/* iOS 26 Liquid Glass — 长沙竞速科技 */
:root{
  --bg-1:#f6f3ff;--bg-2:#eef6ff;--bg-3:#fff1f6;
  --ink:#1d1d1f;--ink-2:#3a3a3c;--ink-3:#6e6e73;
  --line:rgba(0,0,0,.08);
  --glass:rgba(255,255,255,.55);
  --glass-strong:rgba(255,255,255,.78);
  --accent:#5b6cff;--accent-2:#ff5b8a;--accent-3:#26c6a6;
  --radius:22px;--radius-sm:14px;
  --shadow:0 10px 40px -12px rgba(60,40,140,.18),0 2px 8px rgba(60,40,140,.06);
  --shadow-soft:0 4px 20px -6px rgba(60,40,140,.12);
}
*{box-sizing:border-box;margin:0;padding:0}
html,body{font-family:-apple-system,BlinkMacSystemFont,"PingFang SC","Helvetica Neue","Segoe UI",sans-serif;color:var(--ink);background:#f7f5fb;line-height:1.6;-webkit-font-smoothing:antialiased}
body{
  min-height:100vh;
  background:
    radial-gradient(1000px 600px at 10% -10%, #e7d9ff 0%, transparent 60%),
    radial-gradient(900px 500px at 110% 10%, #ffd9e8 0%, transparent 60%),
    radial-gradient(800px 600px at 50% 110%, #d3eaff 0%, transparent 60%),
    linear-gradient(180deg,#fbfaff 0%,#f5f6ff 100%);
  background-attachment:fixed;
}
img{max-width:100%;display:block;border:0}
a{color:inherit;text-decoration:none}
.container{max-width:1180px;margin:0 auto;padding:0 22px}

/* ===== Glass primitives ===== */
.glass{
  background:var(--glass);
  -webkit-backdrop-filter:saturate(180%) blur(28px);
  backdrop-filter:saturate(180%) blur(28px);
  border:1px solid rgba(255,255,255,.6);
  border-radius:var(--radius);
  box-shadow:var(--shadow-soft);
}
.glass-strong{
  background:var(--glass-strong);
  -webkit-backdrop-filter:saturate(200%) blur(34px);
  backdrop-filter:saturate(200%) blur(34px);
}

/* ===== Nav ===== */
.nav{
  position:sticky;top:14px;z-index:50;margin:14px auto 0;max-width:1180px;
  padding:10px 18px;display:flex;align-items:center;justify-content:space-between;
  border-radius:999px;background:var(--glass-strong);
  -webkit-backdrop-filter:saturate(200%) blur(34px);backdrop-filter:saturate(200%) blur(34px);
  border:1px solid rgba(255,255,255,.7);box-shadow:var(--shadow-soft);
}
.brand{display:flex;align-items:center;gap:10px;font-weight:700;font-size:16px;letter-spacing:.2px}
.brand-mark{
  width:30px;height:30px;border-radius:9px;
  background:conic-gradient(from 210deg,#5b6cff,#ff5b8a,#26c6a6,#5b6cff);
  display:grid;place-items:center;color:#fff;font-weight:800;font-size:13px;
  box-shadow:0 6px 14px rgba(91,108,255,.35);
}
.nav-links{display:flex;gap:6px;align-items:center}
.nav-links a{
  padding:8px 14px;border-radius:999px;color:var(--ink-2);font-size:14px;font-weight:500;
  transition:.2s;
}
.nav-links a:hover{background:rgba(91,108,255,.1);color:var(--accent)}
.nav-cta{
  padding:9px 16px;border-radius:999px;background:var(--ink);color:#fff!important;font-weight:600;
}
.nav-toggle{display:none;background:none;border:0;font-size:22px;cursor:pointer;color:var(--ink)}
@media(max-width:780px){
  .nav{margin-top:10px;padding:8px 14px}
  .nav-links{display:none;position:absolute;top:62px;left:14px;right:14px;flex-direction:column;align-items:stretch;padding:10px;border-radius:18px;background:var(--glass-strong);-webkit-backdrop-filter:blur(30px);backdrop-filter:blur(30px);border:1px solid rgba(255,255,255,.7);box-shadow:var(--shadow)}
  .nav-links.open{display:flex}
  .nav-links a{padding:11px 14px;border-radius:12px}
  .nav-toggle{display:block}
}

/* ===== Hero ===== */
.hero{padding:70px 0 40px;text-align:center;position:relative}
.hero-eyebrow{
  display:inline-flex;align-items:center;gap:8px;padding:7px 14px;border-radius:999px;
  background:rgba(255,255,255,.7);border:1px solid rgba(255,255,255,.7);
  -webkit-backdrop-filter:blur(20px);backdrop-filter:blur(20px);
  font-size:13px;color:var(--ink-2);font-weight:500;margin-bottom:22px;
}
.hero-eyebrow::before{content:"";width:6px;height:6px;border-radius:50%;background:var(--accent-3);box-shadow:0 0 0 4px rgba(38,198,166,.2)}
.hero h1{
  font-size:clamp(34px,5.4vw,62px);font-weight:800;line-height:1.08;letter-spacing:-.02em;
  background:linear-gradient(120deg,#1d1d1f 30%,#5b6cff 60%,#ff5b8a 95%);
  -webkit-background-clip:text;background-clip:text;color:transparent;margin-bottom:18px;
}
.hero p.lead{max-width:640px;margin:0 auto 28px;color:var(--ink-3);font-size:17px}
.hero-cta{display:flex;gap:12px;justify-content:center;flex-wrap:wrap}
.btn{
  display:inline-flex;align-items:center;gap:8px;padding:13px 22px;border-radius:999px;
  font-weight:600;font-size:15px;cursor:pointer;border:0;transition:.2s;
}
.btn-primary{background:var(--ink);color:#fff}
.btn-primary:hover{transform:translateY(-2px);box-shadow:0 12px 28px -8px rgba(0,0,0,.35)}
.btn-ghost{background:rgba(255,255,255,.7);color:var(--ink);border:1px solid rgba(0,0,0,.06)}
.btn-ghost:hover{background:#fff}

.hero-stats{
  display:grid;grid-template-columns:repeat(4,1fr);gap:14px;margin-top:48px;
  max-width:880px;margin-left:auto;margin-right:auto;
}
.hero-stats .stat{padding:18px 14px;text-align:center}
.hero-stats .stat .num{font-size:26px;font-weight:800;color:var(--accent);letter-spacing:-.02em}
.hero-stats .stat .lbl{font-size:13px;color:var(--ink-3);margin-top:4px}
@media(max-width:680px){.hero-stats{grid-template-columns:repeat(2,1fr)}}

/* ===== Section ===== */
.section{padding:60px 0}
.sec-head{text-align:center;margin-bottom:38px}
.sec-head .tag{font-size:13px;font-weight:600;color:var(--accent);text-transform:uppercase;letter-spacing:.12em}
.sec-head h2{font-size:clamp(26px,3.6vw,38px);font-weight:800;letter-spacing:-.01em;margin:8px 0 8px}
.sec-head p{color:var(--ink-3);max-width:580px;margin:0 auto}

/* ===== Course Cards ===== */
.course-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:22px}
@media(max-width:920px){.course-grid{grid-template-columns:repeat(2,1fr)}}
@media(max-width:600px){.course-grid{grid-template-columns:1fr}}
.course-card{
  border-radius:var(--radius);overflow:hidden;background:var(--glass-strong);
  -webkit-backdrop-filter:blur(28px);backdrop-filter:blur(28px);
  border:1px solid rgba(255,255,255,.7);box-shadow:var(--shadow-soft);
  transition:.25s;cursor:pointer;display:flex;flex-direction:column;
}
.course-card:hover{transform:translateY(-4px);box-shadow:var(--shadow)}
.course-thumb{position:relative;aspect-ratio:16/10;overflow:hidden;background:#eee}
.course-thumb img{width:100%;height:100%;object-fit:cover;transition:.5s}
.course-card:hover .course-thumb img{transform:scale(1.06)}
.course-tag{
  position:absolute;top:12px;left:12px;padding:5px 11px;border-radius:999px;
  background:rgba(255,255,255,.85);-webkit-backdrop-filter:blur(14px);backdrop-filter:blur(14px);
  font-size:12px;font-weight:600;color:var(--ink);
}
.course-body{padding:18px 18px 20px;display:flex;flex-direction:column;flex:1}
.course-title{font-size:17px;font-weight:700;letter-spacing:-.005em;margin-bottom:6px}
.course-desc{font-size:13.5px;color:var(--ink-3);margin-bottom:14px;flex:1}
.course-foot{display:flex;align-items:center;justify-content:space-between;padding-top:12px;border-top:1px dashed rgba(0,0,0,.08)}
.price{font-size:20px;font-weight:800;color:var(--accent-2);letter-spacing:-.01em}
.price small{font-size:12px;color:var(--ink-3);font-weight:500;margin-left:4px}
.course-foot .meta{font-size:12.5px;color:var(--ink-3)}
.stars{color:#ff9f0a;font-size:13px;letter-spacing:1px}

/* ===== Features ===== */
.feat-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}
@media(max-width:820px){.feat-grid{grid-template-columns:1fr 1fr}}
@media(max-width:560px){.feat-grid{grid-template-columns:1fr}}
.feat{padding:26px 22px;border-radius:var(--radius)}
.feat-icon{
  width:46px;height:46px;border-radius:14px;display:grid;place-items:center;
  font-size:22px;margin-bottom:14px;color:#fff;
}
.feat-1 .feat-icon{background:linear-gradient(135deg,#5b6cff,#7a4dff)}
.feat-2 .feat-icon{background:linear-gradient(135deg,#ff5b8a,#ff9f0a)}
.feat-3 .feat-icon{background:linear-gradient(135deg,#26c6a6,#5b6cff)}
.feat-4 .feat-icon{background:linear-gradient(135deg,#7a4dff,#ff5b8a)}
.feat-5 .feat-icon{background:linear-gradient(135deg,#ff9f0a,#ff5b8a)}
.feat-6 .feat-icon{background:linear-gradient(135deg,#26c6a6,#7a4dff)}
.feat h3{font-size:16px;margin-bottom:6px}
.feat p{color:var(--ink-3);font-size:14px}

/* ===== Reviews ===== */
.review-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}
@media(max-width:820px){.review-grid{grid-template-columns:1fr}}
.review{padding:24px;border-radius:var(--radius)}
.review .who{display:flex;align-items:center;gap:12px;margin-bottom:12px}
.avatar{width:42px;height:42px;border-radius:50%;background:linear-gradient(135deg,#5b6cff,#ff5b8a);display:grid;place-items:center;color:#fff;font-weight:700}
.review .name{font-weight:600;font-size:14.5px}
.review .role{font-size:12.5px;color:var(--ink-3)}
.review p{font-size:14px;color:var(--ink-2)}
.review .stars{margin-bottom:8px}

/* ===== Footer ===== */
.footer{
  margin-top:50px;padding:40px 0 30px;
  background:rgba(255,255,255,.5);
  -webkit-backdrop-filter:blur(20px);backdrop-filter:blur(20px);
  border-top:1px solid rgba(0,0,0,.05);
}
.foot-cols{display:grid;grid-template-columns:1.4fr 1fr 1fr 1fr;gap:32px;margin-bottom:30px}
@media(max-width:780px){.foot-cols{grid-template-columns:1fr 1fr}}
.foot-cols h4{font-size:14px;margin-bottom:14px}
.foot-cols a,.foot-cols p{font-size:13px;color:var(--ink-3);display:block;padding:3px 0}
.foot-cols a:hover{color:var(--accent)}
.foot-bottom{
  border-top:1px solid rgba(0,0,0,.06);padding-top:18px;display:flex;justify-content:space-between;
  flex-wrap:wrap;gap:10px;font-size:12.5px;color:var(--ink-3);
}
.foot-bottom a{color:var(--ink-3)}
.foot-bottom a:hover{color:var(--accent)}

/* ===== Back to top ===== */
#backTop{
  position:fixed;right:20px;bottom:20px;width:46px;height:46px;border-radius:50%;
  background:var(--glass-strong);-webkit-backdrop-filter:blur(28px);backdrop-filter:blur(28px);
  border:1px solid rgba(255,255,255,.7);box-shadow:var(--shadow);
  display:none;place-items:center;cursor:pointer;color:var(--ink);font-size:20px;z-index:60;
  transition:.2s;
}
#backTop:hover{transform:translateY(-3px)}
#backTop.show{display:grid}

/* ===== AI Chat Float ===== */
#aiChat{
  position:fixed;right:20px;bottom:80px;z-index:60;
}
#aiChat .ai-btn{
  width:56px;height:56px;border-radius:50%;cursor:pointer;
  background:linear-gradient(135deg,#5b6cff,#ff5b8a);color:#fff;
  display:grid;place-items:center;font-size:24px;
  box-shadow:0 12px 30px -6px rgba(91,108,255,.5);transition:.2s;border:0;
}
#aiChat .ai-btn:hover{transform:scale(1.06)}
#aiChat .ai-btn::after{
  content:"";position:absolute;inset:-4px;border-radius:50%;
  background:linear-gradient(135deg,#5b6cff,#ff5b8a);opacity:.4;
  animation:pulse 2.4s ease-out infinite;z-index:-1;
}
@keyframes pulse{0%{transform:scale(1);opacity:.5}100%{transform:scale(1.4);opacity:0}}
#aiChat .ai-panel{
  position:absolute;bottom:70px;right:0;width:320px;max-height:440px;
  background:var(--glass-strong);-webkit-backdrop-filter:blur(34px);backdrop-filter:blur(34px);
  border:1px solid rgba(255,255,255,.7);border-radius:20px;box-shadow:var(--shadow);
  display:none;flex-direction:column;overflow:hidden;
}
#aiChat.open .ai-panel{display:flex}
.ai-head{padding:14px 16px;display:flex;align-items:center;gap:10px;border-bottom:1px solid rgba(0,0,0,.06)}
.ai-head .ai-avatar{width:32px;height:32px;border-radius:50%;background:linear-gradient(135deg,#5b6cff,#ff5b8a);display:grid;place-items:center;color:#fff;font-size:14px;font-weight:700}
.ai-head .ai-info{flex:1}
.ai-head .ai-info b{font-size:14px;display:block}
.ai-head .ai-info span{font-size:12px;color:var(--accent-3)}
.ai-head .ai-info span::before{content:"●";margin-right:4px}
.ai-head .ai-close{background:none;border:0;font-size:20px;cursor:pointer;color:var(--ink-3)}
.ai-body{flex:1;padding:14px;overflow-y:auto;display:flex;flex-direction:column;gap:10px;font-size:13.5px}
.ai-msg{padding:9px 13px;border-radius:14px;max-width:85%;line-height:1.5}
.ai-msg.bot{background:#fff;align-self:flex-start;border-bottom-left-radius:4px}
.ai-msg.me{background:var(--ink);color:#fff;align-self:flex-end;border-bottom-right-radius:4px}
.ai-input{padding:10px;border-top:1px solid rgba(0,0,0,.06);display:flex;gap:8px}
.ai-input input{flex:1;padding:9px 14px;border:1px solid rgba(0,0,0,.08);border-radius:999px;font-size:13px;outline:0;background:rgba(255,255,255,.7)}
.ai-input input:focus{border-color:var(--accent)}
.ai-input button{padding:0 14px;border-radius:999px;background:var(--ink);color:#fff;border:0;cursor:pointer;font-size:13px}

/* ===== Detail page ===== */
.detail-wrap{display:grid;grid-template-columns:1.1fr 1fr;gap:36px;padding:30px 0}
@media(max-width:880px){.detail-wrap{grid-template-columns:1fr}}
.detail-img{border-radius:var(--radius);overflow:hidden;aspect-ratio:4/3;box-shadow:var(--shadow-soft)}
.detail-img img{width:100%;height:100%;object-fit:cover}
.detail-info h1{font-size:30px;letter-spacing:-.01em;margin-bottom:10px}
.detail-info .badge{display:inline-block;padding:4px 12px;border-radius:999px;background:rgba(91,108,255,.12);color:var(--accent);font-size:12.5px;margin-bottom:14px;font-weight:600}
.detail-info .price-box{padding:18px;border-radius:var(--radius-sm);background:rgba(255,255,255,.7);margin:18px 0;display:flex;align-items:baseline;gap:14px}
.detail-info .price-box .now{font-size:34px;font-weight:800;color:var(--accent-2)}
.detail-info .price-box .was{text-decoration:line-through;color:var(--ink-3);font-size:15px}
.detail-info ul.feat-list{list-style:none;margin:14px 0}
.detail-info ul.feat-list li{padding:6px 0 6px 24px;position:relative;color:var(--ink-2);font-size:14.5px}
.detail-info ul.feat-list li::before{content:"✓";position:absolute;left:0;color:var(--accent-3);font-weight:800}

.detail-section{padding:30px 0}
.detail-section h3{margin-bottom:14px;font-size:20px}
.detail-section p{color:var(--ink-2);margin-bottom:10px}

/* ===== Order page ===== */
.order-wrap{display:grid;grid-template-columns:1.2fr 1fr;gap:28px;padding:30px 0}
@media(max-width:880px){.order-wrap{grid-template-columns:1fr}}
.form-card{padding:28px;border-radius:var(--radius)}
.form-card h2{font-size:22px;margin-bottom:18px}
.field{margin-bottom:14px}
.field label{display:block;font-size:13px;color:var(--ink-2);font-weight:600;margin-bottom:6px}
.field input,.field select,.field textarea{
  width:100%;padding:11px 14px;border:1px solid rgba(0,0,0,.1);border-radius:12px;
  font-size:14px;background:rgba(255,255,255,.7);outline:0;font-family:inherit;
}
.field input:focus,.field select:focus,.field textarea:focus{border-color:var(--accent);background:#fff}
.row-2{display:grid;grid-template-columns:1fr 1fr;gap:12px}
@media(max-width:520px){.row-2{grid-template-columns:1fr}}
.summary{padding:24px;border-radius:var(--radius);position:sticky;top:96px;height:fit-content}
.summary h3{font-size:18px;margin-bottom:14px;padding-bottom:14px;border-bottom:1px solid rgba(0,0,0,.06)}
.sum-item{display:flex;justify-content:space-between;padding:8px 0;font-size:14px;color:var(--ink-2)}
.sum-item.total{padding-top:14px;margin-top:8px;border-top:1px solid rgba(0,0,0,.06);font-size:17px;font-weight:700;color:var(--ink)}
.sum-item.total span:last-child{color:var(--accent-2)}
.pay-methods{display:grid;grid-template-columns:1fr 1fr 1fr;gap:8px;margin:12px 0}
.pay-method{
  padding:10px;border:1px solid rgba(0,0,0,.1);border-radius:12px;text-align:center;cursor:pointer;
  font-size:12.5px;background:rgba(255,255,255,.7);transition:.15s;
}
.pay-method.active{border-color:var(--accent);background:rgba(91,108,255,.06);color:var(--accent);font-weight:600}
.btn-buy{width:100%;padding:14px;border-radius:14px;background:var(--ink);color:#fff;border:0;font-size:15px;font-weight:600;cursor:pointer;margin-top:10px}
.btn-buy:hover{background:#000}

/* ===== Generic page ===== */
.page-hero{padding:50px 0 20px;text-align:center}
.page-hero h1{font-size:clamp(28px,4vw,42px);font-weight:800;letter-spacing:-.01em;margin-bottom:12px}
.page-hero p{color:var(--ink-3);max-width:580px;margin:0 auto}
.prose{max-width:780px;margin:0 auto;padding:30px 0}
.prose h2{font-size:22px;margin:26px 0 12px}
.prose p{margin-bottom:12px;color:var(--ink-2);font-size:15px}
.prose ul{padding-left:20px;margin-bottom:12px}
.prose ul li{margin-bottom:6px;color:var(--ink-2)}

/* contact */
.contact-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:18px;margin:30px 0}
@media(max-width:780px){.contact-grid{grid-template-columns:1fr}}
.contact-card{padding:24px;border-radius:var(--radius);text-align:center}
.contact-card .ico{width:46px;height:46px;border-radius:14px;background:linear-gradient(135deg,#5b6cff,#ff5b8a);color:#fff;display:grid;place-items:center;margin:0 auto 12px;font-size:20px}
.contact-card h4{margin-bottom:6px}
.contact-card p{color:var(--ink-3);font-size:13.5px}