/* ============================================================
   B4BET — Apple product-page + Bento grid theme
   EDIT GUIDE / 修改指南：
   · 改颜色：只改下面 :root 里的令牌（--ink/--blue/--gold/--bg）
     全站共用，改一处处处生效，不要在正文里写死色值。
   · 改圆角/间距：--r / --r-lg / --gap；改动效：--dur / --ease。
   · 版式分段：masthead / bento / tile / panel / calc / vote /
     checkin / countdown / info / cta-band / footer / tabbar，
     段前都有注释。
   ============================================================ */
:root{
  --bg:#F2F6FF; --ink:#0A1B3D; --mut:#3D4E73; --dim:#5B6B8C;
  --blue:#0B4DFF; --blue-deep:#0A2A8F; --blue-soft:#DCE6FB; --blue-pale:#EAF1FF;
  --gold:#7A5F00; --gold-bright:#F5B301; --line:#D8E2F7; --card:#FFFFFF;
  --r:18px; --r-lg:26px; --gap:16px; --dur:.45s; --ease:cubic-bezier(.22,.9,.3,1);
  --shadow:0 10px 30px rgba(10,42,143,.10);
}
*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth}
body{font-family:-apple-system,BlinkMacSystemFont,"SF Pro Display","Segoe UI",Roboto,"PingFang SC","Microsoft YaHei",sans-serif;background:var(--bg);color:var(--ink);line-height:1.65;font-size:17px;-webkit-font-smoothing:antialiased}
img{max-width:100%;display:block}
a{color:var(--blue);text-decoration:none}
a:hover{text-decoration:underline}
.wrap{max-width:1180px;margin:0 auto;padding:0 22px}
h1{font-size:clamp(34px,5vw,56px);line-height:1.08;letter-spacing:-.02em;font-weight:800}
h2{font-size:clamp(24px,3.4vw,34px);line-height:1.2;letter-spacing:-.015em;font-weight:750}
h3{font-size:20px;line-height:1.35;font-weight:700}
.kicker{font-size:13px;font-weight:700;letter-spacing:.14em;text-transform:uppercase;color:var(--blue)}
.lede{font-size:19px;color:var(--mut);max-width:720px}
.num{font-variant-numeric:tabular-nums}
.gold{color:var(--gold);font-weight:800}
.blue{color:var(--blue)}
/* ---------- masthead ---------- */
.topbar{background:var(--blue-deep);color:#fff;font-size:13px}
.topbar .wrap{display:flex;justify-content:space-between;gap:12px;padding-top:6px;padding-bottom:6px}
.mast{position:sticky;top:0;z-index:50;background:rgba(255,255,255,.92);backdrop-filter:blur(14px);-webkit-backdrop-filter:blur(14px);border-bottom:1px solid var(--line)}
.mast-in{display:flex;align-items:center;gap:18px;max-width:1180px;margin:0 auto;padding:10px 22px}
.logo img{height:34px;width:auto}
.nav{display:flex;gap:6px;margin-left:8px}
.nav a{color:var(--ink);font-size:15px;font-weight:600;padding:8px 13px;border-radius:999px;white-space:nowrap}
.nav a:hover{background:var(--blue-pale);text-decoration:none}
.nav a.on{background:var(--blue);color:#fff}
.mast-right{margin-left:auto;display:flex;align-items:center;gap:10px}
.langseg{display:flex;border:1px solid var(--line);border-radius:999px;overflow:hidden;background:#fff}
.langseg button{border:0;background:transparent;font:inherit;font-size:14px;font-weight:600;padding:8px 12px;cursor:pointer;color:var(--mut);min-height:36px}
.langseg button.on{background:var(--blue);color:#fff}
.btn{display:inline-flex;align-items:center;justify-content:center;min-height:44px;padding:10px 20px;border-radius:999px;font-size:15px;font-weight:700;border:1.5px solid var(--blue);cursor:pointer;white-space:nowrap}
.btn-line{background:#fff;color:var(--blue)}
.btn-solid{background:var(--blue);color:#fff;border-color:var(--blue)}
.btn:active{transform:scale(.97)}
/* ---------- hero / bento ---------- */
.hero{padding:44px 0 10px}
.hero h1{margin:12px 0 14px}
.bento{display:grid;grid-template-columns:repeat(12,1fr);gap:var(--gap);margin:26px 0}
.tile{position:relative;border-radius:var(--r-lg);overflow:hidden;background:var(--card);box-shadow:var(--shadow);min-height:200px;display:flex;flex-direction:column;justify-content:flex-end}
.tile img.bg{position:absolute;inset:0;width:100%;height:100%;object-fit:cover}
.tile .shade{position:absolute;inset:0;background:linear-gradient(180deg,rgba(10,27,61,0) 30%,rgba(10,27,61,.82) 100%)}
.tile .txt{position:relative;padding:22px;color:#fff}
.tile .txt h3{font-size:23px;line-height:1.25}
.tile .txt p{font-size:15px;color:rgba(255,255,255,.88);margin-top:6px}
.tile .tag{display:inline-block;font-size:12px;font-weight:800;letter-spacing:.1em;text-transform:uppercase;background:rgba(255,255,255,.92);color:var(--blue-deep);padding:5px 11px;border-radius:999px;margin-bottom:10px}
.tile.plain{justify-content:flex-start;padding:24px;color:var(--ink)}
.tile.plain h3{color:var(--ink)}
.tile.plain p{color:var(--mut);font-size:15px;margin-top:6px}
.span8{grid-column:span 8}.span6{grid-column:span 6}.span4{grid-column:span 4}.span3{grid-column:span 3}
.row2{grid-row:span 2}
.stat{background:var(--card);border-radius:var(--r-lg);box-shadow:var(--shadow);padding:22px 24px;display:flex;flex-direction:column;gap:4px;justify-content:center}
.stat b{font-size:clamp(30px,3.6vw,42px);letter-spacing:-.02em;color:var(--blue);line-height:1.05}
.stat span{font-size:14px;color:var(--mut);font-weight:600}
/* ---------- sections ---------- */
.sec{padding:34px 0}
.sec h2{margin-bottom:10px}
.figure{border-radius:var(--r-lg);overflow:hidden;box-shadow:var(--shadow);margin:18px 0}
.figure img{width:100%}
.figure figcaption{padding:12px 18px;background:#fff;font-size:14px;color:var(--mut);border-top:1px solid var(--line)}
.panel{background:var(--card);border-radius:var(--r-lg);box-shadow:var(--shadow);padding:26px}
.panel h3{margin-bottom:6px}
.panel p{color:var(--mut);font-size:15.5px}
.prose p{margin-bottom:14px;color:var(--mut);font-size:17px}
.prose p:first-child{color:var(--ink)}
.grid2{display:grid;grid-template-columns:1fr 1fr;gap:var(--gap)}
.grid2 .panel{display:flex;flex-direction:column;gap:8px}
/* ---------- calculator ---------- */
.calc label{display:block;font-size:14px;font-weight:700;color:var(--mut);margin:14px 0 6px}
.calc input[type=range]{width:100%;accent-color:var(--blue);height:32px}
.calc input[type=number]{width:100%;font:inherit;font-size:17px;padding:11px 14px;border:1.5px solid var(--line);border-radius:12px;background:#fff;color:var(--ink)}
.calc .out{display:flex;gap:14px;margin-top:18px;flex-wrap:wrap}
.calc .out div{flex:1;min-width:140px;background:var(--blue-pale);border-radius:14px;padding:14px 16px}
.calc .out span{display:block;font-size:13px;font-weight:700;color:var(--mut)}
.calc .out b{font-size:24px;color:var(--blue-deep)}
.calc .note{font-size:13px;color:var(--dim);margin-top:12px}
/* ---------- vote demo ---------- */
.vote{display:flex;flex-direction:column;gap:10px;margin-top:16px}
.vote button{border:0;cursor:pointer;font:inherit;font-weight:800;font-size:17px;padding:14px 18px;border-radius:14px;color:#fff;min-height:52px}
.vote .va{background:#C8102E}.vote .vb{background:var(--blue)}
.vote button.picked{outline:3px solid var(--ink);outline-offset:2px}
.bar{height:12px;border-radius:999px;background:var(--blue-soft);overflow:hidden}
.bar i{display:block;height:100%;background:linear-gradient(90deg,#C8102E,var(--blue));transition:width var(--dur) var(--ease)}
.vote .demo{font-size:13px;color:var(--dim)}
/* ---------- check-in demo ---------- */
.days{display:grid;grid-template-columns:repeat(7,1fr);gap:10px;margin-top:16px}
.day{border:1.5px solid var(--line);background:#fff;border-radius:14px;padding:12px 6px;text-align:center;cursor:pointer;font:inherit;min-height:64px}
.day b{display:block;font-size:18px}
.day span{font-size:12px;color:var(--mut);font-weight:700}
.day.done{background:var(--blue);border-color:var(--blue);color:#fff}
.day.done span{color:rgba(255,255,255,.85)}
/* ---------- countdown ---------- */
.cd{display:flex;gap:12px;margin-top:14px;flex-wrap:wrap}
.cd div{background:var(--blue-deep);color:#fff;border-radius:14px;padding:12px 16px;min-width:78px;text-align:center}
.cd b{font-size:26px;display:block;line-height:1.1}
.cd span{font-size:12px;font-weight:700;letter-spacing:.06em;text-transform:uppercase;opacity:.85}
/* ---------- info rows / steps ---------- */
.info details{background:var(--card);border-radius:var(--r);box-shadow:var(--shadow);margin-bottom:10px;padding:18px 20px}
.info summary{font-weight:700;font-size:17px;cursor:pointer;list-style:none}
.info summary::-webkit-details-marker{display:none}
.info details p{color:var(--mut);margin-top:8px;font-size:15.5px}
.steps{counter-reset:st;display:flex;flex-direction:column;gap:12px;margin-top:14px}
.steps div{counter-increment:st;background:var(--card);border-radius:var(--r);box-shadow:var(--shadow);padding:18px 20px 18px 64px;position:relative;font-weight:600}
.steps div::before{content:counter(st);position:absolute;left:18px;top:50%;transform:translateY(-50%);width:32px;height:32px;border-radius:50%;background:var(--blue);color:#fff;display:flex;align-items:center;justify-content:center;font-weight:800}
/* ---------- cta / footer / tabbar ---------- */
.cta-band{background:var(--blue-deep);color:#fff;border-radius:var(--r-lg);padding:34px 30px;margin:30px 0;display:flex;gap:20px;align-items:center;flex-wrap:wrap}
.cta-band h2{color:#fff}
.cta-band p{color:rgba(255,255,255,.85);max-width:560px}
.cta-band .btn-solid{background:#fff;color:var(--blue-deep);border-color:#fff}
.cta-band .btn-line{background:transparent;color:#fff;border-color:#fff}
footer{background:#fff;border-top:1px solid var(--line);margin-top:10px}
.foot{display:grid;grid-template-columns:2fr 1fr 1fr;gap:28px;padding:36px 0 24px}
.foot h4{font-size:15px;margin-bottom:12px}
.foot p,.foot a{font-size:14.5px;color:var(--mut)}
.foot ul{list-style:none}
.foot li{margin-bottom:8px}
.foot .award img{border-radius:12px;margin-top:10px;max-width:220px}
.legal{border-top:1px solid var(--line);padding:16px 0 90px;font-size:13.5px;color:var(--dim);display:flex;justify-content:space-between;gap:14px;flex-wrap:wrap}
.tabbar{display:none}
.rv{opacity:1;transform:none;transition:transform var(--dur) var(--ease),opacity var(--dur) var(--ease)}
html.js .rv{opacity:0;transform:translateY(14px)}
html.js .rv.in{opacity:1;transform:none}
@media (prefers-reduced-motion:reduce){.rv{transition:none;opacity:1!important;transform:none!important}}
@media(max-width:1024px){.nav{display:none}.span8,.span6{grid-column:span 12}.span4{grid-column:span 6}.span3{grid-column:span 6}.row2{grid-row:auto}}
@media(max-width:880px){
  .mast-in{flex-wrap:wrap;padding-top:8px;padding-bottom:8px;row-gap:8px}
  .mast-right{margin-left:0;width:100%;justify-content:flex-end;flex-wrap:wrap}
  .grid2{grid-template-columns:1fr}
  .foot{grid-template-columns:1fr 1fr}
  .tabbar{display:flex;position:fixed;left:0;right:0;bottom:0;z-index:60;background:rgba(255,255,255,.96);border-top:1px solid var(--line);padding:6px 4px calc(6px + env(safe-area-inset-bottom))}
  .tabbar a{flex:1;text-align:center;font-size:11.5px;font-weight:700;color:var(--mut);padding:4px 2px}
  .tabbar a.on{color:var(--blue)}
  .tabbar svg{display:block;margin:0 auto 2px;width:22px;height:22px}
}
@media(max-width:560px){
  .span4,.span3{grid-column:span 12}
  .days{grid-template-columns:repeat(4,1fr)}
  .foot{grid-template-columns:1fr}
  body{font-size:16px}
}