:root {
  color-scheme: dark;
  --ear-bg: #101318;
  --ear-panel: #171d25;
  --ear-panel-soft: #1d2530;
  --ear-border: rgba(255, 255, 255, 0.14);
  --ear-accent: #88bc55;
  --ear-accent-2: #e1b84f;
  --ear-danger: #dc6b58;
  --ear-info: #57b7c5;
}

body {
  min-height: 100vh;
  background:
    radial-gradient(circle at 12% 0%, rgba(136, 188, 85, 0.18), transparent 24rem),
    linear-gradient(145deg, #101318, #161c24 55%, #101318);
}

.ear-nav {
  min-height: 4.25rem;
  border-bottom: 1px solid var(--ear-border);
  background: rgba(16, 19, 24, 0.78);
  backdrop-filter: blur(0.75rem);
}

.brand-mark {
  width: 2rem;
  height: 2rem;
  border-radius: 0.4rem;
}

.ear-shell {
  width: min(100%, 74rem);
  margin: 0 auto;
  padding: 1rem;
}

.ear-heading {
  display: grid;
  gap: 0.45rem;
  margin: 0.75rem 0 1.1rem;
}

.ear-heading h1 {
  margin: 0;
  font-size: clamp(1.7rem, 8vw, 3.2rem);
  line-height: 1;
}

.ear-heading p {
  max-width: 42rem;
  margin: 0;
  color: var(--bs-secondary-color);
}

.lesson-hint-list {
  display: grid;
  gap: 0.45rem;
  max-width: 46rem;
  margin: 0.25rem 0 0;
  padding-left: 1.25rem;
  color: var(--bs-body-color);
}

.module-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0.85rem;
}

.module-card,
.lesson-board,
.teaching-panel,
.trainer-panel,
.summary-panel {
  border: 1px solid var(--ear-border);
  border-radius: 0.5rem;
  background: rgba(23, 29, 37, 0.92);
  box-shadow: 0 0.8rem 2rem rgba(0, 0, 0, 0.22);
}

.module-card {
  display: grid;
  min-height: 10rem;
  padding: 1rem;
  color: #fff;
  text-decoration: none;
  transition: border-color 160ms ease, transform 160ms ease;
}

.module-card:hover,
.module-card:focus-visible {
  border-color: color-mix(in srgb, var(--ear-accent), white 42%);
  color: #fff;
  transform: translateY(-0.12rem);
}

.module-card.is-locked {
  opacity: 0.72;
}

.module-title-row,
.metric-row,
.trainer-topline,
.answer-result {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
}

.module-title {
  margin: 0;
  font-size: 1.05rem;
  line-height: 1.15;
}

.module-description {
  margin: 0.35rem 0 0;
  color: var(--bs-secondary-color);
  font-size: 0.92rem;
}

.score-pill {
  min-width: 4.4rem;
  padding: 0.35rem 0.5rem;
  border: 1px solid rgba(255, 255, 255, 0.16);
  border-radius: 999rem;
  background: rgba(255, 255, 255, 0.06);
  text-align: center;
  font-weight: 800;
}

.stars {
  color: var(--ear-accent-2);
  letter-spacing: 0.08rem;
  white-space: nowrap;
}

.lesson-board {
  padding: 1rem;
}

.teaching-panel {
  display: grid;
  gap: 1rem;
  padding: 1rem;
}

.teaching-panel h2,
.teaching-panel h3,
.teaching-panel p {
  margin: 0;
}

.teaching-copy {
  display: grid;
  gap: 0.72rem;
  color: var(--bs-secondary-color);
}

.teaching-copy strong {
  color: var(--bs-body-color);
}

.teaching-copy h2,
.teaching-copy h3 {
  color: var(--bs-body-color);
}

.teaching-copy hr {
  width: 100%;
  margin: 0.35rem 0;
  border-color: rgba(255, 255, 255, 0.18);
  opacity: 1;
}

.teaching-copy ul,
.teaching-copy ol {
  margin: 0;
  padding-left: 1.25rem;
}

.interval-formula {
  width: fit-content;
  padding: 0.45rem 0.65rem;
  border: 1px solid rgba(225, 184, 79, 0.42);
  border-radius: 0.4rem;
  color: #fff3c4;
  background: rgba(225, 184, 79, 0.12);
  font-weight: 900;
  text-align: left;
  cursor: pointer;
}

.interval-formula:hover,
.interval-formula:focus-visible {
  border-color: rgba(225, 184, 79, 0.86);
  color: #fff8dc;
  background: rgba(225, 184, 79, 0.2);
  box-shadow: 0 0 0 0.16rem rgba(225, 184, 79, 0.18);
}

.teaching-table {
  margin: 0;
  --bs-table-bg: rgba(255, 255, 255, 0.035);
  --bs-table-border-color: rgba(255, 255, 255, 0.14);
}

.teaching-actions,
.teaching-demo-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.55rem;
}

.teaching-demo {
  display: grid;
  gap: 0.9rem;
  padding: 1rem;
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: 0.45rem;
  background: rgba(255, 255, 255, 0.045);
}

.lesson-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.65rem;
}

.lesson-button {
  min-height: 4.4rem;
  display: grid;
  align-content: center;
  gap: 0.15rem;
  text-align: left;
}

.lesson-button.is-complete {
  border-color: rgba(136, 188, 85, 0.8);
  background: rgba(136, 188, 85, 0.16);
}

.lesson-button.is-next {
  border-color: rgba(87, 183, 197, 0.9);
  box-shadow: 0 0 0 0.16rem rgba(87, 183, 197, 0.24);
  font-weight: 800;
}

.lesson-button span {
  display: block;
}

.lesson-score {
  color: var(--bs-secondary-color);
  font-size: 0.84rem;
}

.lesson-hint {
  color: var(--bs-secondary-color);
  font-size: 0.78rem;
}

.lesson-stars {
  color: #f2c94c;
  letter-spacing: 0.06rem;
}

.lesson-explanation-list {
  display: grid;
  gap: 0.65rem;
}

.lesson-explanation {
  display: block;
  padding: 0.8rem;
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: 0.45rem;
  color: var(--bs-body-color);
  text-decoration: none;
  background: rgba(255, 255, 255, 0.045);
  transition: border-color 160ms ease, transform 160ms ease, background 160ms ease;
}

.lesson-explanation:hover,
.lesson-explanation:focus-visible {
  border-color: rgba(87, 183, 197, 0.74);
  color: var(--bs-body-color);
  background: rgba(87, 183, 197, 0.08);
  transform: translateY(-0.08rem);
}

.lesson-explanation.is-complete {
  border-color: rgba(136, 188, 85, 0.68);
  background: rgba(136, 188, 85, 0.1);
}

.lesson-explanation-topline {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 0.75rem;
  margin-bottom: 0.35rem;
}

.lesson-explanation h3,
.lesson-explanation p {
  margin: 0;
}

.lesson-explanation h3 {
  font-size: 1rem;
}

.lesson-explanation p + p {
  margin-top: 0.3rem;
  color: var(--bs-secondary-color);
}

.module-stat-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.55rem;
}

.module-stat-grid div {
  display: grid;
  gap: 0.15rem;
  padding: 0.65rem;
  border-radius: 0.45rem;
  background: rgba(255, 255, 255, 0.055);
}

.module-stat-grid strong {
  font-size: 1.15rem;
  line-height: 1;
}

.module-stat-grid span {
  color: var(--bs-secondary-color);
  font-size: 0.82rem;
}

.trainer-layout {
  display: grid;
  gap: 1rem;
}

.trainer-panel,
.summary-panel {
  padding: 1rem;
}

#startButton {
  margin-left: auto;
}

.trainer-progress {
  height: 0.55rem;
  overflow: hidden;
  border-radius: 999rem;
  background: rgba(255, 255, 255, 0.09);
}

.trainer-progress-bar {
  width: 0%;
  height: 100%;
  border-radius: inherit;
  background: linear-gradient(90deg, var(--ear-accent), var(--ear-info));
  transition: width 180ms ease;
}

.answer-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.55rem;
}

.answer-grid .btn {
  position: relative;
  overflow: visible;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.65rem;
  min-height: 3.1rem;
  text-align: left;
}

.answer-key-hint {
  flex: 0 0 auto;
  min-width: 1.45rem;
  min-height: 1.45rem;
  display: inline-grid;
  place-items: center;
  border: 1px solid rgba(255, 255, 255, 0.24);
  border-radius: 0.35rem;
  color: #f7f9fb;
  background: rgba(255, 255, 255, 0.12);
  font-size: 0.78rem;
  font-weight: 900;
  line-height: 1;
}

.answer-grid .btn:hover .answer-key-hint,
.answer-grid .btn:focus-visible .answer-key-hint {
  border-color: rgba(0, 0, 0, 0.34);
  color: #12161c;
  background: rgba(255, 255, 255, 0.84);
}

.answer-grid .btn.is-selected {
  border-color: var(--ear-info);
  box-shadow: 0 0 0 0.16rem rgba(87, 183, 197, 0.28);
}

.answer-grid .btn.is-correct {
  border-color: var(--ear-accent);
  background: rgba(136, 188, 85, 0.18);
}

.answer-grid .btn.is-wrong {
  border-color: var(--ear-danger);
  background: rgba(220, 107, 88, 0.14);
}

.answer-confetti {
  position: absolute;
  left: 50%;
  top: 48%;
  z-index: 4;
  pointer-events: none;
}

.answer-confetti span {
  position: absolute;
  width: 0.58rem;
  height: 0.58rem;
  border-radius: 50%;
  background: hsl(var(--hue), 88%, 62%);
  box-shadow: 0 0 0.45rem hsl(var(--hue), 88%, 62%);
  animation: answer-confetti-pop 820ms ease-out forwards;
}

@keyframes answer-confetti-pop {
  0% {
    opacity: 1;
    transform: translate(-50%, -50%) scale(0.4);
  }

  100% {
    opacity: 0;
    transform: translate(calc(-50% + var(--x)), calc(-50% + var(--y))) scale(1.45);
  }
}

.loop-replay-control {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  min-height: 3rem;
  padding: 0 0.55rem;
  border: 1px solid rgba(255, 255, 255, 0.16);
  border-radius: 0.45rem;
  color: var(--bs-body-color);
  background: rgba(255, 255, 255, 0.055);
  font-weight: 700;
}

.shortcut-help {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  margin-top: 0.55rem;
  color: var(--bs-secondary-color);
  font-size: 0.84rem;
}

.shortcut-help span {
  padding: 0.32rem 0.45rem;
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: 0.35rem;
  background: rgba(255, 255, 255, 0.045);
}

.shortcut-help kbd {
  padding: 0.08rem 0.28rem;
  border: 1px solid rgba(255, 255, 255, 0.22);
  border-radius: 0.25rem;
  color: #f9fbfd;
  background: rgba(0, 0, 0, 0.36);
  font-size: 0.76rem;
}

.trainer-summary {
  grid-column: 1 / -1;
  display: grid;
  gap: 0.9rem;
  padding: 1rem;
  border: 1px solid rgba(255, 255, 255, 0.14);
  border-radius: 0.5rem;
  background: rgba(255, 255, 255, 0.055);
}

.trainer-summary h3,
.trainer-summary p {
  margin: 0;
}

.summary-metrics,
.summary-actions {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0.55rem;
}

.summary-metrics span {
  padding: 0.65rem;
  border-radius: 0.4rem;
  background: rgba(0, 0, 0, 0.18);
}

.ear-piano {
  position: relative;
  width: 100%;
  max-width: 46rem;
  aspect-ratio: 14 / 3.4;
  margin: 0 auto;
  touch-action: manipulation;
}

.piano-whites {
  display: grid;
  grid-template-columns: repeat(14, minmax(0, 1fr));
  height: 100%;
}

.piano-key {
  position: relative;
  border: 1px solid #29313b;
  color: #12161c;
  font-weight: 800;
  line-height: 1;
}

.piano-key.white {
  display: flex;
  align-items: flex-end;
  justify-content: center;
  padding: 0 0.1rem 0.45rem;
  border-radius: 0 0 0.28rem 0.28rem;
  background: linear-gradient(#f8f7ee, #d7d5c9);
  font-size: clamp(0.62rem, 2.4vw, 0.84rem);
}

.piano-key.black {
  position: absolute;
  top: 0;
  z-index: 3;
  width: 5.25%;
  height: 61%;
  padding: 0 0.05rem 0.35rem;
  border-color: #06080a;
  border-radius: 0 0 0.24rem 0.24rem;
  background: linear-gradient(#252b32, #050607);
  color: #f3f5f7;
  font-size: clamp(0.52rem, 1.9vw, 0.72rem);
}

.piano-key.is-highlighted {
  border-color: #ffe27a;
  outline: 0.28rem solid #ffe27a;
  outline-offset: -0.34rem;
  box-shadow:
    inset 0 0 0 999rem rgba(255, 226, 122, 0.34),
    0 0 1.15rem rgba(255, 226, 122, 0.86);
  transform: translateY(-0.16rem);
}

.piano-key.is-root {
  border-color: #61d9ff;
  outline-color: #61d9ff;
  box-shadow:
    inset 0 0 0 999rem rgba(97, 217, 255, 0.34),
    0 0 1.15rem rgba(97, 217, 255, 0.84);
}

.piano-key:focus-visible {
  outline: 0.2rem solid var(--ear-accent);
  outline-offset: -0.2rem;
}

.piano-key.is-flashing {
  animation: piano-key-flash 220ms ease-out;
}

@keyframes piano-key-flash {
  0% {
    filter: brightness(1);
    box-shadow: 0 0 0 rgba(255, 255, 255, 0);
  }

  50% {
    filter: brightness(1.38);
    box-shadow: 0 0 1rem rgba(255, 255, 255, 0.8);
  }

  100% {
    filter: brightness(1);
    box-shadow: 0 0 0 rgba(255, 255, 255, 0);
  }
}

.weak-list {
  display: grid;
  gap: 0.45rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.weak-list li {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  padding: 0.55rem 0.65rem;
  border-radius: 0.4rem;
  background: rgba(255, 255, 255, 0.055);
}

.weak-skill-main {
  min-width: 0;
  flex: 1 1 auto;
  display: grid;
  gap: 0.32rem;
}

.weak-skill-main > span {
  overflow-wrap: anywhere;
}

.weak-skill-meter {
  height: 0.38rem;
  overflow: hidden;
  border-radius: 999rem;
  background: rgba(220, 107, 88, 0.34);
}

.weak-skill-meter span {
  display: block;
  height: 100%;
  min-width: 0.25rem;
  border-radius: inherit;
  background: linear-gradient(90deg, var(--ear-danger), var(--ear-accent-2) 42%, var(--ear-accent));
}

.skill-result-counts {
  flex: 0 0 auto;
  display: inline-flex;
  align-items: center;
  gap: 0.28rem;
  font-weight: 900;
}

.skill-result-counts span {
  min-width: 1.45rem;
  min-height: 1.45rem;
  display: inline-grid;
  place-items: center;
  border-radius: 999rem;
}

.skill-result-counts .is-good {
  color: #eaffdd;
  background: rgba(136, 188, 85, 0.24);
}

.skill-result-counts .is-bad {
  color: #ffe4df;
  background: rgba(220, 107, 88, 0.24);
}

.status-line {
  min-height: 1.5rem;
  color: var(--bs-secondary-color);
}

@media (min-width: 560px) {
  .module-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .lesson-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .summary-metrics,
  .summary-actions {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .summary-actions {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 900px) {
  .module-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .trainer-layout {
    grid-template-columns: minmax(0, 1fr) 18rem;
    align-items: start;
  }
}