/* -------- station floor / cards -------- */

.floor-summary {
  color: var(--text-dim);
  font-weight: 600;
  margin: -1rem 0 1.5rem;
}

.sound-help {
  margin: 0 0 1.5rem;
  color: var(--text-dim);
  font-size: 0.9rem;
}

.sound-help summary {
  cursor: pointer;
  font-weight: 600;
  color: var(--text);
}

.sound-help summary:focus-visible {
  outline: 3px solid #fff;
  outline-offset: 2px;
}

.sound-help ul {
  margin: 0.6rem 0 0;
  padding-left: 1.25rem;
  line-height: 1.6;
}

.floor-section-heading {
  font-family: var(--font-display);
  font-size: 1rem;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--text-dim);
  margin: 2rem 0 1rem;
}

.floor-section-heading:first-of-type {
  margin-top: 0;
}

.station-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 1.25rem;
}

.station-card {
  position: relative;
  display: block;
  text-decoration: none;
  color: var(--text);
  background: var(--bg-raised);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  min-height: 180px;
  transition: transform 0.15s ease, box-shadow 0.15s ease, border-color 0.15s ease;
}

.station-card::before {
  content: "";
  position: absolute;
  inset: 0;
  border-radius: inherit;
  padding: 1px;
  background: linear-gradient(135deg, var(--accent, var(--accent-default)), transparent 60%);
  -webkit-mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
  -webkit-mask-composite: xor;
  mask-composite: exclude;
  opacity: 0.5;
  pointer-events: none;
}

.station-card:hover,
.station-card:focus-visible {
  transform: translateY(-3px);
  border-color: var(--accent, var(--accent-default));
  box-shadow: 0 10px 30px -12px var(--accent, var(--accent-default));
}

.station-card h3 {
  font-family: var(--font-display);
  font-size: 1.5rem;
  margin: 0.4rem 0 0.5rem;
}

.station-card p {
  color: var(--text-dim);
  margin: 0;
  line-height: 1.4;
}

.station-card .badge {
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: #0f1220;
  background: var(--accent, var(--accent-default));
  padding: 0.25rem 0.6rem;
  border-radius: 999px;
}

.station-card .badge-complete {
  background: #6bffb0;
  color: #0f1220;
}

.enter-hint {
  position: absolute;
  bottom: 1.25rem;
  right: 1.5rem;
  color: var(--accent, var(--accent-default));
  font-weight: 600;
}

/* -------- station stage -------- */

.stage-header {
  display: flex;
  align-items: baseline;
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.back-link {
  text-decoration: none;
  color: var(--text-dim);
  font-weight: 600;
}

.back-link:hover {
  color: var(--text);
}

.stage-header h2 {
  font-family: var(--font-display);
  font-size: clamp(1.6rem, 4vw, 2.2rem);
  margin: 0;
  color: var(--accent, var(--accent-default));
}

.stage-body {
  background: var(--bg-raised);
  border-radius: var(--radius-lg);
  padding: clamp(1.25rem, 4vw, 2.5rem);
  border: 1px solid rgba(255, 255, 255, 0.08);
}

.prompt {
  font-size: 1.1rem;
  color: var(--text-dim);
  margin-top: 0;
}

/* -------- shared controls -------- */

.big-readout {
  font-family: var(--font-display);
  font-size: clamp(2.5rem, 8vw, 4.5rem);
  font-weight: 700;
  text-align: center;
  margin: 1rem 0;
  color: var(--accent, var(--accent-default));
  font-variant-numeric: tabular-nums;
}

.big-slider {
  width: 100%;
  height: 3rem;
  -webkit-appearance: none;
  appearance: none;
  background: transparent;
  cursor: pointer;
  margin: 1rem 0;
}

.big-slider::-webkit-slider-runnable-track {
  height: 12px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.15);
}

.big-slider::-moz-range-track {
  height: 12px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.15);
}

.big-slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 34px;
  height: 34px;
  margin-top: -11px;
  border-radius: 50%;
  background: var(--accent, var(--accent-default));
  border: 4px solid #0f1220;
  box-shadow: 0 0 0 2px var(--accent, var(--accent-default));
}

.big-slider::-moz-range-thumb {
  width: 34px;
  height: 34px;
  border-radius: 50%;
  background: var(--accent, var(--accent-default));
  border: 4px solid #0f1220;
  box-shadow: 0 0 0 2px var(--accent, var(--accent-default));
}

.big-slider:focus-visible {
  outline: none;
}

.big-slider:focus-visible::-webkit-slider-thumb {
  outline: 3px solid #fff;
  outline-offset: 2px;
}

.numeric-row {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  justify-content: center;
  margin-bottom: 1rem;
  color: var(--text-dim);
}

.numeric-row input[type="number"] {
  width: 5.5rem;
  font-size: 1.1rem;
  text-align: center;
  padding: 0.5rem 0.4rem;
  border-radius: var(--radius-md);
  border: 1px solid rgba(255, 255, 255, 0.2);
  background: rgba(255, 255, 255, 0.05);
  color: var(--text);
}

.preset-row,
.wave-button-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  justify-content: center;
  margin: 1rem 0;
}

.chip {
  border: 1px solid rgba(255, 255, 255, 0.2);
  background: rgba(255, 255, 255, 0.06);
  color: var(--text);
  border-radius: 999px;
  padding: 0.5rem 1rem;
  font-size: 0.95rem;
  cursor: pointer;
}

.chip:hover {
  border-color: var(--accent, var(--accent-default));
}

.chip.active {
  border-color: var(--accent, var(--accent-default));
  background: color-mix(in srgb, var(--accent, var(--accent-default)) 25%, transparent);
  box-shadow: 0 0 12px -4px var(--accent, var(--accent-default));
}

.wave-btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
  border: 2px solid rgba(255, 255, 255, 0.2);
  background: rgba(255, 255, 255, 0.05);
  color: var(--text);
  border-radius: var(--radius-md);
  padding: 1rem 1.6rem;
  font-size: 1.1rem;
  font-weight: 600;
  cursor: pointer;
  min-width: 7rem;
}

.wave-icon {
  width: 3rem;
  height: 1.5rem;
  color: var(--text-dim);
}

.wave-btn.active .wave-icon {
  color: var(--accent, var(--accent-default));
}

.wave-btn.active {
  border-color: var(--accent, var(--accent-default));
  background: color-mix(in srgb, var(--accent, var(--accent-default)) 20%, transparent);
  box-shadow: 0 0 16px -4px var(--accent, var(--accent-default));
}

.wave-btn:focus-visible,
.chip:focus-visible {
  outline: 3px solid #fff;
  outline-offset: 2px;
}

.vf-example {
  color: var(--text-dim);
  font-size: 0.85em;
}

.reveal {
  text-align: center;
  color: var(--text-dim);
  margin: 0.5rem 0 1.5rem;
}

.reveal strong {
  color: var(--accent, var(--accent-default));
}

.meter-track {
  height: 16px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.1);
  overflow: hidden;
  margin-bottom: 1.5rem;
}

.meter-fill {
  height: 100%;
  width: 70%;
  background: linear-gradient(90deg, var(--accent, var(--accent-default)), #fff);
  transition: width 0.05s linear;
}

.waveform-canvas {
  width: 100%;
  height: 180px;
  display: block;
  border-radius: var(--radius-md);
  background: rgba(0, 0, 0, 0.35);
  border: 1px solid rgba(255, 255, 255, 0.08);
}

@media (max-width: 480px) {
  .wave-btn {
    flex: 1 1 40%;
  }
}

/* -------- octave machine -------- */

.octave-ladder {
  display: flex;
  flex-direction: column-reverse;
  gap: 0.4rem;
  margin: 1.5rem auto;
  max-width: 20rem;
}

.octave-rung {
  text-align: center;
  padding: 0.5rem;
  border-radius: var(--radius-md);
  border: 1px solid rgba(255, 255, 255, 0.1);
  color: var(--text-dim);
  font-variant-numeric: tabular-nums;
  transition: all 0.15s ease;
}

.octave-rung.current {
  border-color: var(--accent, var(--accent-default));
  background: color-mix(in srgb, var(--accent, var(--accent-default)) 18%, transparent);
  color: var(--text);
  font-weight: 700;
  transform: scale(1.04);
}

/* -------- oscillator diagram -------- */

.osc-diagram {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  margin: 0.5rem 0 2rem;
}

.osc-box {
  border: 2px solid rgba(255, 255, 255, 0.2);
  border-radius: var(--radius-md);
  padding: 0.9rem 1.4rem;
  font-family: var(--font-display);
  font-weight: 700;
  letter-spacing: 0.03em;
}

.osc-box-sound {
  border-color: var(--accent, var(--accent-default));
  color: var(--accent, var(--accent-default));
}

.osc-arrow {
  font-size: 1.5rem;
  color: var(--text-dim);
}

.osc-control {
  margin-bottom: 1.5rem;
}

.osc-control-label {
  text-align: center;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  font-size: 0.8rem;
  color: var(--text-dim);
  font-weight: 700;
}

/* -------- compact controls (secondary params on multi-control stations) -------- */
/* .big-readout/.big-slider are sized for one headline control per station — stack
   3-4 of them (EQ's Frequency+Gain+Q, ADSR's four fields) and the page is mostly
   scrolling before any visualization shows. .control-row holds 2+ .control-compact
   items side by side, each with a much smaller readout and slider, so only the
   one control a station is really about gets the full-size treatment. */

.control-row {
  display: flex;
  gap: 1.5rem;
  margin-bottom: 1.5rem;
}

.control-compact {
  flex: 1;
  min-width: 0;
}

.compact-readout {
  font-family: var(--font-display);
  font-size: clamp(1.3rem, 4vw, 1.8rem);
  font-weight: 700;
  text-align: center;
  margin: 0.4rem 0;
  color: var(--accent, var(--accent-default));
  font-variant-numeric: tabular-nums;
}

.compact-slider {
  width: 100%;
  height: 2rem;
  -webkit-appearance: none;
  appearance: none;
  background: transparent;
  cursor: pointer;
  margin: 0.4rem 0;
}

.compact-slider::-webkit-slider-runnable-track {
  height: 8px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.15);
}

.compact-slider::-moz-range-track {
  height: 8px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.15);
}

.compact-slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 24px;
  height: 24px;
  margin-top: -8px;
  border-radius: 50%;
  background: var(--accent, var(--accent-default));
  border: 3px solid #0f1220;
  box-shadow: 0 0 0 2px var(--accent, var(--accent-default));
}

.compact-slider::-moz-range-thumb {
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: var(--accent, var(--accent-default));
  border: 3px solid #0f1220;
  box-shadow: 0 0 0 2px var(--accent, var(--accent-default));
}

.compact-slider:focus-visible {
  outline: none;
}

.compact-slider:focus-visible::-webkit-slider-thumb {
  outline: 3px solid #fff;
  outline-offset: 2px;
}

.compact-slider:focus-visible::-moz-range-thumb {
  outline: 3px solid #fff;
  outline-offset: 2px;
}

@media (max-width: 480px) {
  .control-row {
    flex-direction: column;
    gap: 0;
  }
}

/* -------- frequency x amplitude pad -------- */

.xy-readouts {
  display: flex;
  justify-content: center;
  gap: 2.5rem;
  margin-bottom: 1.25rem;
}

.xy-label {
  display: block;
  text-align: center;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  font-size: 0.75rem;
  color: var(--text-dim);
  font-weight: 700;
}

.xy-value {
  display: block;
  text-align: center;
  font-family: var(--font-display);
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--accent, var(--accent-default));
  font-variant-numeric: tabular-nums;
}

.xy-pad {
  position: relative;
  width: 100%;
  height: min(60vw, 320px);
  border-radius: var(--radius-lg);
  background: linear-gradient(
      to right,
      transparent,
      color-mix(in srgb, var(--accent, var(--accent-default)) 10%, transparent)
    ),
    rgba(0, 0, 0, 0.35);
  border: 1px solid rgba(255, 255, 255, 0.12);
  cursor: crosshair;
  touch-action: none;
}

.xy-pad:focus-visible {
  outline: 3px solid #fff;
  outline-offset: 2px;
}

.xy-grid {
  position: absolute;
  inset: 0;
  border-radius: inherit;
  background-image: linear-gradient(to right, rgba(255, 255, 255, 0.07) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(255, 255, 255, 0.07) 1px, transparent 1px);
  background-size: 25% 25%;
  pointer-events: none;
}

.xy-crosshair {
  position: absolute;
  background: rgba(255, 255, 255, 0.16);
  pointer-events: none;
}

.xy-crosshair-h {
  left: 0;
  right: 0;
  top: 50%;
  height: 1px;
}

.xy-crosshair-v {
  top: 0;
  bottom: 0;
  left: 50%;
  width: 1px;
}

.xy-corner {
  position: absolute;
  font-size: 0.65rem;
  line-height: 1.35;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-dim);
  opacity: 0.65;
  pointer-events: none;
}

.xy-corner-tl {
  top: 0.75rem;
  left: 0.9rem;
}

.xy-corner-tr {
  top: 0.75rem;
  right: 0.9rem;
  text-align: right;
}

.xy-corner-bl {
  bottom: 0.75rem;
  left: 0.9rem;
}

.xy-corner-br {
  bottom: 0.75rem;
  right: 0.9rem;
  text-align: right;
}

.xy-dot {
  position: absolute;
  width: 28px;
  height: 28px;
  margin: -14px;
  border-radius: 50%;
  background: var(--accent-local, var(--accent-default));
  box-shadow: 0 0 0 4px rgba(0, 0, 0, 0.35), 0 0 20px var(--accent-local, var(--accent-default));
  pointer-events: none;
}

.xy-hint {
  position: absolute;
  top: 140%;
  left: 50%;
  transform: translateX(-50%);
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-dim);
  white-space: nowrap;
  animation: xy-hint-pulse 1.6s ease-in-out infinite;
}

@keyframes xy-hint-pulse {
  0%,
  100% {
    opacity: 0.35;
  }
  50% {
    opacity: 1;
  }
}

.challenge-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  justify-content: center;
  margin-top: 1.5rem;
}

.challenge-chip {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  border: 1px solid rgba(255, 255, 255, 0.15);
  border-radius: 999px;
  padding: 0.5rem 1rem;
  color: var(--text-dim);
}

.challenge-chip.achieved {
  border-color: #6bffb0;
  color: var(--text);
}

.challenge-check {
  color: #6bffb0;
  font-weight: 700;
}

/* -------- predict-then-test -------- */

.predict-box {
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: var(--radius-md);
  padding: 1rem 1.25rem;
  margin-bottom: 1.5rem;
}

.predict-question {
  margin: 0 0 0.75rem;
  font-weight: 600;
}

.predict-buttons {
  display: flex;
  gap: 0.6rem;
}

.predict-buttons button:disabled {
  opacity: 0.45;
  cursor: default;
}

.predict-reveal {
  margin: 0.75rem 0 0;
  color: var(--accent, var(--accent-default));
  font-weight: 600;
}

/* -------- harmonics -------- */

.harmonic-bars {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  row-gap: 1rem;
  justify-content: center;
  align-items: flex-end;
  margin: 1.5rem 0;
}

.harmonic-slot {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.4rem;
}

.harmonic-bar {
  width: 36px;
  height: 160px;
  border: 2px solid rgba(255, 255, 255, 0.15);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.04);
  display: flex;
  align-items: flex-end;
  padding: 4px;
  cursor: pointer;
}

.harmonic-bar-fill {
  width: 100%;
  height: var(--bar-height, 20%);
  border-radius: 4px;
  background: rgba(255, 255, 255, 0.18);
  transition: background 0.15s ease, box-shadow 0.15s ease;
}

.harmonic-bar.active .harmonic-bar-fill {
  background: var(--accent, var(--accent-default));
  box-shadow: 0 0 14px -2px var(--accent, var(--accent-default));
}

.harmonic-bar.locked {
  cursor: default;
  border-color: var(--accent, var(--accent-default));
}

.harmonic-bar.locked .harmonic-bar-fill {
  background: var(--accent, var(--accent-default));
}

.harmonic-bar:disabled {
  opacity: 1;
}

.harmonic-bar:focus-visible {
  outline: 3px solid #fff;
  outline-offset: 2px;
}

.harmonic-bar-label {
  font-size: 0.8rem;
  color: var(--text-dim);
  font-weight: 600;
}

@media (max-width: 480px) {
  .harmonic-bars {
    gap: 0.3rem;
  }

  .harmonic-bar {
    width: 26px;
    height: 130px;
  }

  .harmonic-bar-label {
    font-size: 0.7rem;
  }
}

/* -------- finish / receipt -------- */

.reflection-label {
  display: block;
  font-weight: 600;
  margin: 1.5rem 0 0.5rem;
}

.reflection-label:first-of-type {
  margin-top: 0;
}

.reflection-input {
  width: 100%;
  border-radius: var(--radius-md);
  border: 1px solid rgba(255, 255, 255, 0.2);
  background: rgba(255, 255, 255, 0.05);
  color: var(--text);
  padding: 0.75rem;
  font-family: inherit;
  font-size: 1rem;
  resize: vertical;
}

.reflection-input:focus-visible {
  outline: 3px solid #fff;
  outline-offset: 2px;
}

#generate-btn {
  margin: 1.5rem 0;
}

.receipt-summary {
  color: var(--text);
  font-weight: 600;
  margin: 0 0 0.75rem;
}

.receipt-block {
  background: rgba(0, 0, 0, 0.35);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: var(--radius-md);
  padding: 1.25rem;
  white-space: pre-wrap;
  word-break: break-all;
  font-family: ui-monospace, "SFMono-Regular", Menlo, monospace;
  font-size: 0.85rem;
  line-height: 1.5;
  margin: 0 0 1rem;
  max-height: 420px;
  overflow-y: auto;
}

.copy-status {
  color: var(--accent, var(--accent-default));
  font-weight: 600;
  min-height: 1.2em;
}

.receipt-disclaimer {
  color: var(--text-dim);
  font-size: 0.85rem;
  margin-top: 1rem;
  line-height: 1.5;
}

/* -------- dBFS / dB SPL -------- */

.spl-chart {
  margin-top: 2rem;
  padding-top: 1.5rem;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.spl-chart-title {
  font-family: var(--font-display);
  font-size: 1.1rem;
  margin: 0 0 0.75rem;
  color: var(--accent, var(--accent-default));
}

.spl-chart-note {
  color: var(--text-dim);
  font-size: 0.9rem;
  line-height: 1.6;
  margin: 0 0 1.25rem;
}

.spl-stage {
  min-height: 8.5rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  gap: 0.75rem;
  padding: 1rem;
  margin-bottom: 1.25rem;
  border-radius: var(--radius-lg);
  background: rgba(0, 0, 0, 0.3);
  border: 1px solid rgba(255, 255, 255, 0.08);
}

.spl-stage-placeholder {
  color: var(--text-dim);
  margin: 0;
}

.spl-swarm {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 0.15em;
  line-height: 1;
}

.spl-swarm span {
  font-size: var(--emoji-size, 1.5rem);
  line-height: 1;
}

.spl-stage-caption {
  color: var(--text-dim);
  font-size: 0.85rem;
  margin: 0;
}

.spl-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.spl-item {
  width: 100%;
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.6rem 0.9rem;
  border-radius: var(--radius-md);
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid rgba(255, 255, 255, 0.08);
  color: var(--text);
  cursor: pointer;
  font-family: inherit;
  font-size: 1rem;
  text-align: left;
}

.spl-item-emoji {
  font-size: 1.3rem;
  line-height: 1;
}

.spl-item-label {
  flex: 1;
}

.spl-item-value {
  color: var(--text-dim);
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
}

.spl-item:hover {
  border-color: var(--accent, var(--accent-default));
}

.spl-item.active {
  border-color: var(--accent, var(--accent-default));
  background: color-mix(in srgb, var(--accent, var(--accent-default)) 16%, transparent);
}

.spl-item.active .spl-item-value {
  color: var(--text);
}

.spl-item:focus-visible {
  outline: 3px solid #fff;
  outline-offset: 2px;
}

.spl-divider {
  padding: 0.6rem 0.9rem;
  border-radius: var(--radius-md);
  background: rgba(255, 200, 100, 0.08);
  border: 1px dashed rgba(255, 200, 100, 0.4);
  color: var(--text-dim);
  font-size: 0.85rem;
  line-height: 1.5;
}

/* -------- periodic vs aperiodic -------- */

.periodic-status {
  display: block;
  width: fit-content;
  margin: 0 auto 1.5rem;
  padding: 0.35rem 0.9rem;
  border-radius: 999px;
  font-weight: 700;
  font-size: 0.85rem;
  letter-spacing: 0.03em;
  text-transform: uppercase;
  color: #0f1220;
  background: var(--accent, var(--accent-default));
}

.periodic-status.aperiodic {
  color: var(--text-dim);
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.15);
}

#zoom-label {
  font-weight: 600;
  color: var(--text);
}

.periodic-definitions {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  margin-top: 2rem;
}

.periodic-def-card {
  border-radius: var(--radius-md);
  padding: 1rem 1.1rem;
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid rgba(255, 255, 255, 0.08);
}

.periodic-def-card h3 {
  font-family: var(--font-display);
  margin: 0 0 0.6rem;
  color: var(--accent, var(--accent-default));
  font-size: 1rem;
}

.periodic-def-card-noise h3 {
  color: var(--text-dim);
}

.periodic-def-card ul {
  margin: 0;
  padding-left: 1.1rem;
  color: var(--text-dim);
  font-size: 0.9rem;
  line-height: 1.6;
}

@media (max-width: 480px) {
  .periodic-definitions {
    grid-template-columns: 1fr;
  }
}

/* -------- spectrum analyzer -------- */

.spectrum-canvas {
  width: 100%;
  height: 220px;
  display: block;
  border-radius: var(--radius-md);
  background: rgba(0, 0, 0, 0.35);
  border: 1px solid rgba(255, 255, 255, 0.08);
}

.spectrum-canvas[hidden] {
  display: none;
}

.spectrum-axis {
  position: relative;
  height: 1.4rem;
  margin-top: 0.4rem;
}

.spectrum-axis span {
  position: absolute;
  top: 0;
  transform: translateX(-50%);
  color: var(--text-dim);
  font-size: 0.75rem;
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
}

.spectrum-axis span:first-child {
  transform: translateX(0);
}

.spectrum-axis span:last-child {
  transform: translateX(-100%);
}

/* A spectrogram's frequency axis is vertical (its horizontal axis is
   time, which scrolls and isn't calibrated with fixed labels) — this is
   deliberately a different layout from .spectrum-axis above, not a
   sideways reuse of it. */
.spectrogram-row {
  display: flex;
  align-items: stretch;
  gap: 0.5rem;
}

.spectrogram-row[hidden] {
  display: none;
}

.spectrogram-row .spectrum-canvas {
  flex: 1 1 auto;
  min-width: 0;
}

.spectrogram-freq-axis {
  position: relative;
  flex: 0 0 3.4rem;
}

.spectrogram-freq-axis span {
  position: absolute;
  right: 0.4rem;
  transform: translateY(-50%);
  color: var(--text-dim);
  font-size: 0.75rem;
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
}

.filter-shape-badge {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.6rem;
  color: var(--accent, var(--accent-default));
  font-weight: 700;
  margin: 0 0 1.25rem;
}

.filter-shape-badge .wave-icon {
  width: 2.2rem;
  height: 1.1rem;
  color: inherit;
}

.pulse-section {
  margin-top: 1.5rem;
}

.pulse-section:first-of-type {
  margin-top: 0.5rem;
}

/* -------- what is sound (longitudinal/transverse) -------- */

.sw-section {
  margin-top: 1.5rem;
}

.sw-section:first-of-type {
  margin-top: 1rem;
}

.particle-canvas {
  width: 100%;
  height: 120px;
  display: block;
  border-radius: var(--radius-md);
  background: rgba(0, 0, 0, 0.35);
  border: 1px solid rgba(255, 255, 255, 0.08);
}

.sw-caption {
  text-align: center;
  color: var(--text-dim);
  font-size: 0.85rem;
  margin: 0.6rem 0 0;
}

/* -------- colors of noise -------- */

.color-button-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  justify-content: center;
  margin: 1rem 0;
}

.color-btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.4rem;
  border: 2px solid rgba(255, 255, 255, 0.2);
  background: rgba(255, 255, 255, 0.05);
  color: var(--text);
  border-radius: var(--radius-md);
  padding: 0.8rem 1.2rem;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
}

.color-btn .wave-icon {
  color: var(--swatch, var(--text-dim));
}

.color-btn.active {
  border-color: var(--swatch, var(--accent-default));
  background: color-mix(in srgb, var(--swatch, var(--accent-default)) 18%, transparent);
  box-shadow: 0 0 14px -2px var(--swatch, var(--accent-default));
}

.color-btn:focus-visible {
  outline: 3px solid #fff;
  outline-offset: 2px;
}

.color-note {
  text-align: center;
  font-weight: 600;
  margin: 0.5rem 0 1.5rem;
  min-height: 1.4em;
}

/* -------- phase/polarity/interference family -------- */

.pp-section {
  margin-top: 1.25rem;
}

.pp-section:first-of-type {
  margin-top: 1rem;
}

.pp-canvas {
  height: 90px;
}

.pp-label-a {
  color: #7ce0ff;
}

.pp-label-b {
  color: #ff9b7c;
}

/* -------- polarity -------- */

.polarity-toggle {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  margin: 0 auto 1rem;
}

.polarity-icon {
  display: inline-block;
  font-size: 1.1rem;
  line-height: 1;
  transition: transform 0.4s ease;
}

.polarity-icon.flipped {
  transform: rotate(180deg);
}

.polarity-state {
  text-align: center;
  font-weight: 700;
  color: var(--text-dim);
  margin: 0 0 1.5rem;
}

.polarity-state.inverted {
  color: var(--accent, var(--accent-default));
}

.polarity-note {
  color: var(--text-dim);
  font-size: 0.85rem;
  line-height: 1.6;
  margin-top: 1.25rem;
}

/* -------- beating -------- */

.beat-freqs {
  text-align: center;
  color: var(--text-dim);
  font-variant-numeric: tabular-nums;
  margin: -0.5rem 0 1.5rem;
}

/* -------- spectrogram -------- */

.sg-freq-control {
  margin: 1rem 0;
}

.sg-freq-control[hidden] {
  display: none;
}

/* -------- fft -------- */

.fft-pair {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  margin-top: 1.5rem;
}

.fft-pane .waveform-canvas,
.fft-pane .spectrum-canvas {
  height: 140px;
}

.fft-section {
  margin-top: 2rem;
  padding-top: 1.5rem;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.fft-caption {
  color: var(--text-dim);
  font-size: 0.9rem;
  line-height: 1.6;
  margin: 0.5rem 0 1.25rem;
}

@media (max-width: 600px) {
  .fft-pair {
    grid-template-columns: 1fr;
  }
}

/* -------- ADSR note pad -------- */

.note-pad {
  display: block;
  width: 100%;
  max-width: 280px;
  margin: 0.5rem auto 1.5rem;
  padding: 1.75rem 1rem;
  font-size: 1.15rem;
  font-weight: 700;
  text-align: center;
  border-radius: var(--radius-md);
  border: 2px solid rgba(255, 255, 255, 0.2);
  background: rgba(255, 255, 255, 0.05);
  color: var(--text);
  cursor: pointer;
  touch-action: none;
  user-select: none;
  -webkit-user-select: none;
  transition: transform 0.08s ease, background 0.08s ease, border-color 0.08s ease,
    box-shadow 0.08s ease;
}

.note-pad:hover {
  border-color: var(--accent, var(--accent-default));
}

.note-pad:focus-visible {
  outline: 3px solid #fff;
  outline-offset: 2px;
}

.note-pad.held {
  transform: scale(0.97);
  border-color: var(--accent, var(--accent-default));
  background: color-mix(in srgb, var(--accent, var(--accent-default)) 30%, transparent);
  box-shadow: 0 0 24px -4px var(--accent, var(--accent-default));
}

/* -------- additive vs. subtractive (A/B pane picker) -------- */

.ab-pane-header {
  display: block;
  width: 100%;
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: var(--radius-md);
  padding: 0.6rem 0.75rem;
  margin-bottom: 1rem;
  font: inherit;
  text-align: center;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--text-dim);
  cursor: pointer;
  transition: color 0.2s ease, background 0.2s ease, border-color 0.2s ease;
}

.ab-pane-header:hover {
  border-color: var(--accent, var(--accent-default));
}

.ab-pane-header:focus-visible {
  outline: 3px solid #fff;
  outline-offset: 2px;
}

.ab-pane-dot {
  display: inline-block;
  width: 0.45rem;
  height: 0.45rem;
  border-radius: 50%;
  background: currentColor;
  opacity: 0.35;
  margin-right: 0.5rem;
  vertical-align: middle;
}

.ab-pane.active .ab-pane-header {
  color: var(--accent, var(--accent-default));
  background: color-mix(in srgb, var(--accent, var(--accent-default)) 16%, transparent);
  border-color: var(--accent, var(--accent-default));
}

.ab-pane.active .ab-pane-dot {
  opacity: 1;
  box-shadow: 0 0 6px currentColor;
}

/* The silent pane stays interactive (its own controls still switch to it —
   see js) but reads clearly as "not what you're hearing right now". */
.ab-pane:not(.active) .ab-pane-body {
  opacity: 0.4;
  filter: saturate(0.4);
  transition: opacity 0.25s ease, filter 0.25s ease;
}

.ab-pane.active .ab-pane-body {
  opacity: 1;
  filter: none;
  transition: opacity 0.25s ease, filter 0.25s ease;
}