:root {
  --bg: #050a07;
  --panel: #0a140e;
  --green: #00ff9c;
  --amber: #ffb000;
  --red: #ff3b6b;
  --dim: #3a5f4c;
  --border: #123c2a;
}
* { box-sizing: border-box; }
html, body {
  margin: 0; padding: 0;
  background:
    radial-gradient(circle at 50% -10%, #0d2418 0%, var(--bg) 60%),
    var(--bg);
  color: var(--green);
  font-family: 'Share Tech Mono', monospace;
  min-height: 100vh;
}
/* CRT scanline overlay */
.scanlines {
  pointer-events: none;
  position: fixed; inset: 0; z-index: 999;
  background: repeating-linear-gradient(
    to bottom, rgba(0,0,0,0) 0px, rgba(0,0,0,0) 2px,
    rgba(0,0,0,0.18) 3px, rgba(0,0,0,0.18) 4px);
  mix-blend-mode: multiply;
}

header {
  text-align: center;
  padding: 24px 12px 8px;
}
h1 {
  font-family: 'VT323', monospace;
  font-size: clamp(2.4rem, 8vw, 4.5rem);
  font-weight: 400;
  margin: 0;
  color: var(--green);
  text-shadow: 0 0 12px rgba(0,255,156,0.7), 0 0 32px rgba(0,255,156,0.3);
  letter-spacing: 2px;
}
.subtitle {
  color: var(--dim);
  font-size: 0.85rem;
  margin: 4px 0 0;
}

main {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  max-width: 1100px;
  margin: 12px auto;
  padding: 0 14px;
}
@media (max-width: 760px) {
  main { grid-template-columns: 1fr; }
}

.panel {
  background: var(--panel);
  border: 2px solid var(--border);
  border-radius: 6px;
  padding: 14px;
  box-shadow: inset 0 0 30px rgba(0,255,156,0.05), 0 0 20px rgba(0,0,0,0.6);
}
.panel h2 {
  font-family: 'VT323', monospace;
  font-size: 1.6rem;
  margin: 0 0 12px;
  color: var(--green);
  text-shadow: 0 0 8px rgba(0,255,156,0.5);
  display: flex; align-items: center; gap: 10px;
}
.rec-dot {
  font-size: 0.7rem; color: var(--red); opacity: 0.2;
  margin-left: auto; letter-spacing: 1px;
}
.rec-dot.on { opacity: 1; animation: blink 1s steps(2) infinite; text-shadow: 0 0 8px var(--red); }
@keyframes blink { 50% { opacity: 0.25; } }

/* CRT display for video/canvas */
.crt {
  position: relative;
  background: #020604;
  border-radius: 14px;
  padding: 10px;
  border: 2px solid #0f2c1e;
  box-shadow: inset 0 0 40px rgba(0,0,0,0.9), 0 0 15px rgba(0,255,156,0.1);
  aspect-ratio: 4/3;
  overflow: hidden;
  display: flex; align-items: center; justify-content: center;
}
.crt::after {
  content: ''; position: absolute; inset: 0; border-radius: 14px;
  background: radial-gradient(ellipse at center, transparent 55%, rgba(0,0,0,0.55) 100%);
  pointer-events: none;
}
#cam { display: none; }
#tx-mini, #rx-mon {
  width: 100%; height: 100%;
  image-rendering: pixelated;
  object-fit: contain;
  filter: saturate(1.1) contrast(1.05);
}

.btn-row {
  display: flex; flex-wrap: wrap; gap: 8px;
  margin: 12px 0;
}
button {
  font-family: 'Share Tech Mono', monospace;
  font-size: 0.85rem;
  background: #08251a;
  color: var(--green);
  border: 2px solid var(--green);
  padding: 9px 14px;
  cursor: pointer;
  border-radius: 3px;
  box-shadow: 0 3px 0 #003a26, 0 0 8px rgba(0,255,156,0.15);
  transition: transform 0.05s, box-shadow 0.05s, background 0.15s;
  letter-spacing: 1px;
}
button:hover:not(:disabled) { background: #0d3a29; }
button:active:not(:disabled) { transform: translateY(3px); box-shadow: 0 0 0 #003a26; }
button:disabled { opacity: 0.35; cursor: not-allowed; }
button.active {
  background: var(--red); color: #fff; border-color: var(--red);
  box-shadow: 0 3px 0 #7a1030, 0 0 14px rgba(255,59,107,0.5);
}

.osc-wrap { position: relative; margin-top: 6px; }
.osc-label {
  position: absolute; top: 4px; left: 8px; z-index: 2;
  font-size: 0.6rem; color: var(--dim); letter-spacing: 2px;
}
#tx-osc, #rx-spec {
  width: 100%; height: 90px; display: block;
  border: 1px solid var(--border); border-radius: 4px;
  background: #04140c;
}

.readout {
  margin-top: 10px;
  font-size: 0.8rem;
  color: var(--green);
  display: flex; align-items: center; gap: 10px; flex-wrap: wrap;
}
.sync {
  font-family: 'VT323', monospace; font-size: 1.1rem;
  padding: 2px 8px; border-radius: 3px;
}
.sync.searching { color: var(--amber); text-shadow: 0 0 6px var(--amber); animation: pulse 1.2s infinite; }
.sync.locked { color: var(--green); text-shadow: 0 0 8px var(--green); background: rgba(0,255,156,0.1); }
@keyframes pulse { 50% { opacity: 0.4; } }
.vu-wrap {
  flex: 1; min-width: 60px; height: 8px;
  background: #041a10; border: 1px solid var(--border); border-radius: 4px;
  overflow: hidden;
}
.vu-bar {
  height: 100%; width: 0%;
  background: linear-gradient(90deg, var(--green), var(--amber), var(--red));
  transition: width 0.08s;
}

/* Control bar */
.controls {
  max-width: 1100px; margin: 10px auto; padding: 12px 16px;
  display: flex; flex-wrap: wrap; gap: 14px; align-items: flex-end;
  background: var(--panel);
  border: 2px solid var(--border); border-radius: 6px;
}
.ctrl { display: flex; flex-direction: column; gap: 3px; }
.ctrl label { font-size: 0.62rem; color: var(--dim); letter-spacing: 1px; text-transform: uppercase; }
.ctrl input, .ctrl select {
  background: #04140c; color: var(--green);
  border: 1px solid var(--green); border-radius: 3px;
  font-family: 'Share Tech Mono', monospace; font-size: 0.8rem;
  padding: 5px 6px; width: 90px;
}
.ctrl input[type=range] { width: 110px; padding: 0; }
.fps-est span {
  font-family: 'VT323', monospace; font-size: 1.4rem;
  color: var(--amber); text-shadow: 0 0 6px var(--amber);
}

/* How it works */
.howto {
  max-width: 1100px; margin: 10px auto; padding: 0 16px;
}
.howto summary {
  cursor: pointer; color: var(--amber); font-size: 0.9rem;
  padding: 8px 0; list-style: none; letter-spacing: 1px;
}
.howto summary::-webkit-details-marker { display: none; }
.howto[open] summary { color: var(--green); }
.howto-body {
  background: var(--panel); border: 2px solid var(--border);
  border-radius: 6px; padding: 14px 18px; font-size: 0.85rem;
  color: #b8e6d4; line-height: 1.5;
}
.howto-body b { color: var(--green); }
.diagram {
  background: #04140c; border: 1px solid var(--border);
  padding: 10px; color: var(--green); font-size: 0.75rem;
  overflow-x: auto; border-radius: 4px;
}
.howto-body .warn { color: var(--amber); }
.howto-body ul { margin: 8px 0; }

footer {
  max-width: 1100px; margin: 24px auto 40px; padding: 14px 16px;
  display: flex; justify-content: space-between; flex-wrap: wrap; gap: 8px;
  font-size: 0.75rem; color: var(--dim);
  border-top: 1px solid var(--border);
}
footer a { color: var(--green); text-decoration: none; border-bottom: 1px dotted var(--green); }
footer a:hover { text-shadow: 0 0 6px var(--green); }
</parameter>