, transparent 1px),
        linear-gradient(90deg, rgba(255,255,255,.035) 1px, transparent 1px);
    background-size: 48px 48px;
    pointer-events: none;
}
.topkat-hero .container { position: relative; z-index: 1; }
.topkat-hero .hero-logo {
    text-align: center;
    margin-bottom: 28px;
    position: relative;
}
.topkat-hero .hero-logo img {
    height: 78px;
    width: auto;
    max-width: 260px;
    display: inline-block;
    background: transparent;
}
.topkat-hero h1 {
    font-size: clamp(28px, 3.6vw, 46px);
    font-weight: 800;
    line-height: 1.28;
    letter-spacing: 1px;
    margin-bottom: 18px;
    position: relative;
}
.topkat-hero .hero-eyebrow {
    font-size: 16px;
    font-weight: 600;
    letter-spacing: 2px;
    color: #6fd59a;
    margin-bottom: 14px;
    position: relative;
    text-transform: none;
}
.topkat-hero .hero-intro {
    max-width: 860px;
    margin: 0 auto 46px;
    font-size: 15.5px;
    line-height: 1.95;
    color: rgba(255,255,255,.85);
    position: relative;
    text-align: center;
}
.topkat-hero .hero-sub {
    max-width: 720px;
    margin: 0 auto 34px;
    font-size: 16.5px;
    line-height: 1.7;
    color: rgba(255,255,255,.92);
    position: relative;
    text-align: center;
}
.topkat-hero .hero-cta {
    display: flex;
    justify-content: center;
    gap: 18px;
    flex-wrap: wrap;
    margin-bottom: 42px;
    position: relative;
}
.topkat-hero .hero-cta .btn-cta {
    display: inline-block;
    padding: 16px 44px;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    letter-spacing: 1px;
    transition: all .3s;
}
.topkat-hero .hero-cta .btn-cta.btn-primary {
    background: var(--topkat-green);
    color: #fff;
    box-shadow: 0 6px 18px rgba(30,142,78,.35);
}
.topkat-hero .hero-cta .btn-cta.btn-primary:hover {
    background: var(--topkat-green-dark);
    color: #fff;
    transform: translateY(-2px);
    box-shadow: 0 10px 26px rgba(30,142,78,.45);
}
.topkat-hero .hero-cta .btn-cta.btn-ghost {
    background: transparent;
    color: #fff;
    border: 1.5px solid rgba(255,255,255,.55);
}
.topkat-hero .hero-cta .btn-cta.btn-ghost:hover {
    border-color: #fff;
    background: rgba(255,255,255,.10);
    color: #fff;
}

/* ==================== 数据统计卡片（全宽） ==================== */
.topkat-stats {
    background: linear-gradient(135deg, var(--topkat-green) 0%, var(--topkat-green-dark) 100%);
    padding: 44px 0;
}
.topkat-stats .container {
    max-width: 1140px;
    padding: 0 24px;
}
.topkat-stats .stat-cards {
    display: grid;
    grid-template-columns: repeat(6, 1fr);
    gap: 16px;
}
.topkat-stats .stat-card {
    background: #fff;
    color: var(--topkat-dark);
    border-radius: var(--topkat-radius);
    padding: 24px 12px 20px;
    text-align: center;
    box-shadow: var(--topkat-shadow-sm);
    transition: transform .3s, box-shadow .3s;
}
.topkat-stats .stat-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--topkat-shadow-md);
}
.topkat-stats .stat-icon {
    font-size: 30px;
    line-height: 1;
    margin-bottom: 12px;
}
.topkat-stats .stat-num {
    font-family: var(--topkat-font-num);
    font-size: clamp(17px, 1.7vw, 25px);
    font-weight: 800;
    color: var(--topkat-green);
    font-variant-numeric: tabular-nums;
    letter-spacing: .3px;
    line-height: 1.25;
}
.topkat-stats .stat-label {
    font-size: 13px;
    letter-spacing: .5px;
    color: var(--topkat-gray);
    margin-top: 6px;
}

/* ==================== 通用板块与区块标题体系 ==================== */
.topkat-section { padding: 88px 0; }
.topkat-section.section-alt { background: var(--topkat-light); }

.topkat-section h2 {
    text-align: center;
    color: var(--topkat-dark);
    font-size: clamp(26px, 3vw, 34px);
    font-weight: 700;
    line-height: 1.3;
    letter-spacing: .5px;
    margin-bottom: 12px;
}
.topkat-section .section-sub {
    text-align: center;
    color: var(--topkat-gray);
    font-size: 16px;
    line-height: 1.7;
    margin-bottom: 52px;
}

/* 区块标题组：eyebrow 小标 + 大标题 + 描述（一线 B2B 官网通用模式） */
.section-head {
    text-align: center;
    max-width: 720px;
    margin: 0 auto 56px;
}
.section-head .eyebrow {
    display: inline-flex;
    align-items: center;
    gap: 12px;
    color: var(--topkat-green);
    font-size: 13px;
    font-weight: 700;
    letter-spacing: .18em;
    text-transform: uppercase;
    margin-bottom: 14px;
}
.section-head .eyebrow::before,
.section-head .eyebrow::after {
    content: '';
    width: 26px;
    height: 2px;
    background: var(--topkat-green);
    border-radius: 2px;
}
.section-head h2 {
    font-size: clamp(26px, 3vw, 36px);
    color: var(--topkat-dark);
    font-weight: 700;
    line-height: 1.3;
    letter-spacing: .5px;
    margin-bottom: 14px;
}
.section-head .section-sub {
    color: var(--topkat-gray);
    font-size: 15.5px;
    line-height: 1.7;
    margin-bottom: 0;
}

/* ==================== 主打产品区块 ==================== */
.featured-products {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 28px;
}
.featured-card {
    background: #fff;
    border: 1px solid var(--topkat-border);
    border-radius: var(--topkat-radius);
    overflow: hidden;
    box-shadow: var(--topkat-shadow-sm);
    transition: transform .3s, box-shadow .3s, border-color .3s;
    display: flex;
    flex-direction: column;
}
.featured-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--topkat-shadow-lg);
    border-color: rgba(30,142,78,.35);
}
.featured-card .img-box {
    height: 220px;
    background: var(--topkat-light);
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
}
.featured-card .img-box img { max-height: 100%; transition: transform .4s; }
.featured-card:hover .img-box img { transform: scale(1.04); }
.featured-card .body {
    padding: 26px 28px 28px;
    display: flex;
    flex-direction: column;
    flex: 1;
}
.featured-card h3 {
    color: var(--topkat-dark);
    font-size: 19px;
    font-weight: 700;
    line-height: 1.45;
    margin-bottom: 12px;
}
.featured-card p {
    color: var(--topkat-gray);
    font-size: 14.5px;
    line-height: 1.75;
    flex: 1;
}
.featured-card .btn,
.category-card .btn {
    color: var(--topkat-green);
    font-weight: 600;
    font-size: 14.5px;
    display: inline-block;
    margin-top: 18px;
    padding-bottom: 2px;
    border-bottom: 2px solid transparent;
    transition: border-color .25s, color .25s;
    align-self: flex-start;
}
.featured-card .btn:hover,
.category-card .btn:hover {
    color: var(--topkat-green-dark);
    border-bottom-color: var(--topkat-green);
}

/* ==================== 产品分类（三大产品线） ==================== */
.category-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 28px;
}
.category-card {
    background: #fff;
    padding: 38px 30px 34px;
    border-radius: var(--topkat-radius);
    border: 1px solid var(--topkat-border);
    border-top: 3px solid var(--topkat-green);
    text-align: center;
    box-shadow: var(--topkat-shadow-sm);
    transition: transform .3s, box-shadow .3s, border-color .3s;
}
.category-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--topkat-shadow-md);
    border-top-color: var(--topkat-green-dark);
}
.category-card .icon {
    width: 64px;
    height: 64px;
    background: rgba(30,142,78,.08);
    border-radius: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 20px;
    color: var(--topkat-green);
    font-size: 30px;
}
.category-card .count {
    display: inline-block;
    color: var(--topkat-green);
    background: rgba(30,142,78,.08);
    font-weight: 700;
    font-size: 13px;
    letter-spacing: .5px;
    padding: 4px 14px;
    border-radius: 999px;
    margin-bottom: 16px;
}
.category-card h3 {
    color: var(--topkat-dark);
    font-size: 20px;
    font-weight: 700;
    line-height: 1.4;
    margin-bottom: 14px;
}
.category-card p {
    color: var(--topkat-gray);
    font-size: 14px;
    line-height: 1.8;
    margin-bottom: 8px;
}

/* ==================== 公司优势（浅色卡片） ==================== */
.advantages {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
}
.advantage {
    text-align: left;
    padding: 30px 22px;
    background: #fff;
    border: 1px solid var(--topkat-border);
    border-radius: var(--topkat-radius);
    box-shadow: var(--topkat-shadow-sm);
    color: var(--topkat-gray);
    transition: transform .3s, box-shadow .3s, border-color .3s;
}
.advantage:hover {
    transform: translateY(-5px);
    box-shadow: var(--topkat-shadow-md);
    border-color: rgba(30,142,78,.35);
}
.advantage .num {
    width: 46px;
    height: 46px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 0 16px;
    background: rgba(30,142,78,.10);
    border-radius: 12px;
    color: var(--topkat-green);
    font-size: 21px;
}
.advantage h4 {
    color: var(--topkat-dark);
    font-size: 16.5px;
    font-weight: 700;
    margin-bottom: 10px;
    letter-spacing: .5px;
}
.advantage p {
    color: var(--topkat-gray);
    font-size: 13.5px;
    line-height: 1.8;
}

/* ==================== 产品列表 (产品中心页) ==================== */
.product-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
}
.product-card {
    background: #fff;
    border: 1px solid var(--topkat-border);
    border-radius: var(--topkat-radius);
    overflow: hidden;
    box-shadow: var(--topkat-shadow-sm);
    transition: all .3s;
}
.product-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--topkat-shadow-md);
}
.product-card .img {
    width: 100%;
    height: 200px;
    object-fit: cover;
    background: var(--topkat-light);
}
.product-card .body { padding: 18px; }
.product-card h4 {
    font-size: 15px;
    color: var(--topkat-dark);
    font-weight: 600;
    margin-bottom: 8px;
    line-height: 1.5;
    min-height: 45px;
}
.product-card .cat-tag {
    display: inline-block;
    background: var(--topkat-light);
    color: var(--topkat-green);
    padding: 3px 10px;
    border-radius: 12px;
    font-size: 11px;
    margin-bottom: 8px;
}

/* ==================== 首页底部 CTA ==================== */
.topkat-cta {
    background: linear-gradient(135deg, var(--topkat-dark) 0%, var(--topkat-dark-2) 100%);
    color: #fff;
    padding: 110px 0;
    text-align: center;
    position: relative;
    overflow: hidden;
}
.topkat-cta::before {
    content: '';
    position: absolute;
    inset: 0;
    background: radial-gradient(circle at 70% 50%, rgba(30,142,78,.25) 0%, transparent 70%);
}
.topkat-cta::after {
    content: '';
    position: absolute;
    inset: 0;
    background-image:
        linear-gradient(rgba(255,255,255,.03) 1px, transparent 1px),
        linear-gradient(90deg, rgba(255,255,255,.03) 1px, transparent 1px);
    background-size: 48px 48px;
    pointer-events: none;
}
.topkat-cta .container { position: relative; z-index: 1; }
.topkat-cta h2 {
    font-size: clamp(28px, 3.6vw, 42px);
    font-weight: 800;
    line-height: 1.3;
    margin-bottom: 20px;
    letter-spacing: 1.5px;
    color: #fff;
}
.topkat-cta .cta-sub {
    max-width: 640px;
    margin: 0 auto 42px;
    font-size: 16px;
    line-height: 1.85;
    color: rgba(255,255,255,.85);
}
.topkat-cta .cta-actions {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 18px;
    flex-wrap: wrap;
}
.topkat-cta .btn-cta {
    display: inline-block;
    padding: 17px 46px;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    letter-spacing: 1px;
    transition: all .3s;
}
.topkat-cta .btn-cta.btn-primary {
    background: var(--topkat-green);
    color: #fff;
    box-shadow: 0 6px 18px rgba(30,142,78,.35);
}
.topkat-cta .btn-cta.btn-primary:hover {
    background: var(--topkat-green-dark);
    color: #fff;
    transform: translateY(-2px);
    box-shadow: 0 10px 26px rgba(30,142,78,.45);
}
.topkat-cta .btn-cta.btn-ghost {
    background: transparent;
    color: #fff;
    border: 1.5px solid rgba(255,255,255,.5);
}
.topkat-cta .btn-cta.btn-ghost:hover {
    border-color: #fff;
    background: rgba(255,255,255,.08);
    color: #fff;
}
/* 兼容旧 CTA 按钮（应用场景页等） */
.topkat-cta .btn-large {
    display: inline-block;
    background: transparent;
    color: #fff;
    padding: 16px 56px;
    border-radius: 9999px;
    font-size: 18px;
    font-weight: 600;
    border: 2px solid #fff;
    transition: all .3s;
}
.topkat-cta .btn-large:hover {
    background: #fff;
    color: var(--topkat-dark);
}

/* ==================== 页脚 ==================== */
.topkat-footer {
    background: var(--topkat-dark);
    color: #cdd5da;
    padding: 56px 0 20px;
}
.topkat-footer .container {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 40px;
}
.topkat-footer h5 {
    color: #fff;
    font-size: 15px;
    font-weight: 600;
    letter-spacing: 1px;
    margin-bottom: 18px;
}
.topkat-footer ul { list-style: none; }
.topkat-footer li {
    padding: 4px 0;
    font-size: 14px;
    line-height: 1.7;
}
.topkat-footer a { color: #cdd5da; transition: color .2s; }
.topkat-footer a:hover { color: var(--topkat-green-light); }
.topkat-footer .copyright {
    text-align: center;
    margin-top: 30px;
    padding-top: 20px;
    border-top: 1px solid rgba(255,255,255,.1);
    font-size: 13px;
}

/* ==================== 应用场景页：左右两栏 ==================== */
.applications-section { background: var(--topkat-light); }
.applications-section .section-sub {
    text-align: center;
    margin-bottom: 50px;
}
.scenario-list {
    display: flex;
    flex-direction: column;
    gap: 28px;
}
.scenario-row {
    display: grid;
    grid-template-columns: 1fr 1.2fr;
    gap: 0;
    align-items: stretch;
    background: #fff;
    border-radius: 16px;
    overflow: hidden;
    box-shadow: 0 4px 18px rgba(11, 59, 76, 0.06);
    transition: transform .3s, box-shadow .3s;
}
.scenario-row:hover {
    transform: translateY(-4px);
    box-shadow: 0 12px 32px rgba(11, 59, 76, 0.12);
}
.scenario-row.reverse .scenario-text { order: 2; }
.scenario-row.reverse .scenario-img  { order: 1; }
.scenario-row .scenario-text {
    padding: 50px 44px;
    display: flex;
    flex-direction: column;
    justify-content: center;
}
.scenario-row .scenario-tag {
    display: inline-block;
    background: rgba(30, 142, 78, 0.1);
    color: var(--topkat-green);
    padding: 6px 14px;
    border-radius: 20px;
    font-size: 13px;
    letter-spacing: 1px;
    margin-bottom: 18px;
    align-self: flex-start;
    font-weight: 600;
}
.scenario-row .scenario-text h3 {
    color: var(--topkat-dark);
    font-size: 24px;
    margin: 0 0 14px;
    line-height: 1.4;
    font-weight: 700;
}
.scenario-row .scenario-text p {
    color: var(--topkat-gray);
    line-height: 1.85;
    font-size: 15px;
    margin: 0;
}
.scenario-row .scenario-img {
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    min-height: 340px;
}
.applications-summary {
    text-align: center;
    margin-top: 60px;
    padding: 50px 40px;
    background: linear-gradient(135deg, #f7faf9 0%, #eef5f1 100%);
    border-radius: 16px;
}
.applications-summary p {
    max-width: 800px;
    margin: 0 auto 24px;
    color: var(--topkat-gray);
    font-size: 16px;
    line-height: 1.85;
}
.applications-summary .btn-large {
    background: var(--topkat-green);
    color: #fff;
    padding: 16px 44px;
    border-radius: 40px;
    border: 2px solid var(--topkat-green);
    font-size: 17px;
    font-weight: 600;
    display: inline-block;
    transition: all .3s;
}
.applications-summary .btn-large:hover {
    background: transparent;
    color: var(--topkat-green);
}

/* ==================== 文章详情 ==================== */
.topkat-content { padding: 50px 0; }
.topkat-content h1 {
    color: var(--topkat-dark);
    font-size: 32px;
    margin-bottom: 20px;
}
.topkat-content .featured-img {
    width: 100%;
    max-height: 400px;
    object-fit: cover;
    border-radius: 8px;
    margin-bottom: 30px;
}
.topkat-content .product-gallery {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 16px;
    margin-top: 30px;
}
.topkat-content .product-gallery img {
    width: 100%;
    border-radius: 4px;
}
.topkat-content p, .topkat-content li {
    color: #444;
    line-height: 1.85;
    margin-bottom: 14px;
}

/* ==================== 产品详情页轮播 ==================== */
.detail-layout {
    display: grid;
    grid-template-columns: 1fr 1.6fr;
    gap: 36px;
    align-items: start;
}
.detail-gallery-card {
    background: #fff;
    border-radius: 12px;
    padding: 20px;
    box-shadow: var(--topkat-shadow-sm);
    position: sticky;
    top: 100px;
}
.product-carousel { position: relative; }
.carousel-main {
    background: var(--topkat-light);
    border-radius: 10px;
    height: 360px;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    margin-bottom: 16px;
}
.carousel-main .carousel-slide {
    max-width: 100%;
    max-height: 100%;
    object-fit: contain;
    display: none;
    transition: opacity .3s;
}
.carousel-main .carousel-slide.active { display: block; }
.carousel-main.no-image span { color: #999; }
.carousel-thumbs {
    display: flex;
    gap: 10px;
    overflow-x: auto;
    padding-bottom: 4px;
}
.carousel-thumbs .thumb {
    width: 72px;
    height: 72px;
    border: 2px solid transparent;
    border-radius: 8px;
    overflow: hidden;
    cursor: pointer;
    background: var(--topkat-light);
    padding: 0;
    flex-shrink: 0;
}
.carousel-thumbs .thumb img { width: 100%; height: 100%; object-fit: cover; }
.carousel-thumbs .thumb.active { border-color: var(--topkat-green); }

.product-intro { margin-bottom: 40px; }
.product-intro h3,
.product-specs h3 {
    color: var(--topkat-dark);
    font-size: 22px;
    margin-bottom: 18px;
    padding-bottom: 10px;
    border-bottom: 2px solid var(--topkat-green);
    display: inline-block;
}
.product-intro p {
    color: #444;
    line-height: 1.9;
    margin-bottom: 14px;
    font-size: 15px;
}

.spec-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 14px;
    background: #fff;
    border-radius: 10px;
    overflow: hidden;
    box-shadow: 0 2px 10px rgba(0,0,0,.05);
}
.spec-table tr:nth-child(odd) { background: #f8fafb; }
.spec-table tr:nth-child(even) { background: #fff; }
.spec-table td {
    padding: 14px 18px;
    border-bottom: 1px solid #eef2f4;
    color: #444;
    width: 25%;
}
.spec-table td:nth-child(odd) {
    color: var(--topkat-dark);
    font-weight: 600;
    background: rgba(11,59,76,.04);
}
.spec-table tr:last-child td { border-bottom: none; }

/* ==================== 产品详情页 ==================== */
.breadcrumb {
    font-size: 14px;
    color: #7a8a92;
    margin-bottom: 18px;
}
.breadcrumb a { color: var(--topkat-green); }
.breadcrumb span { margin: 0 6px; color: #b8c4c9; }
.entry-title {
    color: var(--topkat-dark);
    font-size: 30px;
    line-height: 1.4;
    margin-bottom: 12px;
}
.entry-meta {
    display: flex;
    align-items: center;
    gap: 14px;
    margin-bottom: 24px;
    flex-wrap: wrap;
}
.entry-meta .prod-num {
    font-size: 13px;
    color: #7a8a92;
    background: #f0f4f5;
    padding: 5px 12px;
    border-radius: 20px;
}
.detail-gallery .featured-img {
    width: 100%;
    border-radius: 8px;
    margin-bottom: 0;
    border: 1px solid #e8edef;
}
.detail-actions {
    display: flex;
    gap: 14px;
    margin-top: 36px;
    flex-wrap: wrap;
}
.btn-alt {
    background: transparent;
    color: var(--topkat-green);
    border: 2px solid var(--topkat-green);
}
.btn-alt:hover { background: var(--topkat-green); color: #fff; }

/* ==================== 产品详情：基础信息卡 ==================== */
.product-info-bar {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 0;
    background: linear-gradient(135deg, #f7faf9 0%, #eef5f1 100%);
    border: 1px solid #d8e8df;
    border-radius: 10px;
    margin: 22px 0 14px;
    overflow: hidden;
}
.product-info-bar .info-item {
    padding: 16px 20px;
    text-align: center;
    border-right: 1px solid #d8e8df;
    display: flex;
    flex-direction: column;
    gap: 6px;
}
.product-info-bar .info-item:last-child { border-right: none; }
.product-info-bar .info-label {
    font-size: 12px;
    color: #6e7c83;
    letter-spacing: 1px;
}
.product-info-bar .info-value {
    font-size: 16px;
    font-weight: 600;
    color: var(--topkat-dark);
    word-break: break-all;
}

.product-keywords {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    align-items: center;
    padding: 0 0 22px;
}
.product-keywords .kw-label {
    font-size: 14px;
    color: #6e7c83;
    margin-right: 4px;
}
.product-keywords .kw-tag {
    background: #fff;
    color: var(--topkat-dark);
    border: 1px solid #d8e8df;
    border-radius: 20px;
    padding: 4px 12px;
    font-size: 13px;
}

/* ==================== 产品详情：分类介绍卡片 ==================== */
.detail-sections { margin-top: 50px; }
.sections-title {
    font-size: 24px;
    color: var(--topkat-dark);
    margin-bottom: 24px;
    padding-left: 14px;
    border-left: 4px solid var(--topkat-green);
    line-height: 1.2;
}
.section-card {
    background: #fff;
    border: 1px solid #e8edef;
    border-radius: 12px;
    margin-bottom: 20px;
    overflow: hidden;
    transition: box-shadow .25s, transform .25s;
}
.section-card:hover {
    box-shadow: 0 6px 24px rgba(11, 59, 76, 0.08);
    transform: translateY(-2px);
}
.section-title {
    font-size: 17px;
    color: var(--topkat-dark);
    margin: 0;
    font-weight: 600;
    letter-spacing: 1px;
    padding: 16px 22px;
    background: linear-gradient(90deg, #f7faf9 0%, #ffffff 100%);
    border-bottom: 1px solid #e8edef;
}
.section-body {
    padding: 22px 26px;
    line-height: 1.85;
    color: #38474d;
    font-size: 15px;
}
.section-body p { margin: 0 0 12px; }
.section-body p:last-child { margin-bottom: 0; }
.section-list {
    margin: 6px 0 12px;
    padding-left: 28px;
    list-style: decimal;
}
.section-list li {
    padding-left: 4px;
    margin-bottom: 8px;
    line-height: 1.85;
}
.section-list li::before { content: none; }

@media (max-width: 900px) {
    .product-info-bar { grid-template-columns: repeat(2, 1fr); }
    .product-info-bar .info-item:nth-child(2) { border-right: none; }
    .product-info-bar .info-item:nth-child(1),
    .product-info-bar .info-item:nth-child(2) {
        border-bottom: 1px solid #d8e8df;
    }
}
@media (max-width: 900px) {
    .detail-layout { grid-template-columns: 1fr; }
    .detail-gallery-card { position: static; }
    .carousel-main { height: 260px; }
    .spec-table td { width: auto; display: block; }
    .spec-table tr { display: block; margin-bottom: 10px; }
    .section-title { padding: 12px 16px; font-size: 15px; }
    .section-body { padding: 16px 18px; font-size: 14px; }
    .sections-title { font-size: 20px; }
}

/* 产品详细介绍插图 */
.section-body img.topkat-content-img {
    max-width: 100%;
    height: auto;
    display: block;
    margin: 16px auto;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.08);
}

/* ==================== 常见问题 FAQ ==================== */
.topkat-faq {
    background: var(--topkat-light);
    padding: 88px 0;
}
.topkat-faq .section-head { margin-bottom: 44px; }
.topkat-faq h2 {
    text-align: center;
    color: var(--topkat-dark);
    font-size: clamp(26px, 3vw, 34px);
    font-weight: 700;
    line-height: 1.3;
    margin-bottom: 40px;
}
.topkat-faq .faq-list {
    max-width: 860px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 14px;
}
.topkat-faq .faq-item {
    background: #fff;
    border: 1px solid var(--topkat-border);
    border-radius: 12px;
    overflow: hidden;
    transition: box-shadow .3s, border-color .3s;
}
.topkat-faq .faq-item[open] {
    box-shadow: var(--topkat-shadow-md);
    border-color: rgba(30,142,78,.4);
}
.topkat-faq .faq-item summary {
    list-style: none;
    cursor: pointer;
    padding: 19px 26px;
    font-size: 16px;
    font-weight: 600;
    letter-spacing: .3px;
    color: var(--topkat-dark);
    position: relative;
    padding-right: 60px;
    transition: color .2s;
}
.topkat-faq .faq-item summary:hover { color: var(--topkat-green-dark); }
.topkat-faq .faq-item summary::-webkit-details-marker { display: none; }
.topkat-faq .faq-item summary::after {
    content: '+';
    position: absolute;
    right: 24px;
    top: 50%;
    transform: translateY(-50%);
    font-size: 22px;
    font-weight: 400;
    color: var(--topkat-green);
    transition: transform .3s;
}
.topkat-faq .faq-item[open] summary::after {
    content: '\2212';
}
.topkat-faq .faq-answer {
    padding: 6px 26px 22px;
    color: var(--topkat-gray);
    font-size: 14.5px;
    line-height: 1.85;
    border-top: 1px dashed var(--topkat-border);
    margin-top: 4px;
}

/* ==================== 响应式 ==================== */
@media (max-width: 900px) {
    .container { padding: 0 18px; }
    .topkat-section { padding: 60px 0; }
    .section-head { margin-bottom: 38px; }
    .topkat-hero { padding: 56px 0 68px; }
    .topkat-hero .hero-logo img { height: 58px; }
    .topkat-hero h1 { font-size: 26px; margin-bottom: 14px; }
    .topkat-hero .hero-eyebrow { font-size: 13px; letter-spacing: 1.5px; margin-bottom: 12px; }
    .topkat-hero .hero-sub { font-size: 14px; line-height: 1.7; margin-bottom: 26px; }
    .topkat-hero .hero-cta { gap: 12px; margin-bottom: 34px; }
    .topkat-hero .hero-cta .btn-cta { padding: 13px 30px; font-size: 15px; }
    .topkat-hero .hero-intro {
        font-size: 14px;
        line-height: 1.8;
        text-align: left;
        margin-bottom: 34px;
    }
    .topkat-cta { padding: 72px 0; }
    .topkat-cta h2 { font-size: 26px; }
    .topkat-cta .cta-sub { font-size: 14.5px; margin-bottom: 30px; }
    .topkat-cta .btn-cta { padding: 14px 34px; font-size: 15px; }
    .topkat-cta .btn-large { padding: 14px 36px; font-size: 16px; }
    .topkat-logo img { height: 56px; max-width: 140px; }
    .featured-products, .category-grid { grid-template-columns: 1fr; }
    .product-grid { grid-template-columns: repeat(2, 1fr); }
    .scenario-row { grid-template-columns: 1fr; gap: 0; }
    .scenario-row.reverse .scenario-text { order: 2; }
    .scenario-row.reverse .scenario-img  { order: 1; }
    .scenario-row .scenario-text { padding: 28px 22px; }
    .scenario-row .scenario-text h3 { font-size: 20px; }
    .scenario-row .scenario-img { min-height: 220px; }
    .advantages { grid-template-columns: 1fr; }
    .topkat-stats { padding: 34px 0; }
    .topkat-stats .stat-cards { grid-template-columns: repeat(2, 1fr); gap: 12px; }
    .topkat-stats .stat-num { font-size: 22px; }
    .topkat-footer .container { grid-template-columns: 1fr; }
    .topkat-faq { padding: 60px 0; }
    .header-row { flex-wrap: wrap; gap: 10px; }
    .topkat-nav { margin-left: auto; gap: 10px; }
    .topkat-nav > a { display: none; }
    .topkat-nav .language-switcher { margin-left: 0; }
    .topkat-search { order: 3; flex-basis: 100%; max-width: 100%; margin: 0; }
}