/* ============================================================
   QINGNENG V2 — Design System (Dark Industrial Tech)
   ============================================================ */
:root{
  --bg:#070b11;
  --bg-2:#0b121c;
  --bg-3:#0e1622;
  --panel:rgba(255,255,255,.035);
  --panel-2:rgba(255,255,255,.055);
  --line:rgba(255,255,255,.09);
  --line-strong:rgba(255,255,255,.16);
  --text:#eef3f8;
  --text-2:#b9c5d4;
  --muted:#7e8ca0;
  --accent:#3ec5ff;
  --accent-2:#67e8f9;
  --accent-soft:rgba(62,197,255,.12);
  --ok:#5eead4;
  --warn:#fbbf24;
  --danger:#f87171;
  --radius:6px;
  --nav-h:74px;
  --nav-h-scrolled:58px;
  --ease:cubic-bezier(.22,.61,.36,1);
  --font-en:"Inter","SF Pro Display",-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;
  --font-cn:"PingFang SC","Microsoft YaHei","Hiragino Sans GB","Noto Sans SC",-apple-system,sans-serif;
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{
  background:var(--bg);
  color:var(--text);
  font-family:var(--font-en);
  font-size:16px;
  line-height:1.65;
  -webkit-font-smoothing:antialiased;
  overflow-x:hidden;
}
img{display:block;max-width:100%;height:auto}
a{color:inherit;text-decoration:none}
ul{list-style:none}
button{font-family:inherit;cursor:pointer;border:0;background:none;color:inherit}
input,select,textarea{font-family:inherit;font-size:1rem;color:var(--text)}
::selection{background:var(--accent-soft);color:var(--text)}

/* ---------- layout ---------- */
.container{width:min(1200px,100% - 48px);margin-inline:auto}
.section{padding:clamp(84px,10vw,140px) 0;position:relative}
.section--tight{padding:clamp(56px,7vw,96px) 0}
.eyebrow{
  display:inline-flex;align-items:center;gap:10px;
  font-size:.72rem;font-weight:600;letter-spacing:.28em;
  text-transform:uppercase;color:var(--accent);
}
.eyebrow::before{content:"";width:26px;height:1px;background:var(--accent);opacity:.7}
h1,h2,h3{line-height:1.12;letter-spacing:-.02em;font-weight:650}
.h-display{
  font-size:clamp(2.3rem,5.4vw,4.15rem);
  line-height:1.06;font-weight:700;letter-spacing:-.03em;
}
.h-section{
  font-size:clamp(1.75rem,3.6vw,2.7rem);
  font-weight:700;letter-spacing:-.025em;
}
.sec-sub{color:var(--muted);font-size:clamp(1rem,1.4vw,1.15rem);max-width:640px}
.sec-head{margin-bottom:clamp(40px,6vw,72px)}
.sec-head .sec-sub{margin-top:14px}
.zh{font-family:var(--font-cn)}
.zh-badge{
  display:inline-block;font-family:var(--font-cn);
  font-size:.8rem;color:var(--muted);letter-spacing:.1em;margin-top:6px;
}

/* ---------- buttons ---------- */
.btn{
  display:inline-flex;align-items:center;gap:10px;
  padding:13px 26px;font-size:.82rem;font-weight:650;
  letter-spacing:.14em;text-transform:uppercase;
  border:1px solid var(--line-strong);border-radius:var(--radius);
  color:var(--text);background:transparent;
  transition:border-color .25s,color .25s,background .25s,transform .25s;
  white-space:nowrap;
}
.btn:hover{border-color:var(--accent);color:var(--accent)}
.btn--solid{background:var(--accent);border-color:var(--accent);color:#04121d}
.btn--solid:hover{background:var(--accent-2);color:#04121d;border-color:var(--accent-2)}
.btn--ghost{border-color:rgba(255,255,255,.22)}
.btn--ghost:hover{border-color:var(--text);color:var(--text)}
.btn .arr{transition:transform .25s var(--ease)}
.btn:hover .arr{transform:translateX(4px)}
.btn--sm{padding:9px 18px;font-size:.74rem}

/* ---------- nav ---------- */
.nav{
  position:fixed;inset:0 0 auto 0;z-index:100;
  height:var(--nav-h);
  display:flex;align-items:center;
  background:rgba(7,11,17,.55);
  -webkit-backdrop-filter:blur(18px) saturate(160%);
  backdrop-filter:blur(18px) saturate(160%);
  border-bottom:1px solid rgba(255,255,255,.06);
  transition:height .3s var(--ease),background .3s;
}
.nav.scrolled{height:var(--nav-h-scrolled);background:rgba(7,11,17,.82)}
.nav-inner{display:flex;align-items:center;justify-content:space-between;width:100%}
.nav-logo{display:flex;align-items:center;gap:11px}
.nav-logo img{width:34px;height:34px}
.nav-logo .t{font-size:1.02rem;font-weight:700;letter-spacing:.01em}
.nav-logo .t small{display:block;font-size:.62rem;font-weight:500;letter-spacing:.24em;color:var(--muted);text-transform:uppercase}
.nav-links{display:flex;align-items:center;gap:6px}
.nav-links a{
  padding:8px 14px;font-size:.8rem;font-weight:550;
  letter-spacing:.1em;text-transform:uppercase;color:var(--text-2);
  border-radius:4px;transition:color .2s,background .2s;
}
.nav-links a:hover{color:var(--text);background:rgba(255,255,255,.05)}
.nav-links a.active{color:var(--text)}
.nav-right{display:flex;align-items:center;gap:10px}
.lang-btn{
  padding:7px 13px;font-size:.74rem;font-weight:650;letter-spacing:.12em;
  border:1px solid var(--line-strong);border-radius:4px;color:var(--text-2);
  transition:border-color .2s,color .2s;
}
.lang-btn:hover{border-color:var(--accent);color:var(--accent)}
.nav-toggle{display:none;flex-direction:column;gap:5px;padding:8px}
.nav-toggle span{width:22px;height:2px;background:var(--text);transition:transform .25s var(--ease),opacity .25s}
.nav-toggle.open span:nth-child(1){transform:translateY(7px) rotate(45deg)}
.nav-toggle.open span:nth-child(2){opacity:0}
.nav-toggle.open span:nth-child(3){transform:translateY(-7px) rotate(-45deg)}

/* ---------- hero ---------- */
.hero{
  position:relative;min-height:100svh;
  display:flex;align-items:center;
  padding:calc(var(--nav-h) + 40px) 0 70px;
  overflow:hidden;
  background:
    radial-gradient(900px 560px at 78% 18%,rgba(62,197,255,.10),transparent 62%),
    radial-gradient(700px 500px at 8% 82%,rgba(103,232,249,.05),transparent 60%),
    var(--bg);
}
.hero::after{ /* fine grid */
  content:"";position:absolute;inset:0;pointer-events:none;
  background-image:linear-gradient(rgba(255,255,255,.025) 1px,transparent 1px),
                   linear-gradient(90deg,rgba(255,255,255,.025) 1px,transparent 1px);
  background-size:56px 56px;
  -webkit-mask-image:radial-gradient(900px 600px at 70% 30%,#000 30%,transparent 75%);
  mask-image:radial-gradient(900px 600px at 70% 30%,#000 30%,transparent 75%);
}
.hero-grid{display:grid;grid-template-columns:1.05fr .95fr;gap:48px;align-items:center;position:relative;z-index:2}
.hero-kicker{
  font-size:.74rem;font-weight:650;letter-spacing:.34em;color:var(--accent);text-transform:uppercase;
  display:flex;align-items:center;gap:12px;margin-bottom:22px;
}
.hero-kicker::before{content:"";width:34px;height:1px;background:var(--accent);opacity:.8}
.hero h1{font-size:clamp(2.5rem,5.8vw,4.5rem);font-weight:750;line-height:1.04;letter-spacing:-.035em}
.hero h1 .grad{
  background:linear-gradient(96deg,var(--text) 20%,var(--accent) 88%);
  -webkit-background-clip:text;background-clip:text;color:transparent;
}
.hero-sub{color:var(--text-2);font-size:clamp(1rem,1.5vw,1.18rem);max-width:520px;margin:24px 0 34px}
.hero-actions{display:flex;gap:14px;flex-wrap:wrap}
.hero-meta{
  margin-top:44px;display:grid;grid-template-columns:repeat(3,auto);
  gap:clamp(18px,3vw,42px);padding-top:28px;border-top:1px solid var(--line);
}
.hero-meta b{display:block;font-size:clamp(1.35rem,2.4vw,1.8rem);font-weight:700;letter-spacing:-.02em}
.hero-meta b em{font-style:normal;color:var(--accent);font-size:.55em;letter-spacing:.05em;margin-left:2px}
.hero-meta span{font-size:.72rem;letter-spacing:.16em;text-transform:uppercase;color:var(--muted)}

/* hero product visual */
.hero-visual{position:relative;perspective:1200px}
.hero-stage{
  position:relative;display:flex;align-items:center;justify-content:center;
  min-height:520px;
}
.hero-product{
  position:relative;width:min(390px,72vw);
  filter:drop-shadow(0 40px 80px rgba(0,0,0,.55));
  will-change:transform;
}
.hero-product img{width:100%}
.hero-glow{
  position:absolute;inset:-8% -14%;pointer-events:none;z-index:-1;
  background:radial-gradient(52% 52% at 50% 50%,rgba(62,197,255,.20),rgba(62,197,255,.05) 55%,transparent 72%);
  filter:blur(6px);
}
.hero-floor{
  position:absolute;left:50%;bottom:2%;transform:translateX(-50%);
  width:78%;height:1px;
  background:linear-gradient(90deg,transparent,rgba(62,197,255,.55),transparent);
  box-shadow:0 0 22px rgba(62,197,255,.5),0 0 60px rgba(62,197,255,.22);
}
.hero-floor::after{
  content:"";position:absolute;left:50%;bottom:-38px;transform:translateX(-50%);
  width:120%;height:80px;pointer-events:none;
  background:radial-gradient(50% 60% at 50% 0%,rgba(62,197,255,.10),transparent 70%);
}
.hero-tag{
  position:absolute;display:flex;gap:10px;align-items:flex-start;
  background:rgba(10,16,24,.72);border:1px solid var(--line-strong);
  border-radius:var(--radius);padding:12px 16px;max-width:200px;
  -webkit-backdrop-filter:blur(10px);backdrop-filter:blur(10px);
  animation:floaty 7s ease-in-out infinite;
}
.hero-tag b{display:block;font-size:.86rem;font-weight:650}
.hero-tag span{font-size:.7rem;color:var(--muted);letter-spacing:.04em}
.hero-tag .dot-g{width:8px;height:8px;border-radius:50%;background:var(--ok);box-shadow:0 0 10px var(--ok);margin-top:4px;flex:none}
.hero-tag.t1{top:12%;left:-6%}
.hero-tag.t2{bottom:20%;right:-4%;animation-delay:1.4s}
.hero-tag.t3{bottom:-4%;left:6%;animation-delay:2.6s}
@keyframes floaty{0%,100%{transform:translateY(0)}50%{transform:translateY(-9px)}}
.hero-scroll{
  position:absolute;left:50%;bottom:26px;transform:translateX(-50%);
  display:flex;flex-direction:column;align-items:center;gap:8px;
  color:var(--muted);font-size:.64rem;letter-spacing:.3em;text-transform:uppercase;
}
.hero-scroll .ln{width:1px;height:44px;background:linear-gradient(var(--accent),transparent);position:relative;overflow:hidden}
.hero-scroll .ln::after{content:"";position:absolute;top:-40%;left:0;width:100%;height:40%;background:var(--accent);animation:scrollln 2.2s var(--ease) infinite}
@keyframes scrollln{to{top:110%}}

/* ---------- section reveal ---------- */
.reveal{opacity:0;transform:translateY(26px);transition:opacity .8s var(--ease),transform .8s var(--ease)}
.reveal.in{opacity:1;transform:none}
.reveal[data-delay="1"]{transition-delay:.1s}
.reveal[data-delay="2"]{transition-delay:.2s}
.reveal[data-delay="3"]{transition-delay:.3s}

/* ---------- footer ---------- */
.footer{border-top:1px solid var(--line);background:var(--bg-2);padding:64px 0 36px}
.footer-grid{display:grid;grid-template-columns:1.4fr 1fr 1fr 1fr;gap:44px}
.footer h4{font-size:.78rem;letter-spacing:.18em;text-transform:uppercase;color:var(--text);margin-bottom:18px;font-weight:650}
.footer a{display:block;color:var(--muted);font-size:.9rem;padding:5px 0;transition:color .2s}
.footer a:hover{color:var(--accent)}
.footer .brand p{color:var(--muted);font-size:.9rem;max-width:300px;margin-top:14px}
.footer .bottom{
  margin-top:48px;padding-top:24px;border-top:1px solid var(--line);
  display:flex;justify-content:space-between;gap:12px;flex-wrap:wrap;
  color:var(--muted);font-size:.78rem;
}

/* ---------- misc ---------- */
.divider{height:1px;background:linear-gradient(90deg,transparent,var(--line-strong),transparent);border:0}
[hidden]{display:none!important}
@media (prefers-reduced-motion:reduce){
  *,*::before,*::after{animation-duration:.01ms!important;transition-duration:.01ms!important;scroll-behavior:auto!important}
}