/* ===== 博赛教育 全局样式 ===== */
:root{
    --primary:#1e5fd8;
    --primary-dark:#164bad;
    --primary-light:#3d8bff;
    --accent:#ff9f1c;
    --accent-dark:#f08800;
    --ink:#1f2d3d;
    --text:#4a5568;
    --muted:#8a97a8;
    --line:#e8edf3;
    --bg:#f5f8fc;
    --card:#ffffff;
    --shadow:0 12px 40px rgba(30,90,200,.10);
    --shadow-sm:0 6px 20px rgba(30,90,200,.08);
    --radius:16px;
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
body{
    font-family:"PingFang SC","Microsoft YaHei","Helvetica Neue",Arial,sans-serif;
    color:var(--text);background:var(--bg);line-height:1.7;font-size:15px;
    -webkit-font-smoothing:antialiased;
}
a{color:inherit;text-decoration:none;transition:.2s}
img{max-width:100%;display:block}
.container{max-width:1200px;margin:0 auto;padding:0 20px}

/* ===== 顶部信息条 ===== */
.topbar{background:var(--primary-dark);color:#dce7fb;font-size:13px}
.topbar-inner{display:flex;justify-content:space-between;align-items:center;height:38px}
.topbar-contact b{color:#fff}
@media(max-width:768px){.topbar-contact{display:none}}

/* ===== 轮播图 ===== */
.slider{position:relative;height:460px;overflow:hidden;background:#0d2a5e}
.slides{height:100%;position:relative}
.slide{position:absolute;inset:0;display:flex;align-items:center;
    background-size:cover;background-position:center;
    opacity:0;transform:scale(1.06);transition:opacity 1s ease,transform 6s ease;pointer-events:none}
.slide.active{opacity:1;transform:scale(1);pointer-events:auto}
.slide::after{content:"";position:absolute;inset:0;background:linear-gradient(90deg,rgba(8,28,70,.72),rgba(8,28,70,.15))}
.slide-caption{position:relative;z-index:2;color:#fff;max-width:1200px;margin:0 auto;padding:0 60px;width:100%}
.slide-caption h2{font-size:44px;font-weight:800;letter-spacing:1px;text-shadow:0 4px 20px rgba(0,0,0,.3);
    opacity:0;transform:translateY(30px);animation:slideUp .9s .25s forwards}
.slide-caption p{font-size:20px;margin-top:16px;opacity:0;transform:translateY(30px);animation:slideUp .9s .5s forwards}
.slide.active .slide-caption h2,.slide.active .slide-caption p{opacity:0;transform:translateY(30px);animation:slideUp .9s forwards}
.slide.active .slide-caption p{animation-delay:.25s}
@keyframes slideUp{to{opacity:1;transform:translateY(0)}}
.slider-arrow{position:absolute;top:50%;transform:translateY(-50%);z-index:5;
    width:48px;height:48px;border:none;border-radius:50%;cursor:pointer;
    background:rgba(255,255,255,.2);color:#fff;font-size:20px;backdrop-filter:blur(4px);transition:.2s}
.slider-arrow:hover{background:rgba(255,255,255,.38)}
.slider-arrow.prev{left:24px}.slider-arrow.next{right:24px}
.slider-dots{position:absolute;bottom:22px;left:50%;transform:translateX(-50%);z-index:5;display:flex;gap:10px}
.slider-dots .dot{width:11px;height:11px;border-radius:50%;background:rgba(255,255,255,.45);cursor:pointer;transition:.2s}
.slider-dots .dot.active{background:#fff;width:30px;border-radius:6px}
@media(max-width:768px){
    .slider{height:300px}
    .slide-caption{padding:0 24px}
    .slide-caption h2{font-size:26px}
    .slide-caption p{font-size:15px}
    .slider-arrow{display:none}
}

/* ===== 顶部导航 ===== */
.site-header{background:#fff;box-shadow:0 2px 16px rgba(0,0,0,.05);position:sticky;top:0;z-index:100}
.header-inner{display:flex;align-items:center;justify-content:space-between;height:78px}
.logo{display:flex;align-items:center;gap:12px}
.logo-mark{display:inline-flex;align-items:center;justify-content:center;width:46px;height:46px;border-radius:12px;
    background:linear-gradient(135deg,var(--primary),var(--primary-light));color:#fff;font-weight:800;font-size:18px;letter-spacing:1px}
.logo-text b{display:block;font-size:20px;color:var(--ink);font-weight:800}
.logo-text small{display:block;font-size:12px;color:var(--muted)}
.main-nav{display:flex;gap:6px}
.main-nav a{position:relative;padding:10px 18px;font-size:16px;color:var(--ink);border-radius:8px;font-weight:500}
.main-nav a::after{content:"";position:absolute;left:18px;right:18px;bottom:4px;height:3px;border-radius:3px;background:var(--primary);transform:scaleX(0);transition:.25s}
.main-nav a:hover{color:var(--primary)}
.main-nav a.active{color:var(--primary);font-weight:700}
.main-nav a.active::after,.main-nav a:hover::after{transform:scaleX(1)}
.nav-toggle{display:none;flex-direction:column;gap:5px;background:none;border:none;cursor:pointer;padding:8px}
.nav-toggle span{width:26px;height:3px;background:var(--ink);border-radius:2px;transition:.3s}
@media(max-width:900px){
    .main-nav{position:absolute;top:78px;left:0;right:0;background:#fff;flex-direction:column;gap:0;
        box-shadow:0 12px 30px rgba(0,0,0,.1);max-height:0;overflow:hidden;transition:max-height .3s}
    .main-nav.open{max-height:420px}
    .main-nav a{padding:16px 20px;border-bottom:1px solid var(--line);border-radius:0}
    .main-nav a::after{display:none}
    .nav-toggle{display:flex}
}

/* ===== 通用区块 ===== */
.site-main{min-height:50vh}
.section{padding:70px 0}
.section-alt{background:#fff}
.section-head{text-align:center;max-width:720px;margin:0 auto 48px}
.section-head .en{display:block;font-size:13px;letter-spacing:3px;color:var(--primary-light);text-transform:uppercase;font-weight:700;margin-bottom:8px}
.section-head h2{font-size:32px;color:var(--ink);font-weight:800}
.section-head h2 span{color:var(--primary)}
.section-head .divider{width:56px;height:4px;background:var(--accent);border-radius:3px;margin:16px auto 0}
.section-head p{margin-top:16px;color:var(--muted);font-size:15px}

/* 页面横幅 */
.page-banner{position:relative;height:240px;display:flex;align-items:center;justify-content:center;text-align:center;
    background:linear-gradient(135deg,var(--primary-dark),var(--primary-light));color:#fff;overflow:hidden}
.page-banner::before{content:"";position:absolute;inset:0;background:url('../images/pattern.svg');opacity:.15}
.page-banner h1{position:relative;font-size:38px;font-weight:800;z-index:2}
.page-banner p{position:relative;z-index:2;margin-top:10px;opacity:.9}
.breadcrumb{background:#fff;border-bottom:1px solid var(--line);font-size:14px;color:var(--muted)}
.breadcrumb .container{padding-top:16px;padding-bottom:16px}
.breadcrumb a:hover{color:var(--primary)}
.breadcrumb b{color:var(--ink)}

/* ===== 按钮 ===== */
.btn{display:inline-flex;align-items:center;gap:8px;padding:12px 28px;border-radius:10px;font-weight:600;font-size:15px;cursor:pointer;border:none;transition:.25s}
.btn-primary{background:var(--primary);color:#fff}
.btn-primary:hover{background:var(--primary-dark);transform:translateY(-2px);box-shadow:0 10px 24px rgba(30,90,200,.28)}
.btn-accent{background:var(--accent);color:#fff}
.btn-accent:hover{background:var(--accent-dark);transform:translateY(-2px)}
.btn-ghost{background:#fff;color:var(--primary);border:1.5px solid var(--primary)}
.btn-ghost:hover{background:var(--primary);color:#fff}

/* ===== 首页 特色 ===== */
.features{display:grid;grid-template-columns:repeat(4,1fr);gap:24px}
.feature-card{background:var(--card);border-radius:var(--radius);padding:34px 24px;text-align:center;box-shadow:var(--shadow-sm);transition:.3s;border:1px solid var(--line)}
.feature-card:hover{transform:translateY(-8px);box-shadow:var(--shadow)}
.feature-icon{width:64px;height:64px;margin:0 auto 18px;border-radius:16px;display:flex;align-items:center;justify-content:center;
    background:linear-gradient(135deg,#e8f0ff,#f5f9ff);font-size:30px}
.feature-card h3{font-size:18px;color:var(--ink);margin-bottom:10px}
.feature-card p{font-size:14px;color:var(--muted)}
@media(max-width:900px){.features{grid-template-columns:repeat(2,1fr)}}
@media(max-width:520px){.features{grid-template-columns:1fr}}

/* ===== 卡片网格 ===== */
.grid-3{display:grid;grid-template-columns:repeat(3,1fr);gap:28px}
.grid-4{display:grid;grid-template-columns:repeat(4,1fr);gap:24px}
@media(max-width:900px){.grid-3,.grid-4{grid-template-columns:repeat(2,1fr)}}
@media(max-width:560px){.grid-3,.grid-4{grid-template-columns:1fr}}

/* 课程卡片 */
.course-card{background:var(--card);border-radius:var(--radius);overflow:hidden;box-shadow:var(--shadow-sm);transition:.3s;border:1px solid var(--line);display:flex;flex-direction:column}
.course-card:hover{transform:translateY(-8px);box-shadow:var(--shadow)}
.course-card .thumb{height:180px;overflow:hidden;position:relative}
.course-card .thumb img{width:100%;height:100%;object-fit:cover;transition:.5s}
.course-card:hover .thumb img{transform:scale(1.08)}
.course-card .tag{position:absolute;top:14px;left:14px;background:rgba(30,95,216,.92);color:#fff;font-size:12px;padding:5px 12px;border-radius:20px}
.course-card .body{padding:20px 22px;flex:1;display:flex;flex-direction:column}
.course-card h3{font-size:18px;color:var(--ink);margin-bottom:8px}
.course-card .summary{font-size:14px;color:var(--muted);flex:1}
.course-card .more{margin-top:16px;color:var(--primary);font-weight:600;font-size:14px;display:inline-flex;align-items:center;gap:6px}
.course-card:hover .more{gap:12px}

/* 分类筛选 */
.cat-tabs{display:flex;flex-wrap:wrap;gap:12px;justify-content:center;margin-bottom:40px}
.cat-tabs a{padding:10px 24px;border-radius:30px;background:#fff;border:1px solid var(--line);color:var(--text);font-weight:500;font-size:15px}
.cat-tabs a:hover{border-color:var(--primary);color:var(--primary)}
.cat-tabs a.active{background:var(--primary);color:#fff;border-color:var(--primary)}

.cat-block{margin-bottom:56px}
.cat-block-head{display:flex;align-items:center;gap:14px;margin-bottom:26px;padding-bottom:16px;border-bottom:2px solid var(--line)}
.cat-block-head .bar{width:6px;height:26px;border-radius:3px;background:var(--primary)}
.cat-block-head h2{font-size:24px;color:var(--ink)}
.cat-block-head small{color:var(--muted);font-weight:400;font-size:14px}

/* ===== 讲师卡片 ===== */
.teacher-card{background:var(--card);border-radius:var(--radius);overflow:hidden;box-shadow:var(--shadow-sm);transition:.3s;text-align:center;border:1px solid var(--line)}
.teacher-card:hover{transform:translateY(-8px);box-shadow:var(--shadow)}
.teacher-card .photo{height:280px;overflow:hidden;background:#eef4ff}
.teacher-card .photo img{width:100%;height:100%;object-fit:cover;transition:.5s}
.teacher-card:hover .photo img{transform:scale(1.06)}
.teacher-card .body{padding:22px 18px}
.teacher-card h3{font-size:20px;color:var(--ink)}
.teacher-card .title{color:var(--primary);font-size:14px;margin:6px 0 12px;font-weight:600}
.teacher-card .summary{font-size:14px;color:var(--muted);min-height:44px}
.teacher-card .more{display:inline-block;margin-top:14px;color:var(--primary);font-weight:600;font-size:14px}

/* ===== 学在博赛 图库 ===== */
.gallery{display:grid;grid-template-columns:repeat(2,1fr);gap:30px}
.gallery-item{background:var(--card);border-radius:var(--radius);overflow:hidden;box-shadow:var(--shadow-sm);transition:.3s;border:1px solid var(--line)}
.gallery-item:hover{box-shadow:var(--shadow)}
.gallery-item .pic{height:300px;overflow:hidden}
.gallery-item .pic img{width:100%;height:100%;object-fit:cover;transition:.6s}
.gallery-item:hover .pic img{transform:scale(1.05)}
.gallery-item .caption{padding:24px 26px}
.gallery-item h3{font-size:20px;color:var(--ink);margin-bottom:10px}
.gallery-item p{color:var(--muted);font-size:15px}
@media(max-width:768px){.gallery{grid-template-columns:1fr}}

/* ===== 课程详情 ===== */
.detail-hero{display:grid;grid-template-columns:1fr 1.2fr;gap:40px;align-items:center;background:#fff;border-radius:var(--radius);padding:34px;box-shadow:var(--shadow-sm);border:1px solid var(--line)}
.detail-hero .cover{border-radius:12px;overflow:hidden;height:280px}
.detail-hero .cover img{width:100%;height:100%;object-fit:cover}
.detail-hero .tag{display:inline-block;background:#e8f0ff;color:var(--primary);font-size:13px;padding:6px 16px;border-radius:20px;margin-bottom:14px}
.detail-hero h1{font-size:30px;color:var(--ink);margin-bottom:14px}
.detail-hero .summary{font-size:16px;color:var(--text);margin-bottom:22px}
.detail-hero .actions{display:flex;gap:14px}
@media(max-width:768px){.detail-hero{grid-template-columns:1fr}.detail-hero .cover{height:220px}}

.content-block{background:#fff;border-radius:var(--radius);padding:36px 40px;box-shadow:var(--shadow-sm);border:1px solid var(--line);margin-top:30px}
.content-block .block-title{display:flex;align-items:center;gap:12px;font-size:22px;color:var(--ink);margin-bottom:22px}
.content-block .block-title .num{width:38px;height:38px;border-radius:10px;background:linear-gradient(135deg,var(--primary),var(--primary-light));color:#fff;display:flex;align-items:center;justify-content:center;font-size:18px;font-weight:800}
.content-block .rich{color:var(--text);font-size:15.5px;line-height:2}
.content-block .rich p{margin-bottom:12px}
.outline-list{list-style:none}
.outline-list li{display:flex;gap:14px;padding:16px 0;border-bottom:1px dashed var(--line);align-items:flex-start}
.outline-list li:last-child{border-bottom:none}
.outline-list .idx{flex:none;width:30px;height:30px;border-radius:50%;background:#e8f0ff;color:var(--primary);display:flex;align-items:center;justify-content:center;font-weight:700;font-size:14px}
.audience-list{list-style:none}
.audience-list li{padding:12px 0 12px 34px;position:relative;border-bottom:1px dashed var(--line)}
.audience-list li:last-child{border-bottom:none}
.audience-list li::before{content:"✔";position:absolute;left:0;top:12px;color:var(--accent);font-weight:800}

/* ===== 讲师详情 ===== */
.teacher-detail{display:grid;grid-template-columns:340px 1fr;gap:40px}
.teacher-detail .side{background:#fff;border-radius:var(--radius);overflow:hidden;box-shadow:var(--shadow-sm);border:1px solid var(--line);position:sticky;top:100px}
.teacher-detail .side .photo{height:380px;background:#eef4ff}
.teacher-detail .side .photo img{width:100%;height:100%;object-fit:cover}
.teacher-detail .side .info{padding:24px;text-align:center}
.teacher-detail .side h1{font-size:26px;color:var(--ink)}
.teacher-detail .side .title{color:var(--primary);font-weight:600;margin:8px 0}
.cert-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:18px;margin-top:20px}
.cert-grid a{border-radius:12px;overflow:hidden;border:1px solid var(--line);box-shadow:var(--shadow-sm);transition:.3s;background:#fff}
.cert-grid a:hover{transform:translateY(-4px);box-shadow:var(--shadow)}
.cert-grid img{width:100%;height:150px;object-fit:cover}
@media(max-width:768px){.teacher-detail{grid-template-columns:1fr}.teacher-detail .side{position:static}.cert-grid{grid-template-columns:repeat(2,1fr)}}

/* ===== 关于我们 ===== */
.about-intro{display:grid;grid-template-columns:1.2fr 1fr;gap:44px;align-items:center}
.about-intro .text .rich{font-size:15.5px;line-height:2.1;color:var(--text)}
.about-intro .text .rich p{margin-bottom:16px}
.about-pic{border-radius:var(--radius);overflow:hidden;box-shadow:var(--shadow)}
.about-pic img{width:100%;height:100%;object-fit:cover}
@media(max-width:768px){.about-intro{grid-template-columns:1fr}}
.stat-row{display:grid;grid-template-columns:repeat(4,1fr);gap:24px;margin-top:50px}
.stat{background:#fff;border-radius:var(--radius);padding:30px 20px;text-align:center;box-shadow:var(--shadow-sm);border:1px solid var(--line)}
.stat .num{font-size:38px;font-weight:800;color:var(--primary)}
.stat .lbl{color:var(--muted);margin-top:6px}
@media(max-width:560px){.stat-row{grid-template-columns:repeat(2,1fr)}}

/* 发展历程 时间线 */
.timeline{position:relative;max-width:860px;margin:0 auto}
.timeline::before{content:"";position:absolute;left:50%;top:0;bottom:0;width:3px;background:var(--line);transform:translateX(-50%)}
.tl-item{position:relative;width:50%;padding:16px 40px;margin-bottom:14px}
.tl-item:nth-child(odd){left:0;text-align:right}
.tl-item:nth-child(even){left:50%}
.tl-item .dot{position:absolute;top:24px;width:18px;height:18px;border-radius:50%;background:var(--primary);border:4px solid #fff;box-shadow:0 0 0 3px var(--primary-light)}
.tl-item:nth-child(odd) .dot{right:-9px}
.tl-item:nth-child(even) .dot{left:-9px}
.tl-card{background:#fff;border-radius:12px;padding:20px 24px;box-shadow:var(--shadow-sm);border:1px solid var(--line)}
.tl-card .year{font-size:26px;font-weight:800;color:var(--primary)}
.tl-card h3{font-size:17px;color:var(--ink);margin:6px 0}
.tl-card p{font-size:14px;color:var(--muted)}
@media(max-width:768px){
    .timeline::before{left:20px}
    .tl-item{width:100%;left:0!important;text-align:left!important;padding:16px 0 16px 52px}
    .tl-item .dot{left:11px!important;right:auto!important}
}

/* 联系方式 */
.contact-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:24px}
.contact-card{background:#fff;border-radius:var(--radius);padding:30px 24px;text-align:center;box-shadow:var(--shadow-sm);border:1px solid var(--line);transition:.3s}
.contact-card:hover{transform:translateY(-6px);box-shadow:var(--shadow)}
.contact-card .ic{width:60px;height:60px;margin:0 auto 16px;border-radius:50%;background:#e8f0ff;display:flex;align-items:center;justify-content:center;font-size:26px}
.contact-card h4{color:var(--ink);margin-bottom:8px}
.contact-card p{color:var(--muted);font-size:14px}
@media(max-width:768px){.contact-grid{grid-template-columns:repeat(2,1fr)}}

/* CTA 区块 */
.cta{background:linear-gradient(135deg,var(--primary),var(--primary-light));border-radius:var(--radius);padding:56px 40px;text-align:center;color:#fff;position:relative;overflow:hidden}
.cta h2{font-size:30px;font-weight:800;margin-bottom:12px}
.cta p{opacity:.92;font-size:16px;margin-bottom:26px}
.cta .btn-accent{box-shadow:0 12px 30px rgba(0,0,0,.2)}

/* 空状态 */
.empty{text-align:center;padding:80px 20px;color:var(--muted)}
.empty .ic{font-size:56px;margin-bottom:16px;opacity:.5}

/* ===== 页脚 ===== */
.site-footer{background:#101b30;color:#a9b7cc;margin-top:70px}
.footer-grid{display:grid;grid-template-columns:1.4fr 1fr 1.4fr;gap:40px;padding:56px 20px 40px}
.footer-logo{display:flex;align-items:center;gap:10px;color:#fff;font-size:20px;margin-bottom:14px}
.footer-col h4{color:#fff;font-size:16px;margin-bottom:18px}
.footer-col a{display:block;padding:6px 0;color:#a9b7cc}
.footer-col a:hover{color:#fff}
.footer-col p{padding:5px 0;font-size:14px}
.footer-desc{margin-top:10px;font-size:14px;opacity:.8}
.footer-bottom{border-top:1px solid rgba(255,255,255,.1)}
.footer-bottom .container{display:flex;justify-content:space-between;padding:20px;font-size:13px;color:#8494ad}
@media(max-width:768px){.footer-grid{grid-template-columns:1fr;gap:28px}.footer-bottom .container{flex-direction:column;gap:8px;text-align:center}}

/* 返回顶部 */
.back-top{position:fixed;right:26px;bottom:30px;width:48px;height:48px;border-radius:50%;border:none;background:var(--primary);color:#fff;font-size:22px;cursor:pointer;box-shadow:var(--shadow);opacity:0;visibility:hidden;transform:translateY(20px);transition:.3s;z-index:99}
.back-top.show{opacity:1;visibility:visible;transform:translateY(0)}
.back-top:hover{background:var(--primary-dark)}

/* ===== 滚动逐渐显示动画 ===== */
.reveal{opacity:0;transform:translateY(40px);transition:opacity .8s cubic-bezier(.2,.7,.3,1),transform .8s cubic-bezier(.2,.7,.3,1)}
.reveal.visible{opacity:1;transform:translateY(0)}
.reveal.d1{transition-delay:.1s}.reveal.d2{transition-delay:.2s}.reveal.d3{transition-delay:.3s}
.reveal.d4{transition-delay:.4s}.reveal.d5{transition-delay:.5s}.reveal.d6{transition-delay:.6s}