:root{
  --bg: #0b0b0b;
  --panel: #0b0b0b;
  --ui-bg: #111;
  --accent: #29a;
}
*{box-sizing:border-box}
html,body{height:100%;margin:0;font-family:Segoe UI,Roboto,Arial,Helvetica,sans-serif;background:linear-gradient(180deg,#050505,#0a0a0a);color:#ddd}
main{max-width:1100px;margin:18px auto;padding:18px}
h1{margin:0 0 12px 0}
.controls{display:flex;flex-wrap:wrap;gap:12px;align-items:center;background:rgba(255,255,255,0.03);padding:12px;border-radius:8px}
.controls label{display:flex;flex-direction:column;font-size:13px;min-width:160px}
.controls input[type=file]{margin-top:6px}
.controls input[type=range]{width:220px}
.buttons{display:flex;gap:8px;margin-top:6px}
button{background:var(--accent);color:white;border:none;padding:8px 12px;border-radius:6px;cursor:pointer}
button:active{transform:translateY(1px)}
.preview{margin-top:16px;background:#000;padding:16px;border-radius:8px;display:flex;justify-content:center;align-items:center}
#ledCanvas{background:#000;border-radius:6px;display:block;max-width:100%;height:auto}
.help{margin-top:12px;color:#aaa;font-size:13px}

@media (max-width:640px){
  .controls{gap:8px}
  .controls input[type=range]{width:150px}
}