:root{
  --bg:#0a0e0a;
  --panel:#141a14;
  --panel2:#0f130f;
  --green:#33ff66;
  --green-dim:#1a8a37;
  --amber:#ffb000;
  --red:#ff3b3b;
  --blue:#4db8ff;
  --line:#26331f;
}
*{box-sizing:border-box;}
html,body{margin:0;padding:0;}
body{
  background:
    radial-gradient(circle at 20% 0%, #16220f 0%, transparent 55%),
    radial-gradient(circle at 90% 100%, #101a20 0%, transparent 50%),
    var(--bg);
  color:var(--green);
  font-family:'Share Tech Mono', monospace;
  min-height:100vh;
}
.crt-overlay{
  position:fixed;inset:0;pointer-events:none;z-index:999;
  background:repeating-linear-gradient(to bottom, rgba(0,0,0,0.12) 0 1px, transparent 1px 3px);
  mix-blend-mode:multiply;
  animation:flicker 4s infinite;
}
@keyframes flicker{0%,100%{opacity:.55}48%{opacity:.6}50%{opacity:.45}}

#app{max-width:900px;margin:0 auto;padding:16px 14px 40px;}

header{text-align:center;border-bottom:1px solid var(--line);padding-bottom:12px;margin-bottom:14px;}
h1{
  font-family:'VT323', monospace;
  font-size:clamp(28px,7vw,52px);
  margin:0;
  color:var(--green);
  text-shadow:0 0 8px rgba(51,255,102,.6),0 0 20px rgba(51,255,102,.25);
  letter-spacing:1px;
}
.subtitle{color:var(--green-dim);margin:2px 0 10px;font-size:13px;letter-spacing:2px;}
.leds{display:flex;gap:14px;justify-content:center;align-items:center;flex-wrap:wrap;font-size:11px;color:#7fae7f;}
.led-item{display:flex;align-items:center;gap:5px;}
.led{width:11px;height:11px;border-radius:50%;background:#222;border:1px solid #000;box-shadow:inset 0 0 3px #000;}
.led.on.led-green{background:var(--green);box-shadow:0 0 8px var(--green);}
.led.on.led-red{background:var(--red);box-shadow:0 0 8px var(--red);animation:blink .6s infinite;}
.led.on.led-amber{background:var(--amber);box-shadow:0 0 8px var(--amber);animation:blink .8s infinite;}
.led.on.led-blue{background:var(--blue);box-shadow:0 0 8px var(--blue);}
@keyframes blink{50%{opacity:.35}}
#help-btn{
  background:var(--panel);color:var(--amber);border:1px solid var(--amber);
  border-radius:50%;width:22px;height:22px;cursor:pointer;font-weight:bold;line-height:1;
}

.tabs{display:flex;gap:8px;margin-bottom:14px;}
.tab{
  flex:1;padding:12px 8px;background:var(--panel2);color:var(--green-dim);
  border:1px solid var(--line);cursor:pointer;font-family:'Share Tech Mono',monospace;
  font-size:14px;letter-spacing:1px;transition:.15s;
}
.tab:hover{color:var(--green);}
.tab.active{
  background:var(--panel);color:var(--green);border-color:var(--green-dim);
  box-shadow:inset 0 0 14px rgba(51,255,102,.15),0 0 10px rgba(51,255,102,.2);
}

.panel{background:var(--panel);border:1px solid var(--line);border-radius:6px;padding:16px;box-shadow:0 8px 24px rgba(0,0,0,.5);}
.panel.hidden{display:none;}

.row{display:flex;gap:16px;flex-wrap:wrap;}
.col{flex:1;min-width:260px;display:flex;flex-direction:column;gap:12px;}

.dropzone{
  border:2px dashed var(--green-dim);border-radius:6px;background:var(--panel2);
  padding:22px 14px;text-align:center;cursor:pointer;transition:.15s;
}
.dropzone:hover,.dropzone.drag-over{border-color:var(--green);background:#101710;box-shadow:inset 0 0 20px rgba(51,255,102,.1);}
.dropzone.has-image{border-style:solid;border-color:var(--green-dim);}
.dz-inner{display:flex;flex-direction:column;gap:6px;align-items:center;color:#8bc38b;}
.dz-icon{font-size:30px;}
.dz-sub{font-size:11px;color:var(--green-dim);}

.opt-row{font-size:12px;color:#8bc38b;}
.opt-row input{accent-color:var(--green);}

.btn-row{display:flex;gap:8px;flex-wrap:wrap;}
.btn{
  flex:1;min-width:120px;padding:11px 10px;cursor:pointer;
  background:linear-gradient(#1c281c,#121a12);
  color:var(--green);border:1px solid var(--green-dim);border-radius:4px;
  font-family:'Share Tech Mono',monospace;font-size:13px;letter-spacing:.5px;
  box-shadow:0 2px 0 #000, inset 0 1px 0 rgba(255,255,255,.06);
  transition:.12s;
}
.btn:hover:not(:disabled){color:#fff;box-shadow:0 0 12px rgba(51,255,102,.4),0 2px 0 #000;}
.btn:active:not(:disabled){transform:translateY(2px);box-shadow:0 0 8px rgba(51,255,102,.3);}
.btn:disabled{opacity:.35;cursor:not-allowed;}

.freq-readout{
  font-family:'VT323',monospace;font-size:22px;text-align:center;
  color:var(--amber);text-shadow:0 0 8px rgba(255,176,0,.5);
  background:#0a0d08;border:1px solid var(--line);border-radius:4px;padding:6px;
}

.timeline{position:relative;height:22px;background:#0a0d08;border:1px solid var(--line);border-radius:4px;overflow:hidden;}
.playhead{position:absolute;top:0;left:0;width:2px;height:100%;background:var(--amber);box-shadow:0 0 8px var(--amber);transition:left .1s linear;}
.tl-label{position:absolute;right:8px;top:2px;font-size:12px;color:#8bc38b;}

.canvas-wrap{background:#000;border:1px solid var(--line);border-radius:4px;padding:8px;}
.canvas-title{font-size:11px;color:var(--green-dim);letter-spacing:2px;margin-bottom:6px;}
#src-canvas,#dst-canvas{
  width:100%;height:auto;display:block;image-rendering:pixelated;
  border:1px solid #000;background:#000;
}

.waterfall-wrap{margin-top:14px;background:#000;border:1px solid var(--line);border-radius:4px;padding:8px;}
.waterfall{width:100%;height:auto;display:block;image-rendering:pixelated;background:#020402;}

.status{
  margin-top:12px;padding:9px 12px;background:#0a0d08;border-left:3px solid var(--green-dim);
  border-radius:2px;font-size:13px;color:#a7d6a7;min-height:20px;
}

footer{
  margin-top:24px;text-align:center;font-size:11px;color:var(--green-dim);
  border-top:1px solid var(--line);padding-top:14px;
  display:flex;justify-content:space-between;flex-wrap:wrap;gap:8px;
}
footer a{color:var(--amber);text-decoration:none;border-bottom:1px dotted var(--amber);}
footer a:hover{color:#fff;}

.modal{position:fixed;inset:0;background:rgba(0,0,0,.8);display:flex;align-items:center;justify-content:center;z-index:1000;padding:16px;}
.modal.hidden{display:none;}
.modal-box{background:var(--panel);border:1px solid var(--green-dim);border-radius:8px;max-width:460px;padding:22px;box-shadow:0 0 40px rgba(51,255,102,.2);}
.modal-box h2{margin-top:0;color:var(--green);font-family:'VT323',monospace;font-size:28px;}
.modal-box p{color:#a7d6a7;font-size:13px;line-height:1.5;}
.spec-table{width:100%;border-collapse:collapse;margin:12px 0;font-size:12px;}
.spec-table th,.spec-table td{border:1px solid var(--line);padding:5px 8px;text-align:left;color:#a7d6a7;}
.spec-table th{color:var(--amber);background:#0a0d08;}

@media(max-width:560px){
  .col{min-width:100%;}
  footer{flex-direction:column;}
}