:root{
  --bg:#eff6ff; --ink:#1e293b; --muted:#64748b;
  --accent:#3b82f6; --accent2:#93c5fd;
  --line:#dbeafe; --card:#ffffff;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--ink);font-family:"PingFang SC","Microsoft YaHei",-apple-system,BlinkMacSystemFont,sans-serif;line-height:1.75;position:relative;overflow-x:hidden}
.container{max-width:1040px;margin:0 auto;padding:0 24px}
a{color:inherit;text-decoration:none}
h1,h2,h3{margin:0 0 12px;font-weight:800}
p{margin:0 0 12px;color:var(--muted)}

/* floating clouds background */
.clouds{position:fixed;inset:0;z-index:-1;overflow:hidden}
.clouds span{position:absolute;background:#fff;border-radius:50%;opacity:.6;filter:blur(2px);animation:drift linear infinite}
.clouds span::before,.clouds span::after{content:"";position:absolute;background:#fff;border-radius:50%}
.c1{width:120px;height:44px;top:10%;left:-140px;animation-duration:38s}
.c1::before{width:70px;height:70px;top:-34px;left:14px}
.c1::after{width:50px;height:50px;top:-22px;left:64px}
.c2{width:90px;height:34px;top:28%;left:-120px;animation-duration:50s;animation-delay:-10s}
.c2::before{width:52px;height:52px;top:-26px;left:10px}
.c2::after{width:36px;height:36px;top:-16px;left:48px}
.c3{width:100px;height:38px;top:55%;left:-130px;animation-duration:44s;animation-delay:-22s}
.c3::before{width:58px;height:58px;top:-28px;left:12px}
.c3::after{width:40px;height:40px;top:-18px;left:54px}
@keyframes drift{from{transform:translateX(0)}to{transform:translateX(calc(100vw + 200px))}}

.site-nav{position:sticky;top:0;z-index:50;backdrop-filter:blur(10px);background:rgba(239,246,255,.85);border-bottom:1px solid var(--line)}
.nav-inner{max-width:1040px;margin:0 auto;padding:16px 24px;display:flex;align-items:center;justify-content:space-between}
.brand{display:flex;align-items:center;gap:8px;font-weight:800;font-size:18px}
.brand svg{width:26px;height:26px}
.brand-en{color:var(--muted);font-weight:500;font-size:12px}
.nav-links{display:flex;gap:24px}
.nav-links a{color:var(--muted);font-size:14px}
.nav-links a:hover{color:var(--accent)}
.nav-actions{display:flex;align-items:center;gap:10px}
.burger{display:none;flex-direction:column;gap:4px;cursor:pointer}
.burger span{width:22px;height:2px;background:var(--ink)}
#nav-toggle,.mobile-menu{display:none}

.btn{display:inline-flex;align-items:center;justify-content:center;padding:11px 24px;border-radius:999px;font-size:14px;font-weight:700;transition:.25s;border:1px solid transparent;cursor:pointer}
.btn-primary{background:var(--accent);color:#fff;box-shadow:0 10px 24px -10px rgba(59,130,246,.6)}
.btn-primary:hover{background:#2563eb}
.btn-ghost{border-color:var(--line);color:var(--ink);background:#fff}
.btn-ghost:hover{background:var(--card)}
.btn-block{width:100%}

.hero{padding:110px 0 70px;text-align:center}
.promo-tag{display:inline-block;padding:6px 16px;border-radius:999px;background:#fff;border:1px solid var(--line);font-size:13px;color:var(--accent);margin-bottom:22px}
.hero h1{font-size:42px;line-height:1.35;max-width:740px;margin:0 auto 18px}
.hero h1 span{color:var(--accent)}
.hero .sub{max-width:540px;margin:0 auto 28px}
.hero-ctas{display:flex;gap:14px;justify-content:center;flex-wrap:wrap}

section{padding:64px 0}
.section-head{text-align:center;max-width:560px;margin:0 auto 42px}
.eyebrow{display:inline-block;font-size:12px;letter-spacing:.14em;color:var(--accent);margin-bottom:8px}

/* vertical timeline for advantages */
.timeline{position:relative;max-width:680px;margin:0 auto;padding-left:34px}
.timeline::before{content:"";position:absolute;left:9px;top:6px;bottom:6px;width:2px;background:var(--line)}
.tl-item{position:relative;padding-bottom:30px}
.tl-item:last-child{padding-bottom:0}
.tl-item::before{content:"";position:absolute;left:-34px;top:4px;width:20px;height:20px;border-radius:50%;background:var(--accent);border:4px solid var(--bg)}
.tl-item h3{margin-bottom:4px}

.stream-row{margin-top:32px;background:var(--card);border:1px solid var(--line);border-radius:16px;padding:20px 24px;display:flex;flex-wrap:wrap;gap:14px;align-items:center;justify-content:space-between;max-width:680px;margin-left:auto;margin-right:auto}
.pill-list{display:flex;flex-wrap:wrap;gap:8px}
.pill{padding:6px 14px;border-radius:999px;background:rgba(59,130,246,.1);color:var(--accent);font-size:13px}

/* tab-toggle pricing (CSS radio trick) */
.tabs{max-width:640px;margin:0 auto}
.tab-nav{display:flex;gap:8px;background:#fff;border:1px solid var(--line);border-radius:999px;padding:6px;margin-bottom:24px}
.tab-nav label{flex:1;text-align:center;padding:10px;border-radius:999px;font-size:14px;font-weight:700;cursor:pointer;color:var(--muted);transition:.2s}
#tab1:checked ~ .tab-nav label[for="tab1"],
#tab2:checked ~ .tab-nav label[for="tab2"],
#tab3:checked ~ .tab-nav label[for="tab3"]{background:var(--accent);color:#fff}
.tab-panels{position:relative}
.tab-panel{display:none;background:var(--card);border:1px solid var(--line);border-radius:16px;padding:32px;text-align:center}
#tab1:checked ~ .tab-panels .panel1,
#tab2:checked ~ .tab-panels .panel2,
#tab3:checked ~ .tab-panels .panel3{display:block}
.tab-panel .cap{color:var(--muted);font-size:13px;margin-bottom:10px}
.tab-panel .now{font-size:34px;font-weight:900;color:var(--ink);display:block;margin-bottom:6px}
.tab-panel .period{color:var(--muted);font-size:13px;margin-bottom:22px;display:block}
input[name="pricetab"]{display:none}
.price-note{font-size:12px;color:var(--muted);text-align:center;margin-top:16px}

/* checklist for why-choose instead of data panels */
.checklist{max-width:640px;margin:0 auto;display:flex;flex-direction:column;gap:18px}
.check-item{display:flex;gap:14px;align-items:flex-start;background:var(--card);border:1px solid var(--line);border-radius:12px;padding:18px 20px}
.check-item .mark{flex-shrink:0;width:28px;height:28px;border-radius:50%;background:var(--accent);color:#fff;display:flex;align-items:center;justify-content:center;font-size:14px}
.check-item h3{margin-bottom:4px;font-size:16px}
.check-item p{margin:0}

.cta-band{text-align:center;background:linear-gradient(135deg,var(--accent),#60a5fa);border-radius:24px;padding:56px 24px;color:#fff}
.cta-band h2{color:#fff}
.cta-band p{color:#dbeafe}
.cta-band .btn-primary{background:#fff;color:var(--accent)}
.cta-band .btn-primary:hover{background:#f0f7ff}

/* single rotating quote carousel (CSS radio trick) */
.quote-carousel{max-width:640px;margin:0 auto;text-align:center;position:relative}
input[name="qtab"]{display:none}
.q-slide{display:none;background:var(--card);border:1px solid var(--line);border-radius:16px;padding:36px}
#q1:checked ~ .q-slides .qs1,
#q2:checked ~ .q-slides .qs2,
#q3:checked ~ .q-slides .qs3,
#q4:checked ~ .q-slides .qs4{display:block}
.q-slide .stars{color:#f59e0b;font-size:16px;margin-bottom:14px}
.q-slide p{font-size:16px;color:var(--ink);margin-bottom:14px}
.q-slide .t-name{font-weight:700;font-size:13px;color:var(--muted)}
.q-dots{display:flex;gap:8px;justify-content:center;margin-top:18px}
.q-dots label{width:9px;height:9px;border-radius:50%;background:var(--line);cursor:pointer}
#q1:checked ~ .q-dots label[for="q1"],
#q2:checked ~ .q-dots label[for="q2"],
#q3:checked ~ .q-dots label[for="q3"],
#q4:checked ~ .q-dots label[for="q4"]{background:var(--accent)}

.faq-list{max-width:680px;margin:0 auto}
.faq-item{background:var(--card);border:1px solid var(--line);border-radius:12px;padding:16px 20px;margin-bottom:10px}
.faq-item summary{cursor:pointer;font-weight:700;list-style:none;display:flex;justify-content:space-between;align-items:center}
.faq-item summary::-webkit-details-marker{display:none}
.faq-item summary::after{content:"⌄";font-size:18px;color:var(--accent);transition:.2s}
.faq-item[open] summary::after{transform:rotate(180deg)}
.faq-item p{margin-top:10px}

footer{border-top:1px solid var(--line);padding:48px 0 26px;margin-top:20px}
.footer-grid{display:grid;grid-template-columns:2fr 1fr 1fr;gap:28px;margin-bottom:28px}
.footer-col h4{font-size:14px;margin-bottom:12px}
.footer-col ul{list-style:none;padding:0;margin:0;display:flex;flex-direction:column;gap:8px}
.footer-col ul a{color:var(--muted);font-size:13px}
.footer-col ul a:hover{color:var(--accent)}
.footer-seo{font-size:12px;color:var(--muted);max-width:900px}
.friend-links{display:flex;flex-wrap:wrap;gap:10px;margin:16px 0;font-size:12px}
.friend-links .label{color:var(--muted)}
.friend-links a{color:var(--muted);padding:2px 10px;border:1px solid var(--line);border-radius:999px;background:#fff}
.friend-links a:hover{color:var(--accent);border-color:var(--accent)}
.copyright{font-size:12px;color:var(--muted)}

@media (max-width:860px){
  .footer-grid{grid-template-columns:1fr}
  .nav-links{display:none}
  .burger{display:flex}
  .nav-actions .btn-ghost{display:none}
  #nav-toggle:checked ~ .mobile-menu{display:flex}
  .mobile-menu{display:none;position:absolute;top:100%;left:0;right:0;background:var(--bg);flex-direction:column;padding:20px 24px;gap:14px;border-bottom:1px solid var(--line)}
  .hero h1{font-size:28px}
  .timeline{padding-left:28px}
  .tab-nav label{font-size:12px;padding:8px 4px}
}