/* =========================================================
   联建光电 绿色主题首页 · 方案2（分屏 Hero + 数据带 + 卡片网格）
   原生 CSS（无预处理器） | jQuery 1.8.3 + Swiper + wow.js + animate.css
   ========================================================= */
:root {
  --green:        #18b15f;
  --green-dark:   #129a4f;
  --green-darker: #0c7a3e;
  --green-light:  #e8f8ef;
  --green-soft:   #f2fbf6;
  --ink:          #1d2a23;
  --gray:         #68756e;
  --line:         #e4efe8;
  --white:        #fff;
  --shadow:       0 12px 34px rgba(12,122,62,.12);
  --radius:       16px;
  --maxw:         1400px;
}
* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body,h1,h2,h3,h4,h5,h6,hr,p,blockquote,dl,dt,dd,ul,ol,li,pre,form,input,fieldset,legend,button,textarea,div,img{border:0 none; margin:0; padding:0; box-sizing:border-box; outline:0;}
body { font-family: "PingFang SC","Microsoft YaHei","Helvetica Neue",Arial,sans-serif; color: var(--ink); background: #fff; line-height: 1.7; -webkit-font-smoothing: antialiased; }
a { color: inherit; text-decoration: none; }
img { display: block; max-width: 100%; }
ul, ol { list-style: none; }
.container { width: var(--maxw); max-width: 92%; margin: 0 auto; }

/* 按钮 */
.btn-primary { display: inline-flex; align-items: center; gap: 8px; background: var(--green); color: #fff; padding: 13px 32px; border-radius: 40px; font-weight: 600; font-size: 15px; box-shadow: 0 8px 22px rgba(24,177,95,.4); transition: .25s; }
.btn-primary:hover { background: var(--green-dark); transform: translateY(-2px); }
.btn-line { display: inline-flex; align-items: center; gap: 8px; border: 1.5px solid rgba(255,255,255,.85); color: #fff; padding: 13px 32px; border-radius: 40px; font-weight: 600; font-size: 15px; transition: .25s; }
.btn-line:hover { background: #fff; color: var(--green-dark); }
.btn-text { display: inline-flex; align-items: center; gap: 6px; color: var(--green); font-weight: 600; font-size: 14px; transition: gap .25s, color .25s; }
.btn-text:hover { gap: 12px; color: var(--green-dark); }
.arrow { transition: transform .25s; }
.btn-primary:hover .arrow, .btn-line:hover .arrow, .btn-text:hover .arrow { transform: translateX(4px); }

/* 标题 */
.section-title { font-size: 32px; font-weight: 800; letter-spacing: 1px; }
.section-title.light { color: #fff; }
.section-sub { color: var(--gray); font-size: 15px; margin-top: 10px; }
.section-sub.light { color: rgba(255,255,255,.85); }
.pub-title { text-align: center; margin-bottom: 50px; }
.title-bar { display: block; width: 56px; height: 4px; border-radius: 4px; background: var(--green); margin: 18px auto 0; }

/* ===================== 透明吸顶导航 ===================== */
.site-header { position: fixed; top: 0; left: 0; right: 0; z-index: 1000; background: transparent; border-bottom: 1px solid rgba(255,255,255,.2); transition: background .3s, box-shadow .3s, border-color .3s; }
.site-header.scrolled, .site-header:hover { background: #fff; box-shadow: var(--shadow); border-bottom-color: var(--line); }
.header-inner { display: flex; align-items: stretch; height: 80px; gap: 0; }
.logo { display: flex; align-items: center; gap: 12px; flex: 0 0 auto; order: 1; padding-right: 24px; border-right: 1px solid transparent; transition: border-color .3s; }
.logo img { height: 40px; }
.logo .hs{display: block;}
.logo .bs{display: none;}

.site-header:hover .logo .hs,
.site-header.scrolled .logo .hs{display: none;}
.site-header:hover .logo .bs,
.site-header.scrolled .logo .bs{display: block;}

.logo-code { display: flex; flex-direction: column; line-height: 1.2; }
.logo-code span { font-size: 11px; color: rgba(255,255,255,.8); transition: color .3s; }
.logo-code b { font-size: 15px; color: var(--green); letter-spacing: 1px; }
.site-header.scrolled .logo-code span, .site-header:hover .logo-code span { color: var(--gray); }

.main-nav { flex: 1 1 auto; order: 2; display: flex; align-items: center; justify-content: center; padding: 0 24px; border-right: 1px solid transparent; transition: border-color .3s; }
.main-nav > ul { display: flex; gap: 4px; }
.main-nav > ul > li { position: relative; }
.main-nav > ul > li > a { display: flex; align-items: center; gap: 4px; padding: 10px 16px; font-size: 16px; font-weight: 500; color: #fff; border-radius: 8px; transition: color .25s, background .25s; }
.site-header.scrolled .main-nav > ul > li > a, .site-header:hover .main-nav > ul > li > a { color: var(--ink); }
.main-nav > ul > li > a:hover, .main-nav > ul > li.on > a { color: var(--green); background: rgba(255,255,255,.14); }
.site-header.scrolled .main-nav > ul > li > a:hover, .site-header:hover .main-nav > ul > li > a:hover { background: var(--green-light); }

/* 顶部导航当前页高亮（选中态） */
.main-nav > ul > li.active > a {  color: #fff; background: var(--green);}
.site-header.scrolled .main-nav > ul > li.active > a,
.site-header:hover .main-nav > ul > li.active > a { color: #fff; background: var(--green); }
.caret { width: 6px; height: 6px; border-right: 2px solid currentColor; border-bottom: 2px solid currentColor; transform: rotate(45deg); margin-left: 2px; color: rgba(255,255,255,.8); transition: .2s; }
.site-header.scrolled .caret, .site-header:hover .caret { color: var(--gray); }

.dropdown { position: absolute; top: 100%; left: 50%; transform: translateX(-50%) translateY(10px); min-width: 180px; background: #fff; border-radius: 12px; box-shadow: var(--shadow); padding: 10px; opacity: 0; visibility: hidden; transition: .25s; }
.has-drop:hover .dropdown { opacity: 1; visibility: visible; transform: translateX(-50%) translateY(4px); }
.has-drop:hover .caret { transform: rotate(-135deg); }
.dropdown a { display: block; padding: 10px 14px; border-radius: 8px; font-size: 14px; color: var(--ink); transition: .2s; }
.dropdown a:hover { background: var(--green-light); color: var(--green); }

.header-tools { flex: 0 0 auto; order: 3; display: flex; align-items: center; gap: 6px; padding-left: 24px; position: relative; }
.tool-btn { background: none; border: none; cursor: pointer; color: #fff; padding: 8px; border-radius: 8px; display: flex; transition: background .2s, color .2s; }
.site-header.scrolled .tool-btn, .site-header:hover .tool-btn { color: var(--ink); }
.site-header.scrolled .logo,
.site-header.scrolled .main-nav,
.site-header:hover .logo,
.site-header:hover .main-nav { }
.tool-btn:hover { background: rgba(255,255,255,.18); }
.site-header.scrolled .tool-btn:hover, .site-header:hover .tool-btn:hover { background: var(--green-light); color: var(--green); }
.search-panel { position: absolute; top: 110%; right: 0; width: 300px; background: #fff; border-radius: 12px; box-shadow: var(--shadow); padding: 12px; opacity: 0; visibility: hidden; transform: translateY(8px); transition: .25s; }
.search-panel.open { opacity: 1; visibility: visible; transform: translateY(0); }
.search-form { display: flex; align-items: center; gap: 8px; }
.search-form input { flex: 1; border: 1px solid var(--line); border-radius: 8px; padding: 9px 12px; font-size: 14px; outline: none; transition: border .2s; }
.search-form input:focus { border-color: var(--green); }
.search-submit { background: var(--green); border: none; color: #fff; width: 38px; height: 38px; border-radius: 8px; cursor: pointer; display: flex; align-items: center; justify-content: center; }

/* 语言选择 */
.lang-switch { position: relative; display: flex; align-items: center; }
.lang-btn { gap: 6px; font-size: 14px; font-weight: 500; line-height: 1; }
.lang-btn .lang-label { white-space: nowrap; }
.site-header.scrolled .lang-btn, .site-header:hover .lang-btn { color: var(--ink); }
.lang-btn:hover { background: rgba(255,255,255,.18); }
.site-header.scrolled .lang-btn:hover, .site-header:hover .lang-btn:hover { background: var(--green-light); color: var(--green); }
.lang-menu { position: absolute; top: 110%; right: 0; min-width: 132px; background: #fff; border-radius: 12px; box-shadow: var(--shadow); padding: 8px; opacity: 0; visibility: hidden; transform: translateY(8px); transition: .25s; z-index: 20; }
.lang-menu.open { opacity: 1; visibility: visible; transform: translateY(0); }
.lang-menu a { display: flex; align-items: center; justify-content: space-between; padding: 9px 12px; border-radius: 8px; font-size: 14px; color: var(--ink); transition: .2s; }
.lang-menu a:hover { background: var(--green-light); color: var(--green); }
.lang-menu a.on { color: var(--green); font-weight: 600; }
.lang-menu a.on::after { content: "✓"; font-weight: 700; }
.nav-toggle { display: none; margin-left: auto; background: none; border: none; color: #fff; cursor: pointer; align-self: center;}
.site-header.scrolled .nav-toggle, .site-header:hover .nav-toggle { color: var(--ink); }

/* ===================== Hero 轮播 ===================== */
.hero { position: relative; }
.hero-swiper { width: 100%; height: 100vh; min-height: 600px; position: relative; }
.hero-swiper .swiper-slide { position: relative; overflow: hidden; }
.hero-img { position: absolute; inset: 0; width: 100%; height: 100%; object-fit: cover; z-index: 1; transform: scale(1.08); transition: transform 7s ease; }
.swiper-slide-active .hero-img { transform: scale(1); }
.hero-mask { position: absolute; inset: 0; z-index: 2; background: linear-gradient(120deg, rgba(7,46,25,.78) 0%, rgba(7,46,25,.45) 50%, rgba(7,46,25,.25) 100%); }
.hero-caption { position: absolute; left: 0; right: 0; top: 50%; transform: translateY(-50%); z-index: 3; color: #fff; text-align: left; }
.hero-tag { display: inline-block; padding: 6px 18px; border: 1px solid rgba(255,255,255,.55); border-radius: 30px; font-size: 13px; letter-spacing: 1px; margin-bottom: 20px; }
.hero-caption h1 { font-size: 50px; font-weight: 800; text-shadow: 0 2px 16px rgba(0,0,0,.3); }
.hero-caption p { font-size: 18px; margin: 18px 0 30px; max-width: 720px; opacity: .95; }
.hero-actions { display: flex; gap: 16px; justify-content: flex-start; }
.hero-caption--center { text-align: center; }
.hero-caption--center p { margin-left: auto; margin-right: auto; }
.hero-caption--center .hero-actions { justify-content: center; }
.hero .swiper-pagination { bottom: 40px; }
.hero .swiper-pagination-bullet { width: 28px; height: 5px; border-radius: 4px; background: rgba(255,255,255,.5); opacity: 1; transition: .3s; }
.hero .swiper-pagination-bullet-active { background: var(--green); width: 46px; }
.scroll-hint { position: absolute; left: 50%; bottom: 24px; transform: translateX(-50%); z-index: 3; color: rgba(255,255,255,.85); animation: bounce 1.8s infinite; }
@keyframes bounce { 0%,100% { transform: translateX(-50%) translateY(0); } 50% { transform: translateX(-50%) translateY(8px); } }

/* ===================== 数据指标带 ===================== */
.stats { background: linear-gradient(120deg, var(--green-darker), var(--green)); padding: 56px 0; }
.stats-grid { display: grid; grid-template-columns: repeat(3,1fr); gap: 24px; text-align: center; color: #fff; }
.stat-item { white-space: nowrap; }
.stat-item b { display: inline-block; font-size: 46px; font-weight: 800; line-height: 1.1; vertical-align: baseline; }
.stat-item span { display: block; font-size: 15px; opacity: .9; }
.stat-unit { font-size: 24px; line-height: 1.1; font-weight: 700; margin-left: 3px; font-style: normal; vertical-align: baseline; }

/* ===================== 产品中心 卡片网格 ===================== */
/* 产品板块外层容器*/        .product-section {margin:0 auto;padding:4% 0;}
/* 头部标题区域*/        .section-header {text-align:center;margin-bottom:40px;}
.section-header h2 {font-size:48px;color:#0f3057;margin-bottom:16px;}
.section-header p {font-size:18px;color:#666666;line-height:1.6;max-width:900px;margin:0 auto;}
/* 产品卡片网格容器*/        .product-grid {display:grid;grid-template-columns:repeat(3,1fr);gap:24px;}
/* 单个产品卡片*/        .product-card {background-color:#f5f5f5;border-radius:12px;padding:30px 20px;display:flex;flex-direction:column;gap:32px;}
/* 卡片标题*/        .card-title {font-size:24px;font-weight:bold;color:#000000;}
.card-title a {color:inherit;text-decoration:none;}
/* 产品图片容器*/        .card-img-box {width:100%;text-align:center;}
.card-img-box img {max-width:90%;height:auto;}
/* 响应式适配：平板、手机*/        @media (max-width:992px) {.product-grid {grid-template-columns:repeat(2,1fr);}
.section-header h2 {font-size:36px;}
;}
@media (max-width:640px) {.product-grid {grid-template-columns:1fr;}
.section-header h2 {font-size:28px;}
.card-title {font-size:20px;}
;}


/* ===================== 解决方案 图标卡片 ===================== */

.home-projects {position:relative;padding:4% 0;}
.home-title2 {font-weight:600;font-size:48px;color:#00204a;text-align:center;text-transform:capitalize;line-height:1.4; color: #fff;}
.home-projects .home-title2 {color:#fff;}
.home-projects .project-nav {display:flex;flex-wrap:wrap;align-items:center;justify-content:center;margin-top:40px;}
.home-projects .project-nav li {text-align:center;width:200px;}
.home-projects .project-nav li p {white-space:nowrap;margin-top:10px; color: #fff;}
.home-projects .project-nav li .img {width:80px;height:80px;border-radius:5px;overflow:hidden;position:relative;display:inline-flex;align-items:center;justify-content:center;cursor:pointer;z-index:1;}
.home-projects .project-nav li .img em {font-size:40px; color: #fff;}
.home-projects .project-nav li .img::after {content:"";position:absolute;left:0;top:0;width:100%;height:100%;background:#fff;opacity:.1;z-index:-1;}
.home-projects .project-nav li .img::before {content:"";position:absolute;top:0;left:50%;transform:translateX(-50%);width:20px;height:3px;background: var(--green);border-radius:2px;}
.home-projects .project-nav li.act .img::before {background-color:#fff;}
.home-projects .project-nav li.act .img::after {background: var(--green);opacity:1;}
.home-projects .project-wrap {width:100%;margin-top:40px;}
.home-projects .project-wrap .project-content {display:flex;flex-wrap:wrap;}
.home-projects .project-wrap .swiper-slide .project-content {opacity:.35;transition:opacity .4s ease;}
.home-projects .project-wrap .swiper-slide-active .project-content {opacity:1;}
.home-projects .project-wrap .project-content>div {width:50%;}
.home-projects .project-wrap .project-content .left {overflow:hidden;border-radius:10px 0 0 10px;}
.home-projects .project-wrap .project-content .left img {width:100%;height:100%;object-fit:cover;}
.home-projects .project-wrap .project-content .right {background:#fff;box-shadow:0 2px 32px 11px rgba(53,53,53,.07);border-radius:0 10px 10px 0;padding:6% 5%;}
.home-projects .project-wrap .project-content .right .p1 {font-weight:700;font-size:36px;color:#080d41;}
.home-projects .project-wrap .project-content .right .p2 {line-height:1.8;font-size:16px;color:#656567;margin:40px 0 60px;}
.home-projects .project-wrap .project-content .right .more {min-width:180px;padding:0 15px;display:inline-flex;align-items:center;justify-content:center;color:#fff;height:47px;background: var(--green);border-radius:5px;transition:all .1s linear;}
.home-projects .project-wrap .project-content .right .more:hover em {transform:translateX(4px);}
.home-projects .project-wrap .project-content .right .more em {margin-left:10px;transition:all 0.2s ease;}
@keyframes projectanimate {0% {transform:scale(.5);opacity:0;}
100% {transform:scale(1);opacity:1;}
;}
.home-projects::before {content:"";display:block;width:100%;height:65%;position:absolute;top:0;left:0;background:no-repeat top;background-size:cover;background-image:url(../images/app_bg.jpg);z-index: -1 }
.home-projects .pd95 {position:relative;z-index:1;color:#fff;}
.home-projects .projects-des {line-height:1.75;text-align:center;max-width:550px;margin:0 auto;padding:10px 0;}



.solutions { padding:4% 0; background: linear-gradient(135deg, var(--green-darker), var(--green-dark)); }
.solution-grid { display: grid; grid-template-columns: repeat(4,1fr); gap: 24px; }
.solution-card { display: block; background: rgba(255,255,255,.08); border: 1px solid rgba(255,255,255,.16); border-radius: var(--radius); padding: 32px 26px; color: #fff; transition: transform .3s, background .3s; }
.solution-card:hover { transform: translateY(-8px); background: rgba(255,255,255,.16); }
.solu-ico { display: inline-flex; width: 56px; height: 56px; border-radius: 14px; background: rgba(255,255,255,.16); color: #fff; align-items: center; justify-content: center; margin-bottom: 18px; }
.solution-card h3 { font-size: 19px; font-weight: 700; margin-bottom: 10px; }
.solution-card p { font-size: 14px; color: rgba(255,255,255,.82); }

/* ===================== 应用案例 ===================== */
.cases { padding:0 0 4% 0; background: #fff; }
.case-grid { display: grid; grid-template-columns: 1fr; gap: 48px; counter-reset: case; }
.case-item { display: flex; align-items: stretch; border-radius: var(--radius); overflow: hidden; background: var(--green-soft); border: 1px solid var(--line); transition: transform .3s, box-shadow .3s; }
.case-item:hover { transform: translateY(-6px); box-shadow: var(--shadow); }
.case-item:nth-child(even) { flex-direction: row-reverse; }
.case-img { display: block; width: 50%; min-height: 380px; overflow: hidden; }
.case-img img { width: 100%; height: 100%; object-fit: cover; transition: transform .5s; }
.case-item:hover .case-img img { transform: scale(1.06); }
.case-body { width: 50%; padding: 50px 56px; display: flex; flex-direction: column; justify-content: center; }
.case-body .case-no::before { counter-increment: case; content: "CASE 0" counter(case); font-size: 13px; font-weight: 700; letter-spacing: 2px; color: var(--green); }
.case-body .case-no { margin-bottom: 14px; }
.case-body .case-tag { align-self: flex-start; font-size: 13px; font-weight: 600; color: var(--green); background: rgba(15,118,72,.10); padding: 5px 13px; border-radius: 20px; margin-bottom: 18px; }
.case-body h3 { font-size: 26px; font-weight: 700; margin-bottom: 16px; }
.case-body h3 a:hover { color: var(--green); }
.case-body .case-desc { color: var(--gray); line-height: 1.85; font-size: 15px; margin-bottom: 26px; }

/* ===================== 视频 CTA ===================== */
.video-cta { position: relative; padding: 8% 0; background-size: cover; background-position: center; background-attachment: fixed;  background-image: url(../images/a_bg.jpg);}
.video-mask { position: absolute; inset: 0; background: rgba(7,46,25,.74); }
.video-inner { position: relative; z-index: 2; text-align: center; color: #fff; }
.video-inner h2 { font-size: 36px; font-weight: 800; }
.video-inner p { font-size: 17px; margin: 16px auto 0; max-width: 80%; opacity: .95; }
.play-btn { margin-top: 30px; width: 78px; height: 78px; border-radius: 50%; background: var(--green); color: #fff; border: none; cursor: pointer; display: inline-flex; align-items: center; justify-content: center; box-shadow: 0 0 0 0 rgba(24,177,95,.5); animation: pulse 2s infinite; transition: background .25s; }
.play-btn:hover { background: var(--green-dark); }
@keyframes pulse { 0% { box-shadow: 0 0 0 0 rgba(24,177,95,.5);} 70% { box-shadow: 0 0 0 22px rgba(24,177,95,0);} 100% { box-shadow: 0 0 0 0 rgba(24,177,95,0);} }
.video-modal { position: fixed; inset: 0; z-index: 2000; background: rgba(0,0,0,.8); display: none; align-items: center; justify-content: center; }
.video-modal.show { display: flex; }
.video-modal-box { position: relative; width: 80%; max-width: 900px; }
.video-modal-box video { width: 100%; border-radius: 12px; background: #000; }
.video-close { position: absolute; top: -46px; right: 0; width: 40px; height: 40px; border-radius: 50%; background: rgba(255,255,255,.15); color: #fff; border: none; cursor: pointer; display: flex; align-items: center; justify-content: center; transition: background .2s; }
.video-close:hover { background: var(--green); }

/* ===================== 新闻 ===================== */
.news { padding:4% 0; background: var(--green-soft); }
.news-grid { display: grid; grid-template-columns: repeat(3,1fr); gap: 30px; }
.news-item { background: #fff; border-radius: var(--radius); overflow: hidden; border: 1px solid var(--line); transition: transform .3s, box-shadow .3s; }
.news-item:hover { transform: translateY(-6px); box-shadow: var(--shadow); }
.news-img { display: block; overflow: hidden; }
.news-img img { width: 100%; height: 100%; object-fit: cover; transition: transform .5s; }
.news-item:hover .news-img img { transform: scale(1.06); }
.news-body { padding: 22px 24px 26px; }
.news-date { color: var(--gray); font-size: 13px;  }
.news-title { font-size: 16px; line-height: 1.6; margin: 10px 0 16px; font-weight: 600; }
.news-title a:hover { color: var(--green); }
.news-desc { color: var(--gray); font-size: 14px; line-height: 1.7; margin-bottom: 16px; display: -webkit-box; -webkit-box-orient: vertical; -webkit-line-clamp: 3; overflow: hidden; }

/* ===================== 页脚 ===================== */
.site-footer { background: #0f231a; color: rgba(255,255,255,.8); }
.footer-top { display: grid; grid-template-columns: 1fr 1.7fr auto; gap: 50px; padding: 64px 0 50px; align-items: start; }
.footer-info .fbt { color: #fff; font-size: 20px; margin-bottom: 14px; }
.footer-hot { margin: 8px 0; font-size: 15px; }
.footer-hot b { color: var(--green); font-size: 20px; letter-spacing: 1px; }
.footer-info p { font-size: 14px; }
.footer-social { display: flex; gap: 14px; margin-top: 20px; }
.footer-social a { position: relative; width: 40px; height: 40px; border-radius: 50%; background: rgba(255,255,255,.08); display: flex; align-items: center; justify-content: center; transition: background .25s; }
.footer-social a:hover { background: var(--green); }
.footer-social img { width: 22px; display: block; }
.footer-social .qr-img { position: absolute; bottom:46px; left: 50%; transform: translateX(-50%) scale(.92); width:120px; border-radius: 10px; opacity: 0; visibility: hidden; transition: .25s; box-shadow: 0 8px 24px rgba(0,0,0,.35); z-index: 20; }
.footer-social .qr-img img{width: 120px; display: block;}

.footer-social .qr:hover .qr-img { opacity: 1; visibility: visible; transform: translateX(-50%) scale(1); }
.footer-nav { display: grid; grid-template-columns: repeat(4,1fr); gap: 24px; }
.footer-nav dt { color: #fff; font-weight: 700; font-size: 15px; margin-bottom: 14px; }
.footer-nav dd { margin-bottom: 10px; }
.footer-nav dd a { font-size: 14px; color: rgba(255,255,255,.7); transition: color .2s; }
.footer-nav dd a:hover { color: var(--green); }
.footer-qr { align-self: start; }
.footer-qr .qr-title { color: #fff; font-size: 15px; font-weight: 700; margin-bottom: 16px; }
.footer-qr .qr-list { display: flex; gap: 22px; }
.footer-qr .qr-item { text-align: center; }
.footer-qr .qr-item img { display: block; width: 100px; height: 100px; border-radius: 8px; background: #fff; padding: 6px; object-fit: contain; box-shadow: 0 4px 14px rgba(0,0,0,.25); }
.footer-qr .qr-item span { display: block; margin-top: 10px; font-size: 13px; color: rgba(255,255,255,.7); }
.footer-bottom { border-top: 1px solid rgba(255,255,255,.08); padding: 18px 0; }
.footer-bottom p { font-size: 13px; text-align: center; color: rgba(255,255,255,.55); }

/* 返回顶部 */
.back-top { position: fixed; right: 28px; bottom: 28px; z-index: 900; width: 48px; height: 48px; border-radius: 50%; background: var(--green); color: #fff; border: none; cursor: pointer; display: flex; align-items: center; justify-content: center; box-shadow: var(--shadow); opacity: 0; visibility: hidden; transform: translateY(14px); transition: .3s; }
.back-top.show { opacity: 1; visibility: visible; transform: translateY(0); }
.back-top:hover { background: var(--green-dark); }

/* ===================== 响应式 ===================== */
@media (max-width: 992px) {
  .section-title { font-size: 26px; }
  .hero-caption h1 { font-size: 36px; }
  .stats-grid, .product-grid, .solution-grid { grid-template-columns: repeat(2,1fr); }
  .news-grid, .footer-top { grid-template-columns: 1fr; gap: 36px; }
  .footer-nav { grid-template-columns: repeat(2,1fr); }
  .footer-qr { text-align: center; }
  .footer-qr .qr-list { justify-content: center; }
  .main-nav > ul { gap: 2px; }
  .main-nav > ul > li > a { padding: 10px 11px; font-size: 14px; }
}
@media (max-width: 991px) {
  .stat-item b { font-size: 38px; }
  .stat-unit { font-size: 20px; }
}
@media (max-width: 768px) {
  .header-inner { display: flex; }
  .logo { border-right: none; }
  .logo img{height: 28px;}
  .nav-toggle { display: flex; order: 3; }
  .header-tools { order: 2; margin-left: auto; }
  .main-nav { position: fixed; top: 80px; left: 0; right: 0; background: #fff; max-height: 0; overflow: hidden; transition: max-height .35s; box-shadow: var(--shadow);  display: block;}
  .main-nav.open { max-height: 80vh; overflow-y: auto; }
  .main-nav > ul { flex-direction: column; gap: 0; padding: 10px; }
  .main-nav > ul > li > a { padding: 14px 16px; color: var(--ink) !important; border-radius: 0; border-bottom: 1px solid var(--line); }
  .dropdown { position: static; transform: none; opacity: 1; visibility: visible; box-shadow: none; padding: 0 0 0 16px; display: none; }
  .has-drop.open .dropdown { display: block; }
  .caret { color: var(--gray) !important; }
  .hero-swiper { height: 70vh; min-height: 460px; }
  .hero-caption h1 { font-size: 28px; }
  .hero-caption p { font-size: 15px; }
  .stats-grid { grid-template-columns: 1fr 1fr; }
  .stat-item b { font-size: 32px; }
  .stat-unit { font-size: 18px; }
  .solution-grid { grid-template-columns: 1fr 1fr; }
  .case-item, .case-item:nth-child(even) { flex-direction: column; }
  .case-img, .case-body { width: 100%; }
  .case-img { min-height: 260px; }
  .case-body { padding: 34px 28px; }
  .video-cta { background-attachment: scroll; }
  .search-panel { width: 240px; }
}
@media (max-width: 520px) {
  .stat-item b { font-size: 28px; }
  .stat-unit { font-size: 16px; }
  .card-title{font-size:18px;}
}
@media (max-width: 480px) {
  .stat-item b { font-size: 22px; }
  .logo-code { display: none; }
  .stats-grid, .solution-grid, .product-grid, .news-grid { grid-template-columns: 1fr; }
}