/* ============================================================================
 * Music Train — styles
 * Clean educational tone; no animations beyond correct/wrong flash.
 * Auto light/dark via prefers-color-scheme.
 * ========================================================================= */

:root {
  --bg-primary: #f5f5f7;
  --bg-secondary: #ffffff;
  --bg-tertiary: #ececef;
  --border: #d8d8db;
  --text-primary: #1d1d1f;
  --text-secondary: #5c5c63;
  --text-tertiary: #8e8e93;
  --accent: #0066d4;
  --accent-soft: #e8f1fd;
  --accent-strong: #004ea1;
  --ok: #2da44e;
  --ok-soft: #e6f4ea;
  --warn: #d97706;
  --error: #d33b3b;
  --error-soft: #fbeaea;
  --staff-bg: #ffffff;
  --staff-ink: #1d1d1f;
  --radius: 10px;
  --shadow: 0 1px 2px rgba(0, 0, 0, 0.04), 0 1px 6px rgba(0, 0, 0, 0.04);
  --mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg-primary: #181819;
    --bg-secondary: #232325;
    --bg-tertiary: #2c2c2e;
    --border: #3a3a3d;
    --text-primary: #ececec;
    --text-secondary: #b0b0b6;
    --text-tertiary: #76767c;
    --accent: #4a9eff;
    --accent-soft: rgba(74, 158, 255, 0.16);
    --accent-strong: #7dbcff;
    --ok: #4cc879;
    --ok-soft: rgba(76, 200, 121, 0.18);
    --warn: #e1a04a;
    --error: #ff5b5b;
    --error-soft: rgba(255, 91, 91, 0.16);
  }
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html, body {
  height: 100%;
  background: var(--bg-primary);
  color: var(--text-primary);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, sans-serif;
  font-size: 14.5px;
  line-height: 1.5;
}

body {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.7rem 1.4rem;
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
}
.brand {
  font-weight: 600;
  font-size: 1.05rem;
  letter-spacing: -0.01em;
  cursor: pointer;
}
.topnav { display: flex; gap: 0.4rem; }
.navlink {
  background: transparent;
  border: 1px solid transparent;
  color: var(--text-secondary);
  font: inherit;
  padding: 0.35rem 0.75rem;
  border-radius: 6px;
  cursor: pointer;
}
.navlink:hover { background: var(--bg-tertiary); color: var(--text-primary); }
.navlink.active { background: var(--accent-soft); color: var(--accent); border-color: var(--accent); }

main#screen-root {
  flex: 1;
  width: 100%;
  max-width: 1180px;
  margin: 0 auto;
  padding: 1.6rem 1.4rem 3rem;
}

.footbar {
  padding: 0.7rem 1.4rem;
  background: var(--bg-secondary);
  border-top: 1px solid var(--border);
  font-size: 0.78rem;
  color: var(--text-tertiary);
  flex-shrink: 0;
}
.footbar code { font-family: var(--mono); background: var(--bg-tertiary); padding: 0.05em 0.3em; border-radius: 3px; }

.loading {
  text-align: center;
  padding: 4rem 1rem;
  color: var(--text-secondary);
}
.spin {
  display: inline-block;
  width: 0.9em; height: 0.9em;
  border: 2px solid var(--text-tertiary);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
  vertical-align: middle;
  margin-right: 0.4em;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* ===== HOME / LEVEL SELECT ===== */
.screen-title { font-size: 1.4rem; font-weight: 600; margin-bottom: 0.3rem; }
.screen-subtitle { color: var(--text-secondary); margin-bottom: 1.5rem; font-size: 0.92rem; }

.tier { margin-bottom: 1.4rem; }
.tier-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 0.6rem;
  flex-wrap: wrap;
  gap: 0.6rem;
}
.tier-titleblock { display: flex; flex-direction: column; gap: 0.1rem; }
.tier-title { font-weight: 600; font-size: 0.95rem; }
.tier-goal { color: var(--text-tertiary); font-size: 0.8rem; }

.tier-key-picker {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  padding: 0.3rem 0.55rem;
  border-radius: 7px;
}
.tier-key-label {
  font-size: 0.72rem;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  font-weight: 600;
}
.tier-key-select {
  background: var(--bg-tertiary);
  border: 1px solid var(--border);
  border-radius: 5px;
  padding: 0.3rem 0.5rem;
  font: inherit;
  font-size: 0.88rem;
  color: var(--text-primary);
  cursor: pointer;
  min-width: 7rem;
}
.tier-key-select:focus { outline: none; border-color: var(--accent); }

/* Inline key-picker that lives ON the L2 level card (Intervals "Select the
   key" affordance). Same visual language as .tier-key-select but sized to
   fit inside the card, and explicitly above the stats / progress rows. */
.lvl-keypicker-row {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  margin: 0.15rem 0 0.05rem;
}
.lvl-key-select {
  background: var(--bg-tertiary);
  border: 1px solid var(--border);
  border-radius: 5px;
  padding: 0.3rem 0.45rem;
  font: inherit;
  font-size: 0.88rem;
  color: var(--text-primary);
  cursor: pointer;
  width: 100%;
}
.lvl-key-select:focus { outline: none; border-color: var(--accent); }

/* Inline amber warning shown on incomplete-submit (a required blank is
   still empty). Auto-fades; doesn't affect accuracy. */
.incomplete-warning {
  background: var(--bg-secondary);
  border: 1px solid var(--warn);
  color: var(--warn);
  border-radius: 6px;
  padding: 0.55rem 0.9rem;
  margin: 0.7rem auto 0;
  max-width: 580px;
  text-align: center;
  font-size: 0.92rem;
  font-weight: 500;
  box-shadow: 0 0 0 4px rgba(217, 119, 6, 0.10);
}
.incomplete-warning.show {
  animation: incomplete-warn-pop 0.22s ease-out;
}
@keyframes incomplete-warn-pop {
  0%   { transform: translateY(-6px); opacity: 0; }
  100% { transform: translateY(0);    opacity: 1; }
}

/* ====================================================================
 * Piano keyboard widget (used by every piano-mode drill)
 * ==================================================================== */
.pk-root {
  width: 100%;
  max-width: 720px;
  margin: 0 auto;
}
.pk-shifter {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.6rem;
  margin-bottom: 0.45rem;
  font-size: 0.86rem;
}
.pk-shift-btn {
  background: var(--bg-tertiary);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 0.3rem 0.65rem;
  color: var(--text-primary);
  cursor: pointer;
  font: inherit;
  font-size: 0.82rem;
}
.pk-shift-btn:hover:not(:disabled) { border-color: var(--accent); color: var(--accent); }
.pk-shift-btn:disabled { opacity: 0.4; cursor: not-allowed; }
.pk-range-label {
  font-family: var(--mono);
  color: var(--text-secondary);
  min-width: 5rem;
  text-align: center;
}
.pk-svg {
  width: 100%;
  height: auto;
  display: block;
  user-select: none;
  -webkit-tap-highlight-color: transparent;
  touch-action: manipulation;
}
.pk-key {
  cursor: pointer;
  transition: fill 0.05s linear;
}
.pk-key-white {
  fill: #fbfbfb;
  stroke: #555;
  stroke-width: 1;
}
.pk-key-black {
  fill: #1a1a1c;
  stroke: #000;
  stroke-width: 1;
}
.pk-key-white:hover { fill: #eaf1fa; }
.pk-key-black:hover { fill: #3a3a3e; }
.pk-key.pk-tap         { fill: var(--accent); }
.pk-key-black.pk-tap   { fill: var(--accent-strong); }
.pk-disabled .pk-key   { pointer-events: none; cursor: default; }
.pk-disabled .pk-key-white:hover { fill: #fbfbfb; }
.pk-disabled .pk-key-black:hover { fill: #1a1a1c; }

.pk-key-label {
  fill: var(--text-tertiary);
  font-family: var(--mono);
  font-size: 11px;
  pointer-events: none;
}

/* Red-dot stimulus marker. Drawn above keys; ignored for pointer events. */
.pk-marker-dot {
  fill: var(--error);
  stroke: #500;
  stroke-width: 0.6;
  pointer-events: none;
}
/* Tonic indicator — small red down-pointing triangle above the key. */
.pk-marker-arrow {
  fill: var(--error);
  stroke: #500;
  stroke-width: 0.6;
  pointer-events: none;
}

@media (prefers-color-scheme: dark) {
  .pk-key-white       { fill: #d8d8de; stroke: #777; }
  .pk-key-white:hover { fill: #b9d2ee; }
  .pk-key-black       { fill: #0a0a0a; stroke: #444; }
  .pk-key-black:hover { fill: #303034; }
}

/* ====================================================================
 * Piano session screens — chip display, prompt label, play actions
 * ==================================================================== */
.piano-host {
  margin: 0.5rem auto;
  max-width: 720px;
}
.piano-chips {
  margin: 0.6rem auto;
  max-width: 720px;
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.25rem;
  justify-content: center;
  min-height: 1.6rem;
}
.piano-chip {
  display: inline-block;
  background: var(--accent-soft);
  color: var(--accent);
  border-radius: 4px;
  padding: 0.18rem 0.55rem;
  font-family: var(--mono);
  font-size: 0.92rem;
  font-weight: 600;
}
.piano-chip-dash { color: var(--text-tertiary); font-family: var(--mono); }
.piano-chip-empty { color: var(--text-tertiary); font-style: italic; font-size: 0.84rem; }

.piano-play-actions {
  display: flex;
  gap: 0.45rem;
  align-items: center;
  justify-content: center;
  margin: 0.6rem auto;
  flex-wrap: wrap;
}
.piano-entered-label {
  font-family: var(--mono);
  color: var(--text-secondary);
  font-size: 0.92rem;
  margin-right: 0.6rem;
}

/* ====================================================================
 * Full-spelling keypad (Key & Scale Tier 4 piano session)
 * ==================================================================== */
.fskpad {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0.85rem 1rem;
  max-width: 540px;
  margin: 0.5rem auto;
}
.fskpad-section-label {
  font-size: 0.78rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-secondary);
  margin: 0.4rem 0 0.3rem;
}
.fskpad-pc-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0.35rem;
}
.fskpad-mode-row {
  display: flex;
  gap: 0.5rem;
}
.fskpad-mode-row .fskpad-btn { flex: 1; }
.fskpad-btn {
  background: var(--bg-primary);
  border: 1px solid var(--border);
  color: var(--text-primary);
  border-radius: 6px;
  padding: 0.5rem 0.55rem;
  font: inherit;
  font-size: 0.92rem;
  font-weight: 500;
  cursor: pointer;
  text-align: center;
  transition: background 0.08s ease, border-color 0.08s ease;
}
.fskpad-btn:hover:not(.selected) { border-color: var(--accent); }
.fskpad-btn.selected {
  background: var(--accent);
  border-color: var(--accent);
  color: white;
}
.fskpad-submit-row {
  display: flex;
  justify-content: flex-end;
  margin-top: 0.7rem;
}
.fskpad-submit-row .btn[disabled] {
  opacity: 0.45;
  cursor: not-allowed;
}

.tier-subgroup { margin-top: 0.7rem; }
.subgroup-label {
  font-size: 0.78rem;
  color: var(--text-secondary);
  margin-bottom: 0.4rem;
  padding-left: 0.15rem;
  letter-spacing: 0.02em;
  font-weight: 500;
}

.level-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 0.7rem;
}

.level-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0.85rem 1rem;
  cursor: pointer;
  transition: border-color 0.12s ease, transform 0.06s ease;
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
}
.level-card:hover { border-color: var(--accent); }
.level-card .lvl-id { font-family: var(--mono); font-size: 0.78rem; color: var(--text-tertiary); }
.level-card .lvl-name { font-weight: 500; font-size: 0.92rem; }
.level-card .lvl-stat { font-size: 0.78rem; color: var(--text-secondary); margin-top: 0.4rem; }
.level-card .lvl-stat b { color: var(--accent); }
.level-card .progress {
  height: 3px;
  background: var(--bg-tertiary);
  border-radius: 2px;
  overflow: hidden;
  margin-top: 0.5rem;
}
.level-card .progress > div { height: 100%; background: var(--accent); border-radius: 2px; }

.level-card.expanded {
  border-color: var(--accent);
  box-shadow: var(--shadow);
}
.level-card .start-strip {
  display: none;
  border-top: 1px solid var(--border);
  margin: 0.5rem -1rem -0.85rem;
  padding: 0.7rem 1rem 0.85rem;
  gap: 0.5rem;
}
.level-card.expanded .start-strip { display: flex; }

.btn {
  background: var(--accent);
  color: white;
  border: none;
  font: inherit;
  font-weight: 500;
  padding: 0.45rem 0.95rem;
  border-radius: 6px;
  cursor: pointer;
}
.btn:hover { background: var(--accent-strong); }
.btn.secondary {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text-primary);
}
.btn.secondary:hover { background: var(--bg-tertiary); border-color: var(--accent); }
.btn.danger { background: var(--error); }
.btn.danger:hover { background: #b62929; }

/* ===== CUSTOM CONFIG ===== */
.config-form {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.2rem 1.4rem;
  margin-bottom: 1rem;
}
.field-group { margin-bottom: 1rem; }
.field-group .label { font-weight: 500; font-size: 0.85rem; margin-bottom: 0.4rem; display: block; }
.field-group .description { font-size: 0.8rem; color: var(--text-secondary); margin-bottom: 0.5rem; }
.checkbox-row { display: flex; flex-wrap: wrap; gap: 0.5rem; }
.checkbox-row label {
  display: inline-flex; align-items: center; gap: 0.35rem;
  padding: 0.3rem 0.7rem;
  background: var(--bg-tertiary);
  border-radius: 5px;
  cursor: pointer;
  font-size: 0.85rem;
  user-select: none;
}
.checkbox-row label.checked { background: var(--accent-soft); color: var(--accent); }
.range-row { display: flex; align-items: center; gap: 0.6rem; }
.range-row input[type=number] {
  width: 60px;
  padding: 0.3rem;
  border: 1px solid var(--border);
  border-radius: 5px;
  background: var(--bg-tertiary);
  color: var(--text-primary);
  font: inherit;
}
.config-info { color: var(--text-tertiary); font-size: 0.82rem; margin-top: 0.5rem; }

/* ===== AUDIO CONTROLS (header popover) ===== */
.audio-controls-wrap { position: relative; display: inline-block; }
.audio-trigger { font-size: 1.05rem; }
.audio-trigger.muted { opacity: 0.55; }
.audio-popover {
  position: absolute;
  top: 100%;
  right: 0;
  margin-top: 0.4rem;
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 0.85rem 1rem;
  box-shadow: var(--shadow);
  min-width: 270px;
  z-index: 100;
  display: none;
}
.audio-popover.open { display: block; }
.audio-popover .pop-header {
  font-weight: 600;
  font-size: 0.9rem;
  margin-bottom: 0.6rem;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}
.audio-popover .pop-row {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 0.55rem;
  font-size: 0.88rem;
}
.audio-popover .pop-toggle { cursor: pointer; }
.audio-popover .pop-toggle input { margin: 0; }
.audio-popover .pop-label { min-width: 4.2rem; color: var(--text-secondary); }
.audio-popover input[type='range'] { flex: 1; }
.audio-popover .pop-readout { min-width: 2.6rem; text-align: right; font-family: var(--mono); font-size: 0.82rem; color: var(--text-secondary); }
.audio-popover .pop-status {
  font-size: 0.75rem;
  color: var(--text-tertiary);
  margin-top: 0.4rem;
  padding-top: 0.4rem;
  border-top: 1px solid var(--border);
}
.audio-popover select.instrument-select {
  flex: 1;
  background: var(--bg-tertiary);
  border: 1px solid var(--border);
  border-radius: 5px;
  padding: 0.32rem 0.45rem;
  font: inherit;
  font-size: 0.85rem;
  color: var(--text-primary);
  cursor: pointer;
}
.audio-popover select.instrument-select:focus {
  outline: none;
  border-color: var(--accent);
}
.audio-popover .pop-diag {
  font-family: var(--mono);
  font-size: 0.7rem;
  color: var(--text-tertiary);
  margin-top: 0.35rem;
  padding-top: 0.35rem;
  border-top: 1px dashed var(--border);
  line-height: 1.5;
}

/* ===== REPLAY BUTTON ===== */
.audio-row {
  display: flex;
  justify-content: center;
  margin: -0.4rem 0 0.8rem;
}
.replay-btn { padding: 0.45rem 1rem; font-size: 0.9rem; }

/* ===== KEYPAD ===== */
.kpad-host { display: flex; justify-content: center; }
.kpad {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 0.9rem 1rem;
  max-width: 640px;
  width: 100%;
  margin-top: 0.6rem;
}
.kpad.disabled { opacity: 0.55; pointer-events: none; }

.kpad-rows { display: flex; flex-direction: column; gap: 0.45rem; margin-bottom: 0.85rem; }
.kpad-row {
  display: grid;
  grid-template-columns: 7rem 1fr;
  gap: 0.55rem;
  align-items: center;
  padding: 0.5rem 0.65rem;
  background: var(--bg-tertiary);
  border-radius: 8px;
  border: 2px solid transparent;
  cursor: pointer;
}
.kpad-row.active { border-color: var(--accent); background: var(--accent-soft); }
.kpad-row-label { font-size: 0.83rem; color: var(--text-secondary); text-align: right; font-weight: 500; }
.kpad-display {
  font-family: var(--mono);
  font-size: 1.15rem;
  letter-spacing: 0.02em;
  min-height: 1.55rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.25rem;
  align-items: center;
}
.kpad-chip {
  display: inline-block;
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: 5px;
  padding: 0.05rem 0.45rem;
  font-weight: 600;
  color: var(--text-primary);
}
.kpad-chip.partial {
  border-style: dashed;
  color: var(--accent);
}
.kpad-dash {
  font-family: var(--mono);
  color: var(--text-tertiary);
  font-weight: 500;
}
.kpad-placeholder {
  color: var(--text-tertiary);
  font-style: italic;
  font-size: 0.9rem;
}

.kpad-digits {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  gap: 0.4rem;
  margin-bottom: 0.5rem;
}
@media (max-width: 640px) {
  .kpad-digits { grid-template-columns: repeat(4, 1fr); }
}

.kpad-controls {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  align-items: stretch;
}
.kpad-sep { flex: 0 0 0.5rem; }

.kpad-btn {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: 8px;
  font: inherit;
  font-size: 1.25rem;
  font-weight: 600;
  padding: 0.7rem 0.4rem;
  cursor: pointer;
  color: var(--text-primary);
  min-height: 48px;
  flex: 1;
  user-select: none;
  -webkit-tap-highlight-color: transparent;
  transition: transform 0.05s ease, border-color 0.1s ease, background 0.1s ease;
}
.kpad-btn:hover { border-color: var(--accent); }
.kpad-btn:active { transform: scale(0.97); background: var(--accent-soft); }

.kpad-btn.kpad-mod      { color: var(--accent); font-size: 1.4rem; }
.kpad-btn.kpad-bksp     { font-size: 1.3rem; min-width: 60px; }
.kpad-btn.kpad-nextrow  { font-size: 0.95rem; }
.kpad-btn.kpad-submit, .kpad-btn.primary {
  background: var(--accent);
  color: white;
  border-color: var(--accent);
  font-size: 1rem;
  min-width: 130px;
  flex: 2;
}
.kpad-btn.kpad-submit:hover, .kpad-btn.primary:hover { background: var(--accent-strong); }

.kpad-hint {
  margin-top: 0.7rem;
  font-size: 0.74rem;
  color: var(--text-tertiary);
  text-align: center;
}
@media (max-width: 640px) {
  .kpad-hint { display: none; }
  .kpad-row { grid-template-columns: 5rem 1fr; }
}

/* ===== SESSION SCREEN ===== */
.session-header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  margin-bottom: 1rem;
}
.session-header .lvl-label { font-weight: 600; font-size: 1.05rem; }
.session-header .progress-label {
  background: var(--accent-soft);
  color: var(--accent);
  font-family: var(--mono);
  font-weight: 700;
  font-size: 1rem;
  padding: 0.3rem 0.7rem;
  border-radius: 6px;
  min-width: 3.6rem;
  text-align: center;
  letter-spacing: 0.02em;
}

.staff-panel {
  background: var(--staff-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1rem;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 240px;
  margin-bottom: 1rem;
}
.staff-panel svg text { fill: var(--staff-ink) !important; }
.staff-panel svg path:not([fill="none"]) { fill: var(--staff-ink); }

.input-stack { display: flex; flex-direction: column; gap: 0.55rem; max-width: 460px; margin: 0 auto; }
.input-row { display: grid; grid-template-columns: 6rem 1fr; gap: 0.6rem; align-items: center; }
.input-row .label { font-size: 0.85rem; color: var(--text-secondary); text-align: right; }
.input-row input {
  font: inherit;
  font-family: var(--mono);
  font-size: 1.05rem;
  padding: 0.55rem 0.8rem;
  border: 2px solid var(--border);
  border-radius: 6px;
  background: var(--bg-secondary);
  color: var(--text-primary);
  letter-spacing: 0.02em;
}
.input-row input:focus { outline: none; border-color: var(--accent); }

.session-controls {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: 1rem;
  gap: 1rem;
  max-width: 640px;
  margin-left: auto;
  margin-right: auto;
}
.timer {
  font-family: var(--mono);
  font-size: 1rem;
  color: var(--text-secondary);
}
.timer b { color: var(--text-primary); }

.reveal-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1rem 1.25rem;
  margin-top: 1rem;
  max-width: 580px;
  margin-left: auto;
  margin-right: auto;
}
/* Positive variant shown after a correct submission — same shape as the
   wrong-answer reveal but green-tinted so the user can see at a glance
   whether they got it right. */
.reveal-card.correct {
  background: var(--ok-soft);
  border-color: var(--ok);
}
.reveal-card .reveal-title.correct {
  color: var(--ok);
}

/* ===== Start overlay (before a session begins) ===== */
.start-overlay {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 4rem 1rem 5rem;
  gap: 1rem;
  text-align: center;
}
.start-overlay .start-message {
  font-size: 1.1rem;
  color: var(--text-primary);
  font-weight: 500;
}
.start-overlay .start-sub {
  font-size: 0.9rem;
  color: var(--text-tertiary);
  max-width: 30rem;
}
.btn.big-start-btn {
  font-size: 1.4rem;
  padding: 1rem 2.4rem;
  border-radius: 999px;
  min-width: 12rem;
  box-shadow: 0 4px 14px rgba(0, 102, 212, 0.25);
}
.btn.big-start-btn:hover { transform: translateY(-1px); }

/* ===== Paused state ===== */
body.session-paused .timer { color: var(--warn); }
body.session-paused .staff-panel { opacity: 0.55; }
body.session-paused .audio-row { opacity: 0.55; }
.reveal-card .reveal-title { font-weight: 600; font-size: 0.92rem; margin-bottom: 0.5rem; }
.reveal-card .reveal-row { display: grid; grid-template-columns: 6rem 1fr 1fr; gap: 0.6rem; align-items: center; font-family: var(--mono); font-size: 0.95rem; padding: 0.25rem 0; }
.reveal-card .reveal-row .lbl { color: var(--text-secondary); font-family: inherit; font-size: 0.83rem; text-align: right; }
.reveal-card .reveal-row .user-ans { color: var(--error); }
.reveal-card .reveal-row .user-ans.ok { color: var(--ok); }
.reveal-card .reveal-row .correct-ans { color: var(--ok); font-weight: 600; }
.reveal-card .chord-label { color: var(--text-tertiary); font-size: 0.82rem; margin-top: 0.4rem; }
.reveal-card .next-row { display: flex; justify-content: flex-end; margin-top: 0.7rem; }

.correct-flash { animation: flash-ok 0.4s ease; }
.wrong-flash { animation: flash-err 0.4s ease; }
@keyframes flash-ok { 0% { background: var(--ok-soft); } 100% { background: var(--staff-bg); } }
@keyframes flash-err { 0% { background: var(--error-soft); } 100% { background: var(--staff-bg); } }

/* ===== RESULTS SCREEN ===== */
.results-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 0.8rem;
  margin-bottom: 1.4rem;
}
.metric-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1rem 1.2rem;
}
.metric-card .metric-value { font-size: 1.8rem; font-weight: 600; color: var(--accent); }
.metric-card .metric-label { font-size: 0.78rem; color: var(--text-secondary); text-transform: uppercase; letter-spacing: 0.04em; margin-top: 0.2rem; }

.missed-list { background: var(--bg-secondary); border: 1px solid var(--border); border-radius: var(--radius); overflow: hidden; }
.missed-row { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 0.6rem; padding: 0.6rem 1rem; border-top: 1px solid var(--border); font-size: 0.85rem; align-items: center; }
.missed-row:first-child { border-top: none; }
.missed-row .lbl { color: var(--text-secondary); font-size: 0.78rem; }
.missed-row .ans { font-family: var(--mono); }

/* ===== STATS DASHBOARD ===== */
.stats-section { margin-bottom: 1.5rem; }
.stats-section h3 { font-size: 1rem; margin-bottom: 0.6rem; }
.stats-table { width: 100%; border-collapse: collapse; font-size: 0.85rem; background: var(--bg-secondary); border: 1px solid var(--border); border-radius: var(--radius); overflow: hidden; }
.stats-table th, .stats-table td { padding: 0.55rem 0.85rem; text-align: left; border-bottom: 1px solid var(--border); }
.stats-table th { background: var(--bg-tertiary); font-weight: 600; font-size: 0.78rem; color: var(--text-secondary); text-transform: uppercase; letter-spacing: 0.03em; }
.stats-table tr:last-child td { border-bottom: none; }
.stats-table td.num { font-family: var(--mono); text-align: right; }

.keyheat-grid { display: grid; grid-template-columns: repeat(13, 1fr); gap: 4px; max-width: 600px; }
.keyheat-cell { aspect-ratio: 1; border-radius: 4px; display: flex; align-items: center; justify-content: center; font-size: 0.78rem; color: var(--text-primary); background: var(--bg-tertiary); }
.keyheat-cell.h0 { background: var(--bg-tertiary); color: var(--text-tertiary); }
.keyheat-cell.h1 { background: rgba(45, 164, 78, 0.25); }
.keyheat-cell.h2 { background: rgba(45, 164, 78, 0.5); color: white; }
.keyheat-cell.h3 { background: rgba(45, 164, 78, 0.85); color: white; }

.toolbar { display: flex; gap: 0.5rem; margin-bottom: 1rem; }

/* ===== ERRORS ===== */
.error-banner {
  background: var(--error-soft);
  color: var(--error);
  border: 1px solid var(--error);
  border-radius: 6px;
  padding: 0.5rem 0.9rem;
  font-size: 0.85rem;
  margin-bottom: 0.6rem;
}
.warn-banner {
  background: var(--accent-soft);
  color: var(--accent);
  border: 1px solid var(--accent);
  border-radius: 6px;
  padding: 0.5rem 0.9rem;
  font-size: 0.85rem;
  margin-bottom: 0.6rem;
}

/* ====================================================================
 * Triage home — category tiles
 * ==================================================================== */
.category-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 1rem;
  margin-top: 0.5rem;
}

.category-card {
  position: relative;
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.2rem 1.1rem 1.1rem;
  cursor: pointer;
  transition: border-color 0.12s ease, transform 0.06s ease, box-shadow 0.12s ease;
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
  min-height: 140px;
}
.category-card:hover:not(.disabled) {
  border-color: var(--accent);
  box-shadow: var(--shadow);
  transform: translateY(-1px);
}
.category-card:focus { outline: none; }
.category-card:focus-visible:not(.disabled) {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-soft);
}

.category-icon {
  font-size: 1.7rem;
  line-height: 1;
  color: var(--accent);
}
.category-label {
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--text-primary);
}
.category-blurb {
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.35;
}

.category-card.disabled {
  cursor: not-allowed;
  opacity: 0.55;
  background: var(--bg-tertiary);
}
.category-card.disabled:hover { border-color: var(--border); transform: none; box-shadow: none; }
.category-card.disabled .category-icon { color: var(--text-tertiary); }

.soon-badge {
  position: absolute;
  top: 0.6rem;
  right: 0.7rem;
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--text-tertiary);
  background: var(--bg-primary);
  border: 1px solid var(--border);
  padding: 0.15rem 0.45rem;
  border-radius: 999px;
}

.back-link {
  display: inline-block;
  font-size: 0.85rem;
  color: var(--text-secondary);
  text-decoration: none;
  margin-bottom: 0.6rem;
}
.back-link:hover { color: var(--accent); }

/* ====================================================================
 * Keys-drill UI
 * ==================================================================== */

/* The prompt under the stimulus (e.g. "___ Major", "G major — tap the sharps in order"). */
.keys-prompt {
  text-align: center;
  font-size: 1rem;
  color: var(--text-secondary);
  margin: 0.75rem 0;
}
.keys-t2-stimulus {
  font-size: 1.4rem;
  font-weight: 600;
  text-align: center;
  padding: 1.2rem 0.5rem;
  color: var(--text-primary);
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}

/* Letter keypad — visual peer of .kpad, but laid out for letters + modifiers. */
.lkpad {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0.85rem;
  width: 100%;
  max-width: 480px;
  margin: 0 auto;
}
.lkpad.disabled { opacity: 0.55; pointer-events: none; }
.lkpad-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  min-height: 1.1rem;
  margin-bottom: 0.45rem;
  font-size: 0.78rem;
}
.lkpad-len { color: var(--text-secondary); }
.lkpad-modbadge {
  color: var(--accent);
  font-weight: 600;
  padding: 0.05rem 0.4rem;
  border: 1px solid var(--accent);
  border-radius: 999px;
  font-size: 0.74rem;
}
.lkpad-display {
  min-height: 2.1rem;
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 0.4rem 0.55rem;
  background: var(--bg-primary);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.2rem;
  margin-bottom: 0.85rem;
}
.lkpad-chip {
  display: inline-block;
  background: var(--accent-soft);
  color: var(--accent);
  border-radius: 4px;
  padding: 0.1rem 0.45rem;
  font-family: var(--mono);
  font-size: 0.95rem;
}
.lkpad-dash { color: var(--text-tertiary); font-family: var(--mono); }
.lkpad-placeholder { color: var(--text-tertiary); font-style: italic; font-size: 0.85rem; }

.lkpad-letters {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  gap: 0.4rem;
  margin-bottom: 0.55rem;
}
.lkpad-controls {
  display: flex;
  gap: 0.4rem;
  align-items: center;
  flex-wrap: wrap;
}
.lkpad-sep { flex: 0 0 0.4rem; }

.lkpad-btn {
  background: var(--bg-primary);
  border: 1px solid var(--border);
  color: var(--text-primary);
  border-radius: 6px;
  padding: 0.55rem 0.5rem;
  font-size: 1.05rem;
  font-weight: 500;
  cursor: pointer;
  transition: background 0.06s ease, border-color 0.06s ease, transform 0.06s ease;
}
.lkpad-btn:hover { border-color: var(--accent); }
.lkpad-btn:active { transform: scale(0.97); background: var(--accent-soft); }
.lkpad-btn.lkpad-mod { color: var(--accent); font-size: 1.3rem; min-width: 46px; }
.lkpad-btn.lkpad-mod.active { background: var(--accent); color: white; border-color: var(--accent); }
.lkpad-btn.lkpad-bksp { font-size: 1.2rem; min-width: 56px; }
.lkpad-btn.lkpad-submit, .lkpad-btn.primary {
  background: var(--accent);
  color: white;
  border-color: var(--accent);
  font-weight: 600;
  margin-left: auto;
}
.lkpad-btn.lkpad-submit:hover, .lkpad-btn.primary:hover { background: var(--accent-strong); }

.lkpad-hint {
  margin-top: 0.55rem;
  font-size: 0.74rem;
  color: var(--text-tertiary);
  text-align: center;
}

/* ====================================================================
 * Intervals-drill UI
 * ==================================================================== */

/* Pill shown above the staff in Tier 2 (Complete): e.g. "M2 ↑". */
.interval-chip {
  display: block;
  width: fit-content;
  margin: 0.4rem auto 0.7rem;
  background: var(--accent-soft);
  color: var(--accent);
  border: 1px solid var(--accent);
  padding: 0.3rem 1rem;
  border-radius: 999px;
  font-size: 1.15rem;
  font-weight: 600;
  font-family: var(--mono);
  letter-spacing: 0.05em;
}

/* 11-button interval-name keypad. */
.ikpad {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0.85rem;
  width: 100%;
  max-width: 480px;
  margin: 0 auto;
}
.ikpad.disabled { opacity: 0.55; pointer-events: none; }
.ikpad-top {
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 1.4rem;
  margin-bottom: 0.55rem;
  font-size: 0.85rem;
}
.ikpad-selected {
  color: var(--text-secondary);
  font-family: var(--mono);
  text-align: center;
}
.ikpad-row {
  display: flex;
  gap: 0.45rem;
  justify-content: center;
  margin-bottom: 0.45rem;
}
.ikpad-btn {
  background: var(--bg-primary);
  border: 1px solid var(--border);
  color: var(--text-primary);
  border-radius: 6px;
  padding: 0.6rem 0.8rem;
  font-size: 1rem;
  font-weight: 500;
  cursor: pointer;
  min-width: 70px;
  transition: background 0.06s ease, border-color 0.06s ease, transform 0.06s ease;
}
.ikpad-btn:hover { border-color: var(--accent); }
.ikpad-btn:active { transform: scale(0.97); background: var(--accent-soft); }
.ikpad-btn.selected {
  background: var(--accent);
  color: white;
  border-color: var(--accent);
}
.ikpad-controls {
  display: flex;
  gap: 0.4rem;
  justify-content: center;
  align-items: center;
  margin-top: 0.55rem;
}
.ikpad-btn.ikpad-bksp { font-size: 1.2rem; min-width: 56px; }
.ikpad-btn.ikpad-submit, .ikpad-btn.primary {
  background: var(--accent);
  color: white;
  border-color: var(--accent);
  font-weight: 600;
  min-width: 110px;
}
.ikpad-btn.ikpad-submit:hover, .ikpad-btn.primary:hover { background: var(--accent-strong); }
.ikpad-hint {
  margin-top: 0.55rem;
  font-size: 0.74rem;
  color: var(--text-tertiary);
  text-align: center;
}