:root{
  --bg:#0b0c10; --text:#eef0f6; --muted:#9aa0ad; --line:#2a2e3a;
  --accent:#6ea8fe; --accent-2:#b692ff; --red:#ff6b6b;
}
*{box-sizing:border-box;}
html,body{margin:0;height:100%;}
body{
  color:var(--text); overflow:hidden;
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Inter,Roboto,sans-serif;
  /* deep base with a faint blue/violet glow for depth behind the network */
  background:
    radial-gradient(60vw 60vw at 18% 12%, rgba(110,168,254,.10), transparent 60%),
    radial-gradient(55vw 55vw at 85% 88%, rgba(182,146,255,.10), transparent 60%),
    var(--bg);
}

/* connecting-points network */
.net{position:fixed;inset:0;z-index:0;display:block;}

.stage{position:relative;z-index:1;height:100%;display:flex;align-items:center;justify-content:center;padding:24px;}
.card{
  width:100%;max-width:420px;text-align:center;
  background:rgba(18,20,28,.5);border:1px solid var(--line);
  border-radius:22px;padding:40px 34px;backdrop-filter:blur(18px);
  box-shadow:0 30px 80px -20px rgba(0,0,0,.8);
  animation:rise .7s cubic-bezier(.2,.8,.2,1) both;
}
@keyframes rise{from{opacity:0;transform:translateY(18px);}to{opacity:1;transform:none;}}

.logo{
  font-size:58px;font-weight:800;letter-spacing:-1px;line-height:1;
  background:linear-gradient(100deg,var(--accent),var(--accent-2));
  -webkit-background-clip:text;background-clip:text;color:transparent;
}
.tag{margin:6px 0 30px;color:var(--muted);letter-spacing:6px;text-transform:uppercase;font-size:13px;}

.lab{display:block;color:var(--muted);font-size:13px;margin-bottom:12px;}
.inwrap{display:flex;gap:10px;align-items:center;}
.code{
  flex:1;min-width:0;background:rgba(0,0,0,.35);border:1px solid var(--line);color:var(--text);
  font-size:22px;letter-spacing:6px;text-align:center;text-transform:uppercase;
  padding:14px 16px;border-radius:14px;outline:none;transition:.15s;font-weight:700;
}
.code:focus{border-color:var(--accent);box-shadow:0 0 0 4px rgba(110,168,254,.18);}
.code::placeholder{letter-spacing:8px;color:#3a3f4c;}
.go{
  width:54px;height:54px;flex:0 0 54px;border:none;border-radius:14px;cursor:pointer;
  font-size:22px;color:#0b1020;font-weight:800;
  background:linear-gradient(100deg,var(--accent),var(--accent-2));transition:.15s;
}
.go:hover{filter:brightness(1.08);transform:translateX(2px);}
.go:disabled{opacity:.5;cursor:default;transform:none;}

.err{min-height:18px;margin:14px 0 0;color:var(--red);font-size:13px;}
.foot{margin:28px 0 4px;color:#aeb4c2;font-size:20px;font-weight:600;letter-spacing:.3px;}

.shake{animation:shake .4s;}
@keyframes shake{10%,90%{transform:translateX(-2px);}30%,70%{transform:translateX(5px);}50%{transform:translateX(-7px);}}

/* phones */
@media (max-width:520px){
  .stage{padding:18px;}
  .card{max-width:none;padding:30px 22px;border-radius:18px;}
  .logo{font-size:46px;}
  .tag{letter-spacing:4px;font-size:11px;margin-bottom:22px;}
  .lab{font-size:12px;}
  .inwrap{gap:8px;}
  .code{font-size:18px;letter-spacing:4px;padding:13px 10px;}
  .go{width:48px;height:48px;flex:0 0 48px;font-size:20px;border-radius:12px;}
  .foot{font-size:17px;margin-top:22px;}
}