/* ============================================================
   bf-binance.com — Vercel-style skin (black & white minimal)
   Palette: #fff / #000 / #eaeaea (line) / #666 #888 (muted)
   ============================================================ */
:root{
  --bg:#ffffff;
  --bg-dark:#000000;
  --fg:#000000;
  --fg-inv:#ffffff;
  --muted:#666666;
  --muted-2:#888888;
  --line:#eaeaea;
  --line-dark:#333333;
  --panel:#fafafa;
  --panel-dark:#0a0a0a;
  --radius:8px;
  --radius-sm:6px;
  --wrap:1100px;
  --font:-apple-system,BlinkMacSystemFont,"Segoe UI",Inter,Roboto,"Helvetica Neue","PingFang SC","Microsoft YaHei",Arial,sans-serif;
  --mono:"SFMono-Regular",ui-monospace,Menlo,Consolas,"Liberation Mono",monospace;
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{
  margin:0;
  background:var(--bg);
  color:var(--fg);
  font-family:var(--font);
  font-size:16px;
  line-height:1.6;
  -webkit-font-smoothing:antialiased;
  overflow-x:hidden;
}
a{color:inherit;text-decoration:none}
img,svg{display:block;max-width:100%}
h1,h2,h3,h4,p{margin:0}
ul{margin:0;padding:0;list-style:none}

.wrap{width:100%;max-width:var(--wrap);margin:0 auto;padding:0 24px}
.wrap.narrow{max-width:760px}

/* ---------- Buttons (vercel: small radius solid black / bordered) ---------- */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:8px;
  height:40px;padding:0 16px;
  border-radius:var(--radius-sm);
  border:1px solid transparent;
  font-size:14px;font-weight:500;line-height:1;
  cursor:pointer;white-space:nowrap;
  transition:background .15s ease,border-color .15s ease,color .15s ease,opacity .15s ease;
  font-family:inherit;
}
.btn-solid{background:#000;color:#fff;border-color:#000}
.btn-solid:hover{background:#383838;border-color:#383838}
.btn-ghost{background:#fff;color:#000;border-color:var(--line)}
.btn-ghost:hover{border-color:#000}
.btn-lg{height:48px;padding:0 22px;font-size:15px}
.btn-block{width:100%}
/* inverted variants on dark sections */
.on-dark .btn-solid{background:#fff;color:#000;border-color:#fff}
.on-dark .btn-solid:hover{background:#e3e3e3;border-color:#e3e3e3}
.on-dark .btn-ghost{background:transparent;color:#fff;border-color:var(--line-dark)}
.on-dark .btn-ghost:hover{border-color:#fff}

/* ---------- Sticky nav (left logo + center menu + right CTA) ---------- */
.nav{
  position:sticky;top:0;z-index:50;
  background:rgba(255,255,255,.8);
  backdrop-filter:saturate(180%) blur(12px);
  -webkit-backdrop-filter:saturate(180%) blur(12px);
  border-bottom:1px solid var(--line);
}
.nav-inner{display:flex;align-items:center;height:64px;gap:24px}
.brand{display:flex;align-items:center;flex:0 0 auto}
.brand img{height:22px;width:auto}
.nav-links{display:flex;align-items:center;gap:26px;flex:1 1 auto}
.nav-links a{font-size:14px;color:#666;font-weight:400}
.nav-links a:hover{color:#000}
.nav-cta{display:flex;align-items:center;gap:10px;flex:0 0 auto}
.nav-cta .btn{height:36px}

/* ---------- Hero (centered huge headline + visual) ---------- */
.hero{padding:88px 0 64px;text-align:center;border-bottom:1px solid var(--line)}
.hero-inner{display:flex;flex-direction:column;align-items:center}
.eyebrow{
  display:inline-flex;align-items:center;gap:8px;
  font-size:13px;color:#666;
  border:1px solid var(--line);border-radius:999px;
  padding:5px 14px;margin-bottom:28px;
}
.eyebrow::before{content:"";width:6px;height:6px;border-radius:50%;background:#000;display:inline-block}
h1{
  font-size:clamp(40px,7vw,80px);
  line-height:1.04;
  letter-spacing:-.04em;
  font-weight:700;
  max-width:14ch;
  margin:0 auto;
}
.hero .lede{
  margin:24px auto 0;max-width:600px;
  font-size:18px;color:#666;line-height:1.6;
}
.hero-actions{display:flex;flex-wrap:wrap;gap:12px;justify-content:center;margin-top:32px}

/* hero gradient mesh visual (replaces vercel triangle render) */
.hero-visual{
  width:100%;max-width:920px;margin:56px auto 0;
  aspect-ratio:920/360;
  border:1px solid var(--line);border-radius:12px;
  overflow:hidden;position:relative;background:#000;
}
.hero-visual svg{width:100%;height:100%;display:block}

/* hero stat row under visual */
.stat-row{
  display:grid;grid-template-columns:repeat(4,1fr);
  width:100%;max-width:920px;margin:40px auto 0;
  border:1px solid var(--line);border-radius:12px;overflow:hidden;
}
.stat-row li{
  padding:24px 16px;text-align:center;
  border-right:1px solid var(--line);
}
.stat-row li:last-child{border-right:none}
.stat-row strong{display:block;font-size:30px;font-weight:700;letter-spacing:-.02em}
.stat-row span{display:block;margin-top:6px;font-size:13px;color:#666}

/* ---------- Logo / proof strip ---------- */
.proof{padding:36px 0;border-bottom:1px solid var(--line)}
.proof-inner{
  display:flex;align-items:center;justify-content:center;
  flex-wrap:wrap;gap:14px 28px;
  font-size:15px;color:#666;text-align:center;
}
.proof-inner b{color:#000;font-weight:600}
.proof-tags{display:flex;flex-wrap:wrap;gap:10px;justify-content:center}
.proof-tags span{
  border:1px solid var(--line);border-radius:999px;
  padding:6px 14px;font-size:13px;color:#000;
}

/* ---------- Generic band / section ---------- */
.band{padding:80px 0;border-bottom:1px solid var(--line)}
.kicker{font-size:13px;color:#666;font-weight:500;margin-bottom:12px}
.band h2{
  font-size:clamp(28px,4vw,40px);line-height:1.1;
  letter-spacing:-.03em;font-weight:700;max-width:18ch;
}
.band-lede{margin-top:16px;max-width:560px;color:#666;font-size:17px}
.sec-head{margin-bottom:40px}

/* feature trio (3 short columns, vercel "Your product, delivered") */
.trio{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:1px;background:var(--line);
  border:1px solid var(--line);border-radius:12px;overflow:hidden}
.trio > div{background:#fff;padding:28px 24px}
.trio h3{font-size:18px;font-weight:600;letter-spacing:-.01em}
.trio p{margin-top:8px;color:#666;font-size:14px}

/* grid utilities */
.grid{display:grid;gap:16px}
.grid-3{grid-template-columns:repeat(3,minmax(0,1fr))}
.grid-4{grid-template-columns:repeat(4,minmax(0,1fr))}

/* feature cards (icon + heading + text, thin border) */
.card{
  border:1px solid var(--line);border-radius:12px;padding:28px 24px;background:#fff;
  transition:border-color .15s ease;
}
.card:hover{border-color:#000}
.card .ic{
  width:44px;height:44px;border:1px solid var(--line);border-radius:10px;
  display:flex;align-items:center;justify-content:center;margin-bottom:18px;
}
.card h3{font-size:18px;font-weight:600;letter-spacing:-.01em}
.card p{margin-top:10px;color:#666;font-size:14px}

/* platform cards (download) */
.plat{
  border:1px solid var(--line);border-radius:12px;padding:24px;background:#fff;
  display:flex;flex-direction:column;gap:8px;
}
.plat .ic{width:36px;height:36px;margin-bottom:6px}
.plat h3{font-size:17px;font-weight:600}
.plat p{color:#666;font-size:14px;flex:1 1 auto}
.plat .btn{margin-top:14px}

/* split block: heading left + visual right (scale out) */
.split{display:grid;grid-template-columns:1fr 1fr;gap:48px;align-items:center}
.split .split-visual{
  border:1px solid var(--line);border-radius:12px;overflow:hidden;background:var(--panel);
  aspect-ratio:5/4;
}
.split .split-visual svg{width:100%;height:100%}
.split h2{max-width:14ch}
.split-actions{display:flex;flex-wrap:wrap;gap:12px;margin-top:28px}

/* ---------- Dark showcase band ---------- */
.dark{background:#000;color:#fff;padding:96px 0;border-bottom:1px solid #000}
.dark .kicker{color:#888}
.dark h2{color:#fff}
.dark .band-lede{color:#a1a1a1}
.dark .show-visual{
  width:100%;max-width:760px;margin:40px auto 0;
  border:1px solid var(--line-dark);border-radius:12px;overflow:hidden;background:#0a0a0a;
  aspect-ratio:760/300;
}
.dark .show-visual svg{width:100%;height:100%}
.dark.center{text-align:center}
.dark.center h2{margin:0 auto}

/* ---------- Code / dev split block ---------- */
.codeblk{display:grid;grid-template-columns:1fr 1fr;gap:48px;align-items:start}
.code-panel{
  background:#000;border:1px solid var(--line-dark);border-radius:12px;overflow:hidden;
}
.code-bar{display:flex;align-items:center;gap:6px;padding:12px 14px;border-bottom:1px solid var(--line-dark)}
.code-bar i{width:11px;height:11px;border-radius:50%;background:#333;display:block}
.code-body{padding:18px;font-family:var(--mono);font-size:13px;line-height:1.7;color:#e3e3e3;overflow-x:auto}
.code-body .c1{color:#888}
.code-body .c2{color:#9cdcfe}
.code-body .c3{color:#c586c0}
.quote-list{display:flex;flex-direction:column}
.quote-list .qrow{
  display:flex;align-items:center;justify-content:space-between;
  padding:14px 4px;border-bottom:1px solid var(--line);font-size:14px;
}
.quote-list .qrow:first-child{border-top:1px solid var(--line)}
.quote-list .qrow .sym{display:flex;align-items:center;gap:10px;font-weight:600}
.quote-list .qrow .sym small{color:#666;font-weight:400}
.quote-list .qrow .val{font-variant-numeric:tabular-nums;color:#000}
.quote-list .qrow .chg{font-variant-numeric:tabular-nums;width:74px;text-align:right}
.chg.up{color:#0a7d28}
.chg.down{color:#c11414}
.dot{width:22px;height:22px;border:1px solid var(--line);border-radius:6px;display:inline-flex;align-items:center;justify-content:center;font-size:11px;color:#666}

/* ---------- Card grid (templates / steps) ---------- */
.tiles{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:16px}
.tile{
  border:1px solid var(--line);border-radius:12px;padding:22px;background:#fff;
  display:flex;flex-direction:column;gap:10px;transition:border-color .15s ease;
}
.tile:hover{border-color:#000}
.tile .tile-top{display:flex;align-items:center;gap:12px}
.tile .badge{
  width:40px;height:40px;border-radius:8px;display:flex;align-items:center;justify-content:center;
  border:1px solid var(--line);font-weight:700;font-size:14px;
}
.tile h3{font-size:16px;font-weight:600}
.tile p{color:#666;font-size:14px}

/* ---------- FAQ (details) ---------- */
.faq-list details{border-bottom:1px solid var(--line);padding:4px 0}
.faq-list summary{
  list-style:none;cursor:pointer;padding:18px 0;
  font-size:17px;font-weight:500;display:flex;justify-content:space-between;align-items:center;gap:16px;
}
.faq-list summary::-webkit-details-marker{display:none}
.faq-list summary::after{content:"+";font-size:22px;color:#666;font-weight:400;line-height:1}
.faq-list details[open] summary::after{content:"–"}
.faq-list details p{padding:0 0 20px;color:#666;font-size:15px}

/* ---------- Big final CTA ---------- */
.cta-final{padding:120px 0;text-align:center;border-bottom:1px solid var(--line)}
.cta-final h2{
  font-size:clamp(40px,6vw,68px);line-height:1.05;letter-spacing:-.04em;font-weight:700;
  max-width:16ch;margin:0 auto;
}
.cta-final p{margin:20px auto 0;max-width:480px;color:#666;font-size:17px}
.cta-final .hero-actions{margin-top:32px}

/* ---------- Footer (multi-column + bottom status row) ---------- */
.foot{padding:64px 0 0;background:#fff}
.foot-inner{
  display:grid;grid-template-columns:1.4fr 1fr 1fr 1fr;gap:40px;
  padding-bottom:56px;border-bottom:1px solid var(--line);
}
.foot-brand img{height:22px;margin-bottom:16px}
.foot-brand p{color:#666;font-size:14px;max-width:30ch}
.foot-col h4{font-size:13px;color:#000;font-weight:600;margin-bottom:14px}
.foot-col a{display:block;color:#666;font-size:14px;padding:5px 0}
.foot-col a:hover{color:#000}
.foot-bottom{
  display:flex;align-items:center;justify-content:space-between;gap:16px;flex-wrap:wrap;
  padding:24px 0 48px;
}
.foot-bottom .status{display:flex;align-items:center;gap:8px;font-size:13px;color:#666}
.foot-bottom .status::before{content:"";width:8px;height:8px;border-radius:50%;background:#0a7d28;display:inline-block}
.foot-bottom .copy{font-size:13px;color:#888}
.foot-risk{padding:20px 0;border-top:1px solid var(--line)}
.foot-risk p{font-size:12px;color:#888;line-height:1.6}

/* ============================================================
   Responsive — mobile single column, 390px safe
   ============================================================ */
@media (max-width:900px){
  .split,.codeblk{grid-template-columns:1fr;gap:32px}
  .grid-4{grid-template-columns:repeat(2,minmax(0,1fr))}
  .tiles{grid-template-columns:repeat(2,minmax(0,1fr))}
  .foot-inner{grid-template-columns:1fr 1fr;gap:32px}
}
@media (max-width:640px){
  .wrap{padding:0 20px}
  .nav-inner{height:56px;gap:12px}
  .nav-links{display:none}
  .hero{padding:56px 0 40px}
  h1{font-size:clamp(34px,10vw,46px);max-width:none}
  .hero .lede{font-size:16px}
  .band{padding:56px 0}
  .dark{padding:64px 0}
  .cta-final{padding:80px 0}
  .trio,.grid-3,.grid-4,.tiles{grid-template-columns:1fr}
  .stat-row{grid-template-columns:repeat(2,1fr)}
  .stat-row li:nth-child(2){border-right:none}
  .stat-row li:nth-child(1),.stat-row li:nth-child(2){border-bottom:1px solid var(--line)}
  .hero-actions .btn,.cta-final .hero-actions .btn{width:100%}
  .foot-inner{grid-template-columns:1fr 1fr;gap:28px}
  .foot-bottom{flex-direction:column;align-items:flex-start}
  .band h2,.cta-final h2,h1,.split h2{max-width:none}
}
@media (max-width:380px){
  .stat-row{grid-template-columns:1fr}
  .stat-row li{border-right:none;border-bottom:1px solid var(--line)}
  .stat-row li:last-child{border-bottom:none}
}