/* ============================================================
   AI 教培官网样式表
   改主题色：改 :root 里的 --accent
   ============================================================ */

:root{
  --bg:#ffffff;
  --bg-alt:#f5f7fa;
  --panel:#ffffff;
  --ink:#0d1117;
  --ink-2:#333b47;
  --muted:#6b7280;
  --line:#e6e9f0;
  --accent:#2f5bff;
  --accent-soft:rgba(47,91,255,.10);
  --accent-ink:#ffffff;
  --hot:#ff5b3d;
  --shadow-sm:0 1px 2px rgba(16,20,30,.05), 0 1px 3px rgba(16,20,30,.04);
  --shadow-md:0 10px 30px -12px rgba(16,20,30,.18), 0 2px 8px rgba(16,20,30,.05);
  --shadow-lg:0 40px 80px -32px rgba(16,20,30,.35);
  --radius:16px;
  --wrap:1180px;
  --ease:cubic-bezier(.22,.7,.28,1);
}

[data-theme="dark"]{
  --bg:#0b0d12;
  --bg-alt:#11141b;
  --panel:#14181f;
  --ink:#f3f5f9;
  --ink-2:#c9cfda;
  --muted:#8c94a3;
  --line:#232833;
  --accent:#7b90ff;
  --accent-soft:rgba(123,144,255,.14);
  --accent-ink:#0b0d12;
  --hot:#ff7a5c;
  --shadow-sm:0 1px 2px rgba(0,0,0,.4);
  --shadow-md:0 12px 32px -14px rgba(0,0,0,.7);
  --shadow-lg:0 40px 80px -32px rgba(0,0,0,.8);
}

*,*::before,*::after{box-sizing:border-box}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}

body{
  margin:0;background:var(--bg);color:var(--ink-2);
  font-family:"PingFang SC","Hiragino Sans GB","Microsoft YaHei","Segoe UI",system-ui,-apple-system,sans-serif;
  font-size:16px;line-height:1.75;-webkit-font-smoothing:antialiased;
  transition:background .25s var(--ease), color .25s var(--ease);
}

img{max-width:100%;display:block}
a{color:inherit;text-decoration:none}
button{font:inherit;color:inherit;cursor:pointer}
h1,h2,h3{color:var(--ink)}

.wrap{width:100%;max-width:var(--wrap);margin:0 auto;padding:0 24px}
.wrap-narrow{max-width:820px}

/* ---------- 导航 ---------- */
.site-header{
  position:sticky;top:0;z-index:60;
  background:color-mix(in srgb, var(--bg) 82%, transparent);
  backdrop-filter:saturate(180%) blur(14px);-webkit-backdrop-filter:saturate(180%) blur(14px);
  border-bottom:1px solid transparent;
  transition:border-color .25s var(--ease), box-shadow .25s var(--ease);
}
.site-header.is-stuck{border-bottom-color:var(--line);box-shadow:var(--shadow-sm)}
.header-inner{display:flex;align-items:center;gap:20px;height:68px}

.brand{display:flex;align-items:center;gap:11px;flex:0 0 auto}
.brand-mark{
  width:38px;height:38px;border-radius:11px;flex:0 0 auto;display:grid;place-items:center;
  background:linear-gradient(140deg,var(--accent),#7c5cff);
  color:#fff;font-weight:700;font-size:15px;letter-spacing:.5px;
  box-shadow:0 6px 16px -6px color-mix(in srgb,var(--accent) 70%, transparent);
}
.brand-text{display:flex;flex-direction:column;line-height:1.2}
.brand-text strong{color:var(--ink);font-size:15.5px;font-weight:650}
.brand-text small{color:var(--muted);font-size:11.5px;letter-spacing:.4px}

.nav{display:flex;gap:2px;margin-left:auto}
.nav a{padding:8px 13px;border-radius:999px;font-size:14.5px;color:var(--ink-2);transition:background .2s var(--ease), color .2s var(--ease)}
.nav a:hover{background:var(--bg-alt);color:var(--ink)}
.nav a.is-active{background:var(--accent-soft);color:var(--accent);font-weight:600}

.header-actions{display:flex;align-items:center;gap:8px;margin-left:auto}
.nav+.header-actions{margin-left:0}

.icon-btn{
  width:38px;height:38px;border-radius:11px;border:1px solid var(--line);background:var(--panel);
  display:grid;place-items:center;color:var(--ink-2);
  transition:border-color .2s var(--ease), color .2s var(--ease), transform .2s var(--ease);
}
.icon-btn:hover{color:var(--ink);border-color:color-mix(in srgb,var(--ink) 22%, transparent)}
.icon-btn:active{transform:scale(.94)}
.menu-btn{display:none}

/* ---------- 按钮 ---------- */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:8px;
  padding:13px 24px;border-radius:999px;border:1px solid transparent;
  font-size:15px;font-weight:600;cursor:pointer;
  transition:transform .2s var(--ease), box-shadow .25s var(--ease), background .2s var(--ease), border-color .2s var(--ease);
}
.btn:active{transform:translateY(1px)}
.btn-primary{background:var(--accent);color:#fff;box-shadow:0 12px 26px -14px color-mix(in srgb,var(--accent) 85%, transparent)}
.btn-primary:hover{box-shadow:0 18px 34px -14px color-mix(in srgb,var(--accent) 90%, transparent)}
.btn-ghost{background:transparent;border-color:var(--line);color:var(--ink)}
.btn-ghost:hover{border-color:color-mix(in srgb,var(--ink) 25%, transparent);background:var(--bg-alt)}
.btn-sm{padding:9px 18px;font-size:14px}
.btn-block{width:100%}

/* ---------- 首屏 ---------- */
.hero{position:relative;overflow:hidden;padding:88px 0 72px}
.hero-glow{
  position:absolute;inset:-30% -10% auto -10%;height:620px;pointer-events:none;
  background:
    radial-gradient(46% 52% at 18% 32%, var(--accent-soft), transparent 68%),
    radial-gradient(38% 46% at 82% 10%, color-mix(in srgb,var(--accent) 16%, transparent), transparent 70%);
  filter:blur(6px);
}
.hero-inner{position:relative;max-width:920px}
.eyebrow{margin:0 0 14px;font-size:12.5px;font-weight:700;letter-spacing:2px;text-transform:uppercase;color:var(--accent)}
.hero-title{margin:0 0 20px;font-size:clamp(30px,5.2vw,54px);line-height:1.2;font-weight:800;letter-spacing:-.5px}
.hero-sub{margin:0 0 32px;font-size:clamp(15px,1.6vw,17.5px);color:var(--muted);max-width:680px}
.hero-cta{display:flex;flex-wrap:wrap;gap:12px;margin-bottom:52px}
.hero-stats{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:8px;margin:0;padding-top:32px;border-top:1px solid var(--line)}
.hero-stats dt{font-size:12.5px;color:var(--muted);margin-bottom:6px}
.hero-stats dd{margin:0;color:var(--ink);font-size:clamp(20px,2.6vw,28px);font-weight:750;letter-spacing:-.4px}
.hero-stats dd span{font-size:14px;font-weight:600;color:var(--muted);margin-left:3px}

/* ---------- 区块 ---------- */
.section{padding:84px 0}
.section-alt{background:var(--bg-alt)}
.section-head{display:flex;align-items:flex-end;justify-content:space-between;gap:24px;margin-bottom:34px;flex-wrap:wrap}
.section-head h2{margin:0;font-size:clamp(23px,3vw,32px);font-weight:780;letter-spacing:-.4px}
.section-note{margin:0;color:var(--muted);font-size:14px}

/* ---------- 作品 ---------- */
.filters{display:flex;flex-wrap:wrap;gap:8px;margin-bottom:26px}
.filters button{
  padding:8px 17px;border-radius:999px;border:1px solid var(--line);
  background:var(--panel);color:var(--ink-2);font-size:14px;transition:all .2s var(--ease);
}
.filters button:hover{border-color:color-mix(in srgb,var(--ink) 20%, transparent)}
.filters button.is-on{background:var(--ink);border-color:var(--ink);color:var(--bg);font-weight:600}

.grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:22px}
@keyframes cardIn{from{opacity:0;transform:translateY(14px)}to{opacity:1;transform:none}}
.card{
  position:relative;display:flex;flex-direction:column;overflow:hidden;padding:0;
  background:var(--panel);border:1px solid var(--line);border-radius:var(--radius);
  box-shadow:var(--shadow-sm);cursor:pointer;text-align:left;
  animation:cardIn .5s var(--ease) both;
  transition:transform .3s var(--ease), box-shadow .3s var(--ease), border-color .3s var(--ease);
}
.grid .card:nth-child(2){animation-delay:.05s}
.grid .card:nth-child(3){animation-delay:.1s}
.grid .card:nth-child(4){animation-delay:.15s}
.grid .card:nth-child(5){animation-delay:.2s}
.grid .card:nth-child(6){animation-delay:.25s}
.card:hover{transform:translateY(-4px);box-shadow:var(--shadow-md);border-color:color-mix(in srgb,var(--accent) 32%, var(--line))}
.card:focus-visible{outline:2px solid var(--accent);outline-offset:3px}

.card-cover{position:relative;aspect-ratio:16/10;overflow:hidden;display:grid;place-items:center;background:linear-gradient(140deg,var(--c1),var(--c2))}
.card-cover img{width:100%;height:100%;object-fit:cover}
.card-cover .idx{font-size:clamp(40px,7vw,62px);font-weight:800;letter-spacing:-2px;color:rgba(255,255,255,.9);text-shadow:0 6px 30px rgba(0,0,0,.25)}
.card-cover .play{
  position:absolute;left:14px;bottom:14px;
  width:36px;height:36px;border-radius:50%;display:grid;place-items:center;
  background:rgba(255,255,255,.22);border:1.5px solid rgba(255,255,255,.7);backdrop-filter:blur(4px);
  transition:transform .3s var(--ease), background .3s var(--ease);
}
.card:hover .play{transform:scale(1.1);background:rgba(255,255,255,.38)}
.card-cover .play svg{fill:#fff;margin-left:2px}
.card-cover .cat{position:absolute;left:14px;top:14px;padding:5px 12px;border-radius:999px;font-size:12px;font-weight:650;background:rgba(255,255,255,.92);color:#111826;backdrop-filter:blur(6px)}
.card-cover .metric{position:absolute;right:14px;bottom:14px;padding:5px 12px;border-radius:999px;font-size:12.5px;font-weight:650;background:rgba(12,14,20,.62);color:#fff;backdrop-filter:blur(6px)}

.card-body{padding:18px 20px 20px;display:flex;flex-direction:column;gap:9px;flex:1}
.card-body h3{margin:0;font-size:17px;font-weight:680;line-height:1.45;letter-spacing:-.2px}
.card-body p{margin:0;color:var(--muted);font-size:14px;line-height:1.7;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}
.card-foot{margin-top:auto;padding-top:12px;display:flex;align-items:center;justify-content:space-between;gap:10px;border-top:1px dashed var(--line);font-size:12.5px;color:var(--muted)}
.card-foot .more{color:var(--accent);font-weight:650;white-space:nowrap}

.empty{padding:56px 0;text-align:center;color:var(--muted);font-size:15px}
.works-tip{
  margin:26px 0 0;padding:16px 20px;border-radius:12px;font-size:14px;
  background:var(--accent-soft);color:var(--ink-2);border:1px solid color-mix(in srgb,var(--accent) 22%, transparent);
}

/* ---------- 课程卡 ---------- */
.courses{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:22px}
.course{
  position:relative;padding:28px 28px 26px;border-radius:var(--radius);display:flex;flex-direction:column;
  background:var(--panel);border:1px solid var(--line);box-shadow:var(--shadow-sm);
  transition:transform .3s var(--ease), box-shadow .3s var(--ease), border-color .3s var(--ease);
}
.course:hover{transform:translateY(-4px);box-shadow:var(--shadow-md);border-color:color-mix(in srgb,var(--accent) 30%, var(--line))}
.course-top{display:flex;align-items:center;gap:10px;margin-bottom:14px;flex-wrap:wrap}
.course-tag{padding:4px 12px;border-radius:999px;background:var(--accent-soft);color:var(--accent);font-size:12.5px;font-weight:650}
.course-hot{padding:4px 12px;border-radius:999px;background:color-mix(in srgb,var(--hot) 14%, transparent);color:var(--hot);font-size:12.5px;font-weight:700}
.course h3{margin:0 0 8px;font-size:20px;font-weight:740;letter-spacing:-.3px}
.course-sum{margin:0 0 18px;font-size:14.6px;color:var(--muted);line-height:1.75}
.course-meta{display:flex;flex-wrap:wrap;gap:8px 18px;margin:0 0 18px;padding:14px 16px;border-radius:12px;background:var(--bg-alt);font-size:13.5px;color:var(--ink-2)}
.course-meta b{color:var(--muted);font-weight:600;margin-right:5px}
.course-block{margin-bottom:16px}
.course-block h4{margin:0 0 8px;font-size:13px;font-weight:700;letter-spacing:1px;text-transform:uppercase;color:var(--muted)}
.course-block ul{margin:0;padding:0;list-style:none;display:grid;gap:7px}
.course-block li{position:relative;padding-left:19px;font-size:14.3px;color:var(--ink-2);line-height:1.7}
.course-block li::before{content:"";position:absolute;left:0;top:9px;width:7px;height:7px;border-radius:2px;background:var(--accent);opacity:.75}
.course-foot{margin-top:auto;padding-top:18px;border-top:1px solid var(--line);display:flex;align-items:center;justify-content:space-between;gap:14px;flex-wrap:wrap}
.course-price{font-size:19px;font-weight:760;color:var(--ink)}
.course-price small{display:block;font-size:12px;font-weight:600;color:var(--muted);letter-spacing:.3px}

/* ---------- 学习路径 ---------- */
.steps{list-style:none;margin:0;padding:0;display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:20px;counter-reset:s}
.steps li{position:relative;padding:26px 22px;border-radius:var(--radius);background:var(--panel);border:1px solid var(--line);box-shadow:var(--shadow-sm)}
.steps li::before{
  counter-increment:s;content:counter(s,decimal-leading-zero);
  display:block;font-size:13px;font-weight:800;letter-spacing:1px;color:var(--accent);margin-bottom:12px;
}
.steps li:not(:last-child)::after{
  content:"";position:absolute;right:-13px;top:50%;width:6px;height:6px;border-top:1.5px solid var(--line);border-right:1.5px solid var(--line);
  transform:translateY(-50%) rotate(45deg);
}
.steps h3{margin:0 0 8px;font-size:16.5px;font-weight:700}
.steps p{margin:0;font-size:14.2px;color:var(--muted);line-height:1.75}

/* ---------- 通用三卡 ---------- */
.cards-3{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:22px}
.svc{padding:28px 26px;border-radius:var(--radius);border:1px solid var(--line);background:var(--panel);box-shadow:var(--shadow-sm);transition:transform .3s var(--ease), box-shadow .3s var(--ease)}
.svc:hover{transform:translateY(-4px);box-shadow:var(--shadow-md)}
.svc-avatar{
  width:52px;height:52px;border-radius:14px;margin-bottom:16px;display:grid;place-items:center;
  background:linear-gradient(140deg,var(--accent),#7c5cff);color:#fff;font-size:19px;font-weight:750;
}
.svc h3{margin:0 0 4px;font-size:16.5px;font-weight:700}
.svc .role{margin:0 0 12px;font-size:13px;color:var(--accent);font-weight:650}
.svc p{margin:0;font-size:14.2px;color:var(--muted);line-height:1.75}

/* ---------- 学员反馈 ---------- */
.quotes{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:22px}
.quote{
  position:relative;padding:30px 26px 24px;border-radius:var(--radius);
  background:var(--panel);border:1px solid var(--line);box-shadow:var(--shadow-sm);display:flex;flex-direction:column;
}
.quote::before{
  content:"“";position:absolute;left:20px;top:6px;font-size:56px;line-height:1;font-weight:800;
  color:var(--accent);opacity:.16;font-family:Georgia,serif;
}
.quote p{margin:0 0 18px;font-size:14.8px;line-height:1.85;color:var(--ink-2)}
.quote .who{margin-top:auto;font-size:13px;font-weight:650;color:var(--muted);padding-top:14px;border-top:1px dashed var(--line)}

/* ---------- FAQ ---------- */
.faq{display:grid;gap:10px}
.faq details{
  border:1px solid var(--line);border-radius:14px;background:var(--panel);overflow:hidden;
  transition:border-color .2s var(--ease), box-shadow .2s var(--ease);
}
.faq details[open]{border-color:color-mix(in srgb,var(--accent) 28%, var(--line));box-shadow:var(--shadow-sm)}
.faq summary{
  cursor:pointer;list-style:none;padding:18px 52px 18px 20px;position:relative;
  font-size:15.5px;font-weight:650;color:var(--ink);
}
.faq summary::-webkit-details-marker{display:none}
.faq summary::after{
  content:"";position:absolute;right:22px;top:50%;width:9px;height:9px;
  border-right:2px solid var(--muted);border-bottom:2px solid var(--muted);
  transform:translateY(-70%) rotate(45deg);transition:transform .25s var(--ease);
}
.faq details[open] summary::after{transform:translateY(-30%) rotate(-135deg)}
.faq .faq-a{margin:0;padding:0 20px 20px;font-size:14.6px;line-height:1.85;color:var(--muted)}

/* ---------- 联系 ---------- */
.section-dark{background:#0d1016;color:#c9cfda}
[data-theme="dark"] .section-dark{background:#080a0e}
.section-dark .eyebrow{color:#8fa3ff}
.section-dark h2{margin:0 0 16px;color:#fff;font-size:clamp(23px,3vw,32px);font-weight:780;letter-spacing:-.4px}
.section-dark .about-text{color:#9aa3b2;margin:0 0 22px;font-size:15.5px;line-height:1.85}
.contact-grid{display:grid;grid-template-columns:1fr 320px;gap:56px;align-items:start}
.contact-list{list-style:none;margin:0;padding:0;display:grid;gap:12px}
.contact-list a,.contact-list div{
  display:flex;align-items:center;gap:14px;padding:17px 20px;border-radius:14px;
  background:rgba(255,255,255,.04);border:1px solid rgba(255,255,255,.09);
  transition:background .2s var(--ease), border-color .2s var(--ease), transform .2s var(--ease);
}
.contact-list a:hover{background:rgba(255,255,255,.08);border-color:rgba(255,255,255,.2);transform:translateY(-2px)}
.contact-list .ci{width:34px;height:34px;flex:0 0 auto;border-radius:10px;display:grid;place-items:center;background:rgba(255,255,255,.08);color:#fff}
.contact-list .cl{display:flex;flex-direction:column;line-height:1.45;min-width:0}
.contact-list .cl b{color:#fff;font-size:15px;font-weight:650}
.contact-list .cl span{color:#8e97a6;font-size:13.5px;word-break:break-all}

.contact-card{padding:26px;border-radius:18px;background:rgba(255,255,255,.05);border:1px solid rgba(255,255,255,.1);text-align:center}
.qr{
  width:100%;aspect-ratio:1;max-width:230px;margin:0 auto 16px;border-radius:14px;
  display:grid;place-items:center;text-align:center;padding:16px;
  background:rgba(255,255,255,.94);color:#8b93a2;font-size:13px;line-height:1.6;
  border:1px dashed rgba(255,255,255,.5);overflow:hidden;
}
.qr img{width:100%;height:100%;object-fit:contain}
.qr-cap{margin:0 0 6px;color:#fff;font-size:15px;font-weight:650}
.qr-tip{margin:0;color:#8e97a6;font-size:13px}
.qr-tip span{color:#8fa3ff;font-weight:650}

/* ---------- 页脚 ---------- */
.site-footer{border-top:1px solid var(--line);background:var(--bg)}
.footer-inner{display:flex;justify-content:space-between;align-items:center;gap:16px;flex-wrap:wrap;padding-top:28px;padding-bottom:88px;font-size:13.5px;color:var(--muted)}
.footer-left,.footer-right{display:flex;flex-direction:column;gap:5px}
.footer-left strong{color:var(--ink);font-size:15px}
.footer-right{text-align:right}
.footer-right a{color:var(--muted);border-bottom:1px solid transparent;transition:color .2s var(--ease), border-color .2s var(--ease)}
.footer-right a:hover{color:var(--accent);border-bottom-color:var(--accent)}

/* ---------- 移动端悬浮 CTA ---------- */
.sticky-cta{
  position:fixed;left:0;right:0;bottom:0;z-index:70;display:none;
  align-items:center;justify-content:space-between;gap:14px;padding:11px 18px calc(11px + env(safe-area-inset-bottom));
  background:color-mix(in srgb,var(--bg) 92%, transparent);
  backdrop-filter:blur(14px);-webkit-backdrop-filter:blur(14px);
  border-top:1px solid var(--line);
}
.sc-text{font-size:13.5px;color:var(--muted)}

/* ---------- 弹窗 ---------- */
.modal{position:fixed;inset:0;z-index:120;display:grid;place-items:center;padding:24px}
.modal[hidden]{display:none}
.modal-backdrop{position:absolute;inset:0;background:rgba(8,10,15,.55);backdrop-filter:blur(4px);animation:fade .22s var(--ease)}
.modal-panel{
  position:relative;width:min(760px,100%);max-height:88vh;overflow:auto;
  background:var(--panel);border:1px solid var(--line);border-radius:20px;
  box-shadow:var(--shadow-lg);animation:pop .28s var(--ease);
}
@keyframes fade{from{opacity:0}to{opacity:1}}
@keyframes pop{from{opacity:0;transform:translateY(14px) scale(.98)}to{opacity:1;transform:none}}
.modal-close{
  position:absolute;right:14px;top:14px;width:38px;height:38px;border-radius:11px;z-index:2;
  border:1px solid rgba(255,255,255,.25);background:rgba(12,14,20,.5);color:#fff;display:grid;place-items:center;backdrop-filter:blur(6px);
}
.modal-close:hover{background:rgba(12,14,20,.78)}
.modal-cover{aspect-ratio:16/8;display:grid;place-items:center;overflow:hidden;background:linear-gradient(140deg,var(--c1),var(--c2))}
.modal-cover img{width:100%;height:100%;object-fit:cover}
.modal-cover .idx{font-size:76px;font-weight:800;color:rgba(255,255,255,.92);letter-spacing:-3px}
.modal-body{padding:28px 30px 32px}
.modal-tags{display:flex;gap:8px;flex-wrap:wrap;margin-bottom:12px}
.modal-tags span{padding:5px 12px;border-radius:999px;background:var(--accent-soft);color:var(--accent);font-size:12.5px;font-weight:650}
.modal-body h3{margin:0 0 12px;font-size:23px;font-weight:750;letter-spacing:-.3px}
.modal-desc{margin:0 0 20px;font-size:15.2px;line-height:1.85;color:var(--ink-2)}
.modal-points{display:grid;gap:10px;margin-bottom:22px}
.modal-points div{display:flex;gap:11px;padding:13px 16px;border-radius:12px;background:var(--bg-alt);border:1px solid var(--line);font-size:14.3px;color:var(--ink-2)}
.modal-points div::before{content:"";width:6px;height:6px;border-radius:50%;background:var(--accent);flex:0 0 auto;margin-top:8px}
.modal-meta{display:grid;grid-template-columns:repeat(auto-fit,minmax(110px,1fr));gap:14px;margin:0 0 22px;padding:18px 0 0;border-top:1px solid var(--line)}
.modal-meta dt{font-size:12.5px;color:var(--muted);margin-bottom:3px}
.modal-meta dd{margin:0;color:var(--ink);font-size:15px;font-weight:680}
.modal-actions{display:flex;gap:10px;flex-wrap:wrap}

/* ---------- 滚动显现 ---------- */
.reveal{opacity:0;transform:translateY(18px)}
.reveal.is-in{opacity:1;transform:none;transition:opacity .7s var(--ease), transform .7s var(--ease)}

/* ---------- 响应式 ---------- */
@media (max-width:1024px){
  .nav a{padding:8px 10px;font-size:14px}
}
@media (max-width:940px){
  .grid,.cards-3,.quotes{grid-template-columns:repeat(2,minmax(0,1fr))}
  .courses{grid-template-columns:1fr}
  .steps{grid-template-columns:repeat(2,minmax(0,1fr))}
  .steps li:nth-child(2)::after,.steps li:nth-child(4)::after{display:none}
  .contact-grid{grid-template-columns:1fr;gap:34px}
  .contact-card{max-width:360px}
}
@media (max-width:720px){
  .wrap{padding:0 18px}
  .nav{
    position:fixed;left:0;right:0;top:68px;flex-direction:column;gap:2px;padding:12px 18px 18px;
    background:var(--bg);border-bottom:1px solid var(--line);box-shadow:var(--shadow-md);
    transform:translateY(-12px);opacity:0;pointer-events:none;transition:all .22s var(--ease);
  }
  .nav.is-open{transform:none;opacity:1;pointer-events:auto}
  .nav a{padding:12px 14px;border-radius:12px;font-size:15.5px}
  .nav+.header-actions{margin-left:auto}
  .menu-btn{display:grid}
  .hide-sm{display:none}
  .hero{padding:56px 0 48px}
  .hero-stats{grid-template-columns:repeat(2,minmax(0,1fr));gap:20px 8px}
  .section{padding:60px 0}
  .grid,.cards-3,.quotes,.steps{grid-template-columns:1fr}
  .steps li::after{display:none !important}
  .modal{padding:12px}
  .modal-body{padding:22px 20px 26px}
  .sticky-cta{display:flex}
  .footer-inner{padding-bottom:100px;flex-direction:column;align-items:flex-start}
  .footer-right{text-align:left}
}
@media (prefers-reduced-motion:reduce){
  *{animation-duration:.01ms !important;transition-duration:.01ms !important}
  html{scroll-behavior:auto}
  .reveal{opacity:1;transform:none}
}

/* ============ 讲师图文介绍（单讲师） ============ */
.teacher-feature{
  display:grid;grid-template-columns:280px minmax(0,1fr);gap:32px;align-items:start;
  background:var(--panel);border:1px solid var(--line);border-radius:var(--radius);
  box-shadow:var(--shadow-sm);padding:28px;
}
.teacher-poster{
  position:relative;display:block;padding:0;border:0;background:none;cursor:zoom-in;border-radius:12px;overflow:hidden;
  box-shadow:var(--shadow-sm);
}
.teacher-poster img{display:block;width:100%;height:auto}
.teacher-poster .zoom-hint{
  position:absolute;left:0;right:0;bottom:0;padding:10px 0;text-align:center;
  font-size:13px;font-weight:600;color:#fff;background:linear-gradient(transparent,rgba(10,12,18,.78));
  opacity:0;transition:opacity .25s var(--ease);
}
.teacher-poster:hover .zoom-hint,.teacher-poster:focus-visible .zoom-hint{opacity:1}
.teacher-info h3{margin:0 0 6px;font-size:24px}
.teacher-info .role{color:var(--accent);font-weight:650;margin:0 0 14px}
.teacher-badges{display:flex;flex-wrap:wrap;gap:8px;margin:0 0 14px}
.teacher-badges span{
  padding:5px 12px;border-radius:999px;font-size:12.5px;font-weight:600;
  background:rgba(91,108,255,.1);color:var(--accent);border:1px solid rgba(91,108,255,.25);
}
.teacher-titles{font-weight:650;margin:0 0 12px}
.teacher-info > p{margin:0 0 12px;line-height:1.75}
.teacher-courses-title{margin:18px 0 10px;font-size:15px}
.teacher-courses{list-style:none;margin:0;padding:0;display:grid;gap:8px}
.teacher-courses li{
  display:flex;flex-wrap:wrap;align-items:baseline;gap:6px 10px;
  padding:10px 14px;border:1px solid var(--line);border-radius:10px;background:var(--bg);font-size:14px;
}
.teacher-courses li span{color:var(--muted);font-size:13px}

/* ============ 讲师海报灯箱 ============ */
.lightbox{
  position:fixed;inset:0;z-index:90;display:grid;place-items:center;
  background:rgba(8,10,16,.86);backdrop-filter:blur(4px);padding:24px;
}
.lightbox[hidden]{display:none}
.lightbox img{max-width:min(680px,92vw);max-height:88vh;border-radius:10px;box-shadow:0 24px 64px rgba(0,0,0,.5)}
.lightbox-close{
  position:absolute;top:18px;right:20px;width:42px;height:42px;border-radius:50%;border:0;cursor:pointer;
  background:rgba(255,255,255,.14);color:#fff;display:grid;place-items:center;
}
.lightbox-close:hover{background:rgba(255,255,255,.26)}

@media (max-width:820px){
  .teacher-feature{grid-template-columns:1fr;padding:20px}
  .teacher-poster{max-width:340px;margin:0 auto}
}

/* 讲师区改为单列大卡（覆盖旧的 .cards-3 三列布局） */
#teacherList{grid-template-columns:1fr}