/* =========================================================================
 * Theremin / XY pad. One big rectangular surface, scale-line grid in the
 * background, fingers leave glowing crosshair touch markers. The first
 * finger drives pitch (X) + volume (Y); a second finger overlays vibrato
 * (X = rate, Y = depth).
 * ========================================================================= */

.theremin-stage {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 8px 16px 24px;
  width: 100%;
}

.theremin-pad {
  position: relative;
  width: min(100%, 1080px);
  height: clamp(320px, 60vh, 580px);
  border-radius: 18px;
  background:
    radial-gradient(
      120% 80% at 50% 100%,
      rgba(244, 114, 182, 0.18),
      transparent 60%
    ),
    radial-gradient(
      120% 80% at 50% 0%,
      rgba(129, 140, 248, 0.18),
      transparent 60%
    ),
    linear-gradient(180deg, #1e293b, #0b1224);
  border: 1px solid var(--border);
  box-shadow:
    0 24px 40px -20px rgba(0, 0, 0, 0.6),
    inset 0 1px 0 rgba(255, 255, 255, 0.04),
    inset 0 0 0 1px rgba(129, 140, 248, 0.08);
  overflow: hidden;
  user-select: none;
  -webkit-user-select: none;
  touch-action: none;
  cursor: crosshair;
}

/* SVG-style grid drawn in CSS: vertical lines = pitch divisions, horizontal
 * lines = volume contours. The vertical lines are positioned by JS via CSS
 * variables for the active scale; horizontal lines are fixed thirds. */
.theremin-grid {
  position: absolute;
  inset: 0;
  pointer-events: none;
}

.theremin-grid-line {
  position: absolute;
  background: rgba(148, 163, 184, 0.08);
  pointer-events: none;
}

.theremin-grid-line.vertical {
  top: 0;
  bottom: 0;
  width: 1px;
}

.theremin-grid-line.vertical.is-c {
  background: rgba(129, 140, 248, 0.32);
  width: 1.5px;
}

.theremin-grid-line.vertical.is-root {
  background: rgba(244, 114, 182, 0.4);
  width: 1.5px;
}

.theremin-grid-line.horizontal {
  left: 0;
  right: 0;
  height: 1px;
}

/* Note labels along the bottom edge for each octave's C (or root). */
.theremin-grid-label {
  position: absolute;
  bottom: 6px;
  transform: translateX(-50%);
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: rgba(226, 232, 240, 0.45);
  pointer-events: none;
  text-shadow: 0 1px 2px rgba(0, 0, 0, 0.6);
}

.theremin-grid-label.is-root {
  color: rgba(244, 114, 182, 0.85);
}

.theremin-grid-label.is-edge-left {
  transform: translateX(4px);
}

.theremin-grid-label.is-edge-right {
  transform: translateX(-100%) translateX(-4px);
}

/* Volume gradient overlay — subtle vertical fade so it reads "louder up". */
.theremin-pad::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(
    180deg,
    rgba(129, 140, 248, 0.12),
    transparent 50%,
    rgba(0, 0, 0, 0.18)
  );
  pointer-events: none;
}

.theremin-axis-label {
  position: absolute;
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 0.18em;
  color: rgba(148, 163, 184, 0.55);
  pointer-events: none;
  text-transform: uppercase;
}

.theremin-axis-x {
  bottom: 6px;
  right: 12px;
}

.theremin-axis-y {
  top: 12px;
  left: 12px;
  writing-mode: vertical-rl;
  transform: rotate(180deg);
}

.theremin-hint {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  color: rgba(226, 232, 240, 0.35);
  font-size: 14px;
  letter-spacing: 0.04em;
  text-align: center;
  pointer-events: none;
  transition: opacity 240ms ease;
}

.theremin-pad.is-active .theremin-hint {
  opacity: 0;
}

/* Touch markers — one per active pointer. Position is set live via
 * --tx / --ty (in px). Two flavours: primary (pitch+volume) and
 * vibrato (secondary fingers). */
.theremin-touch {
  position: absolute;
  left: var(--tx, 0);
  top: var(--ty, 0);
  width: 96px;
  height: 96px;
  margin-left: -48px;
  margin-top: -48px;
  border-radius: 50%;
  pointer-events: none;
  background: radial-gradient(
    circle at 50% 50%,
    rgba(129, 140, 248, 0.55),
    rgba(129, 140, 248, 0.08) 50%,
    transparent 70%
  );
  filter: blur(0.5px);
  will-change: left, top;
}

.theremin-touch::after {
  /* Inner crisp dot. */
  content: '';
  position: absolute;
  left: 50%;
  top: 50%;
  width: 18px;
  height: 18px;
  margin: -9px 0 0 -9px;
  border-radius: 50%;
  background: rgba(226, 232, 240, 0.95);
  box-shadow:
    0 0 0 3px rgba(129, 140, 248, 0.5),
    0 0 18px rgba(129, 140, 248, 0.6);
}

.theremin-touch.vibrato {
  background: radial-gradient(
    circle at 50% 50%,
    rgba(244, 114, 182, 0.55),
    rgba(244, 114, 182, 0.08) 50%,
    transparent 70%
  );
}

.theremin-touch.vibrato::after {
  background: rgba(252, 211, 230, 0.95);
  box-shadow:
    0 0 0 3px rgba(244, 114, 182, 0.55),
    0 0 18px rgba(244, 114, 182, 0.6);
}

/* Crosshair lines through the primary touch — a long horizontal pitch
 * axis and a long vertical volume axis so the player can read off the
 * note from the labels at the bottom. */
.theremin-crosshair {
  position: absolute;
  inset: 0;
  pointer-events: none;
}

.theremin-crosshair-line {
  position: absolute;
  background: rgba(129, 140, 248, 0.35);
  pointer-events: none;
}

.theremin-crosshair-line.vertical {
  top: 0;
  bottom: 0;
  width: 1.5px;
  left: var(--cx, -10px);
  margin-left: -0.75px;
  box-shadow: 0 0 12px rgba(129, 140, 248, 0.5);
}

.theremin-crosshair-line.horizontal {
  left: 0;
  right: 0;
  height: 1.5px;
  top: var(--cy, -10px);
  margin-top: -0.75px;
  box-shadow: 0 0 12px rgba(129, 140, 248, 0.5);
}

@media (prefers-reduced-motion: reduce) {
  .theremin-touch {
    filter: none;
  }
}

/* ---------- Air mode ---------- *
 * The same pad doubles as a camera-feed display with hand-landmark
 * overlay. Switching modes flips a class on the pad: in touch mode the
 * video and canvas are display:none, in air mode they fill the pad and
 * the touch markers + crosshair are hidden. The grid overlay stays
 * visible in both so the player can read off the note from the labels.
 */

.theremin-video,
.theremin-overlay {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  display: none;
  pointer-events: none;
}

.theremin-video {
  object-fit: cover;
  /* Mirror so left-handed motion in the real world goes left in the
   * frame — the natural "mirror" feel for selfie cameras. */
  transform: scaleX(-1);
  opacity: 0.45;
  background: #000;
}

.theremin-overlay {
  /* The canvas already paints its own background-transparent landmark
   * skeleton; we just need it on top of the video. */
  z-index: 2;
}

.theremin-pad.is-air-mode {
  cursor: default;
}

.theremin-pad.is-air-mode .theremin-video,
.theremin-pad.is-air-mode .theremin-overlay {
  display: block;
}

.theremin-pad.is-air-mode .theremin-touch,
.theremin-pad.is-air-mode .theremin-crosshair {
  display: none;
}

.theremin-pad.is-air-mode .theremin-hint {
  display: none;
}

/* Permission / status card centred over the pad while air mode is
 * loading, awaiting permission, or recovering from an error. */
.theremin-air-card {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  z-index: 3;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 14px;
  padding: 28px 32px;
  border-radius: 18px;
  background: rgba(15, 23, 42, 0.92);
  border: 1px solid var(--border);
  box-shadow:
    0 24px 60px -20px rgba(0, 0, 0, 0.7),
    inset 0 1px 0 rgba(255, 255, 255, 0.06);
  max-width: min(90%, 380px);
  text-align: center;
  backdrop-filter: blur(8px);
}

.theremin-air-card[hidden] {
  display: none;
}

.theremin-air-card-icon {
  font-size: 36px;
  line-height: 1;
  filter: drop-shadow(0 4px 14px rgba(129, 140, 248, 0.5));
}

.theremin-air-card-title {
  margin: 0;
  font-size: 18px;
  letter-spacing: -0.01em;
  color: var(--fg);
}

.theremin-air-card-message {
  margin: 0;
  color: var(--fg-dim);
  font-size: 13px;
  line-height: 1.5;
}

.theremin-air-card-button {
  margin-top: 4px;
  padding: 10px 20px;
  border-radius: 10px;
  border: 1px solid rgba(255, 255, 255, 0.12);
  background: linear-gradient(135deg, rgba(129, 140, 248, 0.95), rgba(244, 114, 182, 0.95));
  color: #fff;
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.02em;
  cursor: pointer;
  box-shadow: 0 4px 14px rgba(129, 140, 248, 0.35);
  transition:
    transform 160ms ease,
    box-shadow 160ms ease,
    filter 160ms ease;
}

.theremin-air-card-button:hover,
.theremin-air-card-button:focus-visible {
  transform: translateY(-1px);
  box-shadow: 0 8px 18px rgba(244, 114, 182, 0.45);
  outline: none;
  filter: brightness(1.05);
}

.theremin-air-card-button[disabled] {
  cursor: progress;
  filter: grayscale(0.4);
  transform: none;
  box-shadow: none;
}

.theremin-air-card-button[hidden] {
  display: none;
}

@media (prefers-reduced-motion: reduce) {
  .theremin-air-card-button {
    transition: none;
  }
}

@media (max-width: 640px) {
  .theremin-pad {
    height: clamp(300px, 64vh, 520px);
  }
  .theremin-hint {
    font-size: 12px;
    padding: 0 24px;
  }
  .theremin-axis-label {
    font-size: 9px;
  }
  .theremin-air-card {
    padding: 22px 24px;
    gap: 10px;
  }
  .theremin-air-card-message {
    font-size: 12px;
  }
}