:root{
    --panel:#131313; --bg:#0e0e10; --fg:#e7e7ea; --bd:#23232a;
  }
  *{box-sizing:border-box;font-family:system-ui,Segoe UI,Roboto,Arial}
  html,body{height:100%}
  body{margin:0;background:var(--bg);color:var(--fg);display:grid;grid-template-rows:auto 1fr;gap:clamp(8px,1.8vw,14px);padding:clamp(8px,1.8vw,14px)}
  header{display:flex;align-items:center;justify-content:space-between;gap:10px;flex-wrap:wrap}
  header h1{font-size:clamp(14px,2.2vw,18px);margin:0;font-weight:600;opacity:.92}
  .main{display:grid;gap:clamp(8px,1.8vw,12px);grid-template-columns:minmax(0,1fr) minmax(300px,460px)}
  @media (max-width:1000px){.main{grid-template-columns:1fr}}
  .sign-wrap{display:grid;place-items:center;height:100%;min-height:240px;padding:clamp(6px,1.5vw,12px)}
  .sign{position:relative;background:linear-gradient(#0b0b0b,#222);border:clamp(6px,1.2vw,10px) solid #0a0a0a;border-radius:10px;box-shadow: inset 0 0 0 1px #000, 0 12px 18px rgba(0,0,0,.55), 0 2px 0 0 #000 inset; padding:clamp(10px,1.8vw,14px) clamp(10px,1.8vw,14px) clamp(12px,2vw,18px); transform-origin:top left;max-width:100%}
  .panel{position:relative;background:linear-gradient(var(--panel),#0f0f0f);border-radius:6px;box-shadow:inset 0 -1px 0 #000,inset 0 1px 0 #2a2a2a80}
  canvas{display:block;max-width:100%;height:auto}
  .ctrls{height:100%;overflow:auto;padding:clamp(8px,1.6vw,12px);background:#101014;border:1px solid var(--bd);border-radius:12px;display:grid;gap:12px}
  .group{display:grid;gap:8px}
  .row{display:flex;gap:8px;align-items:center;flex-wrap:wrap}
  .pill{background:#181820;border:1px solid #2b2b34;padding:8px 12px;border-radius:999px;font-size:clamp(12px,1.8vw,13px)}
  input[type="text"],input[type="number"],input[type="color"],select,button{width:100%;padding:10px 12px;background:#0f0f13;color:#f3f3f6;border:1px solid #2b2b34;border-radius:10px;font-size:clamp(13px,2vw,14px)}
  .tight{width:auto;padding:8px 10px}
  button.btn{cursor:pointer}
  button.btn:active{transform:translateY(1px)}
  .mono{font-family: ui-monospace, Menlo, Consolas, monospace;}
  .tiny{font-size:clamp(11px,1.8vw,12px);opacity:.75}
/* --- Toast notifications --- */
#toasts{position:fixed;z-index:9999;inset:auto clamp(8px,2vw,16px) clamp(8px,2vw,16px) auto;display:grid;gap:8px;pointer-events:none}
.toast{min-width:200px;max-width:min(92vw,420px);background:#12121a;border:1px solid #2b2b34;border-left:6px solid #4a83ff;
  color:#f2f2f7;padding:12px 14px;border-radius:12px;box-shadow:0 8px 18px rgba(0,0,0,.45);opacity:0;transform:translateY(8px);transition:opacity .18s ease, transform .18s ease}
.toast.show{opacity:1;transform:translateY(0)}
.toast.success{border-left-color:#2ecc71}
.toast.error{border-left-color:#e74c3c}

/* --- Responsive refinements --- */
@media (max-width: 720px){
  .main{grid-template-columns:1fr}
  .ctrls{gap:10px;padding:12px}
  .row{gap:6px}
  .pill, input[type="text"], input[type="number"], input[type="color"], select, button{width:100%}
  .tight{width:auto}
  header{position:sticky;top:0;z-index:10;background:linear-gradient(var(--bg), color-mix(in srgb, var(--bg), transparent 60%));padding-bottom:8px}
  .sign-wrap{min-height:200px}
}

/* Improve touch targets */
button.btn, .pill input[type="checkbox"] + label, .pill label{min-height:40px}