:root {
  --bg: #05060a;
  --fg: #e8ecf4;
  --muted: #7b8496;
  --accent: #7aa2ff;
  --glass: rgba(255, 255, 255, 0.04);
  --border: rgba(255, 255, 255, 0.12);
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  height: 100%;
  background: var(--bg);
  color: var(--fg);
  font-family: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  overflow: hidden;
  -webkit-tap-highlight-color: transparent;
}

#stage {
  position: fixed;
  inset: 0;
  width: 100vw;
  height: 100vh;
  display: block;
  cursor: crosshair;
}

/* ---- Overlay card ---- */
#overlay {
  position: fixed;
  inset: 0;
  display: grid;
  place-items: center;
  background: radial-gradient(120% 120% at 50% 0%, rgba(20,30,60,0.35), transparent 60%), var(--bg);
  transition: opacity 0.6s ease, visibility 0.6s;
  z-index: 10;
}
#overlay.hidden { opacity: 0; visibility: hidden; pointer-events: none; }

.card {
  width: min(92vw, 420px);
  padding: 28px 26px;
  border: 1px solid var(--border);
  border-radius: 18px;
  background: var(--glass);
  backdrop-filter: blur(10px);
  text-align: left;
}
.brand {
  font-size: 34px;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 6px;
}
.tagline { color: var(--muted); margin: 0 0 22px; font-size: 14px; line-height: 1.5; }

.controls { display: flex; flex-direction: column; gap: 16px; }

button.primary {
  width: 100%;
  padding: 14px;
  border: none;
  border-radius: 12px;
  background: var(--accent);
  color: #0a1020;
  font-size: 16px;
  font-weight: 600;
  cursor: pointer;
  transition: transform 0.08s ease, filter 0.2s;
}
button.primary:hover { filter: brightness(1.08); }
button.primary:active { transform: scale(0.98); }

.row { display: flex; align-items: center; gap: 12px; font-size: 13px; color: var(--muted); }
.row label { width: 92px; flex-shrink: 0; }

select, input[type="range"] {
  flex: 1;
  background: rgba(0,0,0,0.3);
  border: 1px solid var(--border);
  color: var(--fg);
  border-radius: 8px;
  padding: 8px 10px;
  font-size: 14px;
}
input[type="range"] { padding: 0; accent-color: var(--accent); }

.status { margin-top: 18px; font-size: 12px; color: var(--muted); text-align: center; }
.status.err { color: #ff7a7a; }

/* ---- Floating stop/start button ---- */
.fab {
  position: fixed;
  right: 20px;
  bottom: 24px;
  z-index: 9;
  border: 1px solid var(--border);
  background: rgba(10,12,20,0.7);
  backdrop-filter: blur(8px);
  color: var(--fg);
  border-radius: 999px;
  padding: 10px 16px;
  font-size: 13px;
  cursor: pointer;
}
.fab:hover { background: rgba(20,24,36,0.9); }