/* Тренажёр сложения и вычитания дробей. tokens-only. Все селекторы под .app--fraction-add-subtract. */
.app--fraction-add-subtract {
  position: relative;
  max-width: 72rem;
  margin: 0 auto;
  padding: var(--space-2) var(--space-4) var(--space-8);
  font-family: var(--font-body);
  color: var(--text);
}

.app--fraction-add-subtract [hidden] {
  display: none !important;
}

.app--fraction-add-subtract .fas-sr {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

.app--fraction-add-subtract .fas-confetti,
.app--fraction-add-subtract .trainer-quiz-confetti {
  pointer-events: none;
  position: absolute;
  inset: 0;
  overflow: hidden;
  z-index: 40;
}

.app--fraction-add-subtract .fas-confetti .cp,
.app--fraction-add-subtract .trainer-quiz-confetti .cp {
  position: absolute;
  top: -12px;
  border-radius: 2px;
  animation-name: fas-confetti-fall;
  animation-timing-function: ease-in;
  animation-fill-mode: forwards;
}

@keyframes fas-confetti-fall {
  to {
    transform: translateY(110vh) rotate(480deg);
    opacity: 0;
  }
}

.app--fraction-add-subtract .fas-exit {
  margin-bottom: var(--space-2);
}

.app--fraction-add-subtract .fas-back {
  min-height: 44px;
  padding: 0 var(--space-3);
  border-radius: var(--radius-full);
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--primary);
  font: inherit;
  font-size: var(--text-sm);
  font-weight: 700;
  cursor: pointer;
  touch-action: manipulation;
}

.app--fraction-add-subtract .fas-workspace {
  padding: var(--space-4);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  background: var(--surface);
  box-shadow: var(--shadow-sm);
  box-sizing: border-box;
}

.app--fraction-add-subtract .fas-topbar {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  margin-bottom: var(--space-4);
}

.app--fraction-add-subtract .fas-tabs {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--space-2);
}

.app--fraction-add-subtract .fas-tab {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  min-width: 0;
  min-height: 56px;
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
  background: var(--surface-2);
  font: inherit;
  text-align: left;
  cursor: pointer;
  touch-action: manipulation;
  transition:
    background 130ms ease,
    border-color 130ms ease,
    color 130ms ease,
    transform 130ms ease;
}

.app--fraction-add-subtract .fas-tab:disabled {
  cursor: not-allowed;
  opacity: 0.72;
}

.app--fraction-add-subtract .fas-tab__icon {
  flex-shrink: 0;
  font-size: var(--text-lg);
  line-height: 1;
}

.app--fraction-add-subtract .fas-tab__text {
  display: flex;
  flex-direction: column;
  min-width: 0;
}

.app--fraction-add-subtract .fas-tab__title {
  font-family: var(--font-display);
  font-size: clamp(0.875rem, 3.2vw, 1rem);
  font-weight: 800;
  line-height: 1.2;
}

.app--fraction-add-subtract .fas-tab__sub {
  display: block;
  font-size: clamp(0.625rem, 2.4vw, 0.75rem);
  font-weight: 600;
  line-height: 1.25;
  color: var(--text-muted);
}

.app--fraction-add-subtract .fas-tab.is-active {
  background: var(--primary);
  color: var(--text-inv);
  border-color: var(--primary);
  box-shadow: var(--shadow-sm);
}

.app--fraction-add-subtract .fas-tab.is-active .fas-tab__sub {
  color: color-mix(in srgb, var(--text-inv) 85%, transparent);
}

.app--fraction-add-subtract .fas-tab:active:not(:disabled) {
  transform: scale(0.98);
}

.app--fraction-add-subtract .fas-config,
.app--fraction-add-subtract .fas-solve,
.app--fraction-add-subtract .fas-summary {
  margin-block: var(--space-4) var(--space-6);
}

.app--fraction-add-subtract .fas-config {
  width: 100%;
  max-width: 36rem;
  margin-inline: auto;
}

.app--fraction-add-subtract .fas-config-head {
  margin-bottom: var(--space-4);
  text-align: center;
}

.app--fraction-add-subtract .fas-config-title {
  margin: 0 0 var(--space-2);
  font-family: var(--font-display);
  font-size: clamp(1.2rem, 4vw, 1.5rem);
  font-weight: 800;
  line-height: 1.2;
}

.app--fraction-add-subtract .fas-config-lead {
  margin: 0;
  font-size: 1rem;
  line-height: 1.45;
  color: var(--text-muted);
}

.app--fraction-add-subtract .fas-kinds {
  display: grid;
  gap: var(--space-3);
  grid-template-columns: 1fr;
}

.app--fraction-add-subtract .fas-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.35rem;
  min-height: 88px;
  text-align: center;
  padding: var(--space-4) var(--space-3);
  border-radius: var(--radius-lg);
  border: 2px solid var(--border);
  background: var(--surface-2);
  box-shadow: var(--trainer-shadow-card, var(--shadow-md));
  font: inherit;
  cursor: pointer;
  touch-action: manipulation;
}

.app--fraction-add-subtract .fas-card.is-active {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px var(--primary-bg);
}

.app--fraction-add-subtract .fas-card-title {
  font-weight: 800;
}

.app--fraction-add-subtract .fas-card-hint {
  color: var(--text-muted);
  font-size: var(--text-sm);
  line-height: 1.35;
  max-width: 18rem;
}

.app--fraction-add-subtract .fas-card-example {
  margin-top: 0.15rem;
  font-family: var(--font-display);
  font-size: var(--text-lg);
  font-weight: 800;
  font-variant-numeric: tabular-nums;
  color: var(--primary);
}

.app--fraction-add-subtract .fas-start,
.app--fraction-add-subtract .fas-check,
.app--fraction-add-subtract .fas-next,
.app--fraction-add-subtract .fas-skip,
.app--fraction-add-subtract .fas-hint-btn {
  min-height: 44px;
  min-width: 44px;
  border-radius: var(--radius-lg);
  font: inherit;
  font-weight: 700;
  cursor: pointer;
  touch-action: manipulation;
}

.app--fraction-add-subtract .fas-start,
.app--fraction-add-subtract .fas-check,
.app--fraction-add-subtract .fas-next {
  border: 0;
  background: var(--primary);
  color: var(--text-inv);
  padding: 0.7rem 1.4rem;
}

.app--fraction-add-subtract .fas-start {
  width: 100%;
  min-height: 56px;
  margin-top: var(--space-4);
  background: var(--primary);
  font-size: 1.125rem;
  font-weight: 800;
}

.app--fraction-add-subtract .fas-skip,
.app--fraction-add-subtract .fas-hint-btn {
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text);
  padding: 0.45rem 0.9rem;
  box-shadow: var(--shadow-sm);
}

.app--fraction-add-subtract .fas-solve-head {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
  margin-bottom: var(--space-3);
}

.app--fraction-add-subtract .fas-badge {
  display: inline-block;
  padding: 0.2em 0.55em;
  border-radius: var(--radius-md);
  background: var(--primary-bg);
  color: var(--primary);
  font-weight: 800;
  font-size: var(--text-sm);
}

.app--fraction-add-subtract .fas-progress-text {
  font-size: var(--text-sm);
  font-weight: 800;
  color: var(--text-muted);
}

.app--fraction-add-subtract .fas-progress {
  height: 8px;
  margin-bottom: var(--space-4);
  overflow: hidden;
  border-radius: var(--radius-full);
  background: var(--border);
}

.app--fraction-add-subtract .fas-progress__fill {
  display: block;
  width: 0;
  height: 100%;
  border-radius: inherit;
  background: var(--primary);
  transition: width 240ms ease;
}

.app--fraction-add-subtract .fas-solve-layout {
  display: flex;
  flex-direction: column;
  gap: 0;
  min-height: 0;
}

.app--fraction-add-subtract .fas-solve-main {
  flex: 1;
  min-height: 0;
}

.app--fraction-add-subtract .fas-work {
  padding: var(--space-4);
  border: 1px dashed var(--border);
  border-radius: var(--radius-lg);
  background: var(--surface-2);
}

.app--fraction-add-subtract .fas-expression {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: clamp(0.5rem, 2.2vw, 1.25rem);
  max-width: 100%;
  font-size: clamp(2.35rem, 5vw, 3.5rem);
  font-weight: 800;
  line-height: 1;
  margin: var(--space-4) 0 var(--space-6);
}

.app--fraction-add-subtract .fas-fraction {
  display: inline-grid;
  grid-template-rows: 1fr 1fr;
  min-width: 1.4em;
  text-align: center;
  vertical-align: middle;
}

.app--fraction-add-subtract .fas-fraction__num {
  padding: 0 0.15em 0.12em;
  border-bottom: 3px solid currentColor;
}

.app--fraction-add-subtract .fas-fraction__den {
  padding: 0.12em 0.15em 0;
}

.app--fraction-add-subtract .fas-op,
.app--fraction-add-subtract .fas-equals {
  font-size: 0.85em;
  font-weight: 700;
}

.app--fraction-add-subtract .fas-answer {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 1.45em;
}

.app--fraction-add-subtract .fas-input {
  display: inline-grid;
  justify-items: center;
  gap: 0.12rem;
  padding: 3px;
  border-radius: var(--radius-lg);
}

.app--fraction-add-subtract .fas-input__num,
.app--fraction-add-subtract .fas-input__den {
  width: 4.5rem;
  height: 3.15rem;
  box-sizing: border-box;
  text-align: center;
  font-size: 1.8rem;
  font-weight: 800;
  font-family: inherit;
  border: 2px solid var(--border);
  border-radius: var(--radius-md);
  background: var(--surface);
  color: var(--text);
  font-variant-numeric: tabular-nums;
  caret-color: var(--primary);
}

.app--fraction-add-subtract .fas-input__num:focus,
.app--fraction-add-subtract .fas-input__den:focus,
.app--fraction-add-subtract .fas-input__num.is-active,
.app--fraction-add-subtract .fas-input__den.is-active {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px var(--primary-bg);
}

.app--fraction-add-subtract .fas-input__num:disabled,
.app--fraction-add-subtract .fas-input__den:disabled {
  opacity: 1;
  color: var(--text);
  -webkit-text-fill-color: var(--text);
}

.app--fraction-add-subtract .fas-input__num.is-ok,
.app--fraction-add-subtract .fas-input__den.is-ok {
  border-color: var(--success);
  background: var(--success-bg);
}

.app--fraction-add-subtract .fas-input__num.is-bad,
.app--fraction-add-subtract .fas-input__den.is-bad {
  border-color: var(--error);
  background: var(--error-bg);
}

.app--fraction-add-subtract .fas-input__num.is-warn,
.app--fraction-add-subtract .fas-input__den.is-warn {
  border-color: var(--warning, #c47d12);
  background: color-mix(in srgb, var(--warning, #c47d12) 12%, var(--surface));
}

.app--fraction-add-subtract .fas-input__line {
  width: 4.5rem;
  height: 3px;
  background: currentColor;
  border-radius: 2px;
}

.app--fraction-add-subtract .fas-input.is-ok {
  background: var(--success-bg);
}

.app--fraction-add-subtract .fas-input.is-bad {
  background: var(--error-bg);
}

.app--fraction-add-subtract .fas-input.is-warn {
  background: color-mix(in srgb, var(--warning, #c47d12) 12%, var(--surface));
}

.app--fraction-add-subtract .fas-input.is-revealed {
  background: var(--primary-bg);
}

.app--fraction-add-subtract .fas-input.is-ok .fas-input__num,
.app--fraction-add-subtract .fas-input.is-ok .fas-input__den {
  border-color: var(--success);
}

.app--fraction-add-subtract .fas-input.is-bad .fas-input__num,
.app--fraction-add-subtract .fas-input.is-bad .fas-input__den {
  border-color: var(--error);
}

.app--fraction-add-subtract .fas-input.is-warn .fas-input__num,
.app--fraction-add-subtract .fas-input.is-warn .fas-input__den {
  border-color: var(--warning, #c47d12);
}

.app--fraction-add-subtract .fas-input.is-revealed .fas-input__num,
.app--fraction-add-subtract .fas-input.is-revealed .fas-input__den {
  border-color: var(--primary);
}

.app--fraction-add-subtract .fas-feedback {
  min-height: 1.5rem;
  margin: var(--space-3) 0 0;
  text-align: center;
  font-weight: 700;
}

.app--fraction-add-subtract .fas-feedback.is-empty {
  color: transparent;
}

.app--fraction-add-subtract .fas-feedback.is-ok {
  color: var(--success);
}

.app--fraction-add-subtract .fas-feedback.is-bad {
  color: var(--error);
}

.app--fraction-add-subtract .fas-feedback.is-warn {
  color: var(--warning, #9a5b00);
}

.app--fraction-add-subtract .fas-check-notice {
  margin: var(--space-2) 0 0;
  text-align: center;
  font-size: var(--text-sm);
  color: var(--text-muted);
}

.app--fraction-add-subtract .fas-solve-dock {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  flex-shrink: 0;
  border-top: 1px solid var(--border);
  background: var(--surface);
  padding: 0.5rem 0 max(0.5rem, env(safe-area-inset-bottom, 0px));
  margin-top: var(--space-4);
}

.app--fraction-add-subtract .fas-back:focus-visible,
.app--fraction-add-subtract .fas-tab:focus-visible,
.app--fraction-add-subtract .fas-card:focus-visible,
.app--fraction-add-subtract .fas-start:focus-visible,
.app--fraction-add-subtract .fas-check:focus-visible,
.app--fraction-add-subtract .fas-next:focus-visible,
.app--fraction-add-subtract .fas-skip:focus-visible,
.app--fraction-add-subtract .fas-hint-btn:focus-visible,
.app--fraction-add-subtract .fas-key:focus-visible {
  outline: 3px solid var(--primary);
  outline-offset: 2px;
}

.app--fraction-add-subtract .fas-hint-card {
  margin-top: var(--space-2);
  padding: var(--space-3);
  border-radius: var(--radius-lg);
  background: var(--primary-bg);
  border: 1px solid var(--border);
}

.app--fraction-add-subtract .fas-hint-text,
.app--fraction-add-subtract .fas-scheme__line {
  margin: 0;
  font-size: var(--text-sm);
  line-height: 1.45;
}

.app--fraction-add-subtract .fas-scheme {
  margin-top: var(--space-2);
  font-weight: 700;
}

.app--fraction-add-subtract .fas-actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}

.app--fraction-add-subtract .fas-actions .fas-check,
.app--fraction-add-subtract .fas-actions .fas-skip {
  flex: 1 1 8rem;
}

.app--fraction-add-subtract .fas-numpad {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 6px;
  width: 100%;
}

.app--fraction-add-subtract .fas-key {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 52px;
  min-width: 44px;
  min-height: 48px;
  border: 1px solid color-mix(in srgb, var(--primary) 12%, var(--border));
  border-radius: 12px;
  background: var(--surface);
  box-shadow: 0 2px 6px color-mix(in srgb, var(--text) 7%, transparent);
  color: color-mix(in srgb, var(--primary) 72%, var(--text));
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 900;
  font-variant-numeric: tabular-nums;
  cursor: pointer;
  touch-action: manipulation;
  transition:
    transform 130ms ease,
    background 130ms ease,
    border-color 130ms ease,
    box-shadow 130ms ease;
}

.app--fraction-add-subtract .fas-key:active {
  transform: scale(0.95);
  box-shadow: none;
}

.app--fraction-add-subtract .fas-key--del {
  flex-direction: column;
  gap: 0;
  color: var(--text-muted);
  font-size: 0.72rem;
  font-weight: 700;
}

.app--fraction-add-subtract .fas-key-del__icon {
  font-size: 1.15rem;
  line-height: 1;
}

.app--fraction-add-subtract .fas-key-del__label {
  font-size: 0.62rem;
  line-height: 1;
}

.app--fraction-add-subtract .fas-key--ok {
  border-color: var(--success);
  background: var(--success);
  color: var(--text-inv);
}

.app--fraction-add-subtract .fas-success,
.app--fraction-add-subtract .fas-reveal,
.app--fraction-add-subtract .fas-summary {
  text-align: center;
  padding: var(--space-4);
}

.app--fraction-add-subtract .fas-success {
  margin-top: var(--space-3);
  background: var(--success-bg);
  border-radius: var(--radius-lg);
}

.app--fraction-add-subtract .fas-success__icon {
  margin: 0;
  font-size: 1.75rem;
  color: var(--success);
}

.app--fraction-add-subtract .fas-success__title,
.app--fraction-add-subtract .fas-summary__title {
  margin: var(--space-1) 0 var(--space-3);
  font-family: var(--font-display);
}

.app--fraction-add-subtract .fas-success__chain,
.app--fraction-add-subtract .fas-reveal__chain {
  margin: 0 0 var(--space-4);
  font-weight: 700;
}

.app--fraction-add-subtract .fas-reveal {
  margin-top: var(--space-3);
  background: var(--primary-bg);
  border-radius: var(--radius-lg);
}

.app--fraction-add-subtract .fas-reveal__label {
  margin: 0 0 var(--space-2);
  font-size: var(--text-sm);
  font-weight: 800;
  color: var(--text-muted);
}

.app--fraction-add-subtract .fas-reveal__text {
  margin: 0 0 var(--space-2);
  font-weight: 700;
}

.app--fraction-add-subtract .fas-summary__score {
  font-size: var(--text-xl);
  font-weight: 800;
  margin: 0 0 var(--space-4);
}

.app--fraction-add-subtract .fas-summary__stats {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--space-6);
  margin: 0 0 var(--space-6);
}

.app--fraction-add-subtract .fas-summary__stats dt {
  font-size: var(--text-sm);
  color: var(--text-muted);
}

.app--fraction-add-subtract .fas-summary__stats dd {
  margin: 0;
  font-size: var(--text-xl);
  font-weight: 800;
}

.app--fraction-add-subtract .fas-summary__actions {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--space-2);
}

.app--fraction-add-subtract .fas-overlay {
  position: fixed;
  inset: 0;
  z-index: 50;
  display: grid;
  place-items: center;
  background: rgba(30, 41, 59, 0.35);
  padding: var(--space-4);
}

.app--fraction-add-subtract .fas-dialog {
  width: min(100%, 22rem);
  background: var(--surface);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  box-shadow: var(--shadow-lg);
}

.app--fraction-add-subtract .fas-dialog-title {
  margin: 0 0 var(--space-2);
  font-size: var(--text-lg);
}

.app--fraction-add-subtract .fas-dialog-text {
  margin: 0 0 var(--space-4);
  color: var(--text-muted);
}

.app--fraction-add-subtract .fas-dialog-actions {
  display: flex;
  justify-content: flex-end;
  gap: var(--space-2);
}

@media (min-width: 640px) {
  .app--fraction-add-subtract .fas-kinds {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (min-width: 720px) {
  .app--fraction-add-subtract .fas-workspace {
    max-width: 48rem;
    margin-inline: auto;
  }

  .app--fraction-add-subtract .fas-tabs {
    max-width: 32rem;
  }

  .app--fraction-add-subtract .fas-solve-layout {
    display: grid;
    grid-template-columns: minmax(0, 1fr) 220px;
    align-items: start;
    gap: 0.75rem;
  }

  .app--fraction-add-subtract .fas-solve-dock {
    position: sticky;
    top: 4.5rem;
    bottom: auto;
    border-top: 0;
    border-left: 1px solid var(--border);
    margin-top: 0;
    padding: 0 0 0 0.75rem;
    box-shadow: none;
    align-self: start;
  }
}

@media (max-width: 719px) {
  .app--fraction-add-subtract {
    width: 100%;
    padding-inline: var(--space-4);
  }

  .app--fraction-add-subtract .fas-workspace {
    padding: var(--space-4);
  }

  .app--fraction-add-subtract .fas-expression {
    gap: clamp(0.3rem, 1.8vw, 0.65rem);
    font-size: clamp(1.9rem, 9vw, 2.6rem);
    margin: var(--space-2) 0 var(--space-4);
  }

  .app--fraction-add-subtract .fas-work {
    padding: var(--space-3);
  }

  .app--fraction-add-subtract .fas-start,
  .app--fraction-add-subtract .fas-check,
  .app--fraction-add-subtract .fas-next {
    width: 100%;
    min-height: 3.5rem;
  }

  .app--fraction-add-subtract .fas-actions {
    flex-direction: column;
  }

  .app--fraction-add-subtract .fas-actions .fas-check,
  .app--fraction-add-subtract .fas-actions .fas-skip {
    flex: 0 0 auto;
    width: 100%;
    min-height: 48px;
  }

  .app--fraction-add-subtract .fas-numpad {
    gap: 4px;
  }

  .app--fraction-add-subtract .fas-key {
    height: 44px;
    min-height: 44px;
    font-size: 1.1rem;
    border-radius: 10px;
  }

  .app--fraction-add-subtract .fas-key-del__label {
    display: none;
  }

  .app--fraction-add-subtract .fas-input__num,
  .app--fraction-add-subtract .fas-input__den,
  .app--fraction-add-subtract .fas-input__line {
    width: clamp(3.35rem, 15vw, 4.25rem);
  }

  .app--fraction-add-subtract .fas-input__num,
  .app--fraction-add-subtract .fas-input__den {
    height: 2.85rem;
    font-size: 1.55rem;
  }
}

@media (max-width: 520px) {
  .app--fraction-add-subtract .fas-tab {
    min-height: 48px;
    padding: 0.45rem 0.55rem;
    gap: 0.35rem;
  }

  .app--fraction-add-subtract .fas-tab__icon {
    font-size: 1rem;
  }

  .app--fraction-add-subtract .fas-workspace {
    padding: var(--space-3);
  }

  .app--fraction-add-subtract .fas-success,
  .app--fraction-add-subtract .fas-reveal {
    padding: var(--space-3);
  }
}

@media (max-width: 360px) {
  .app--fraction-add-subtract {
    padding-inline: var(--space-2);
  }

  .app--fraction-add-subtract .fas-tab__icon {
    display: none;
  }

  .app--fraction-add-subtract .fas-expression {
    font-size: 1.85rem;
  }

  .app--fraction-add-subtract .fas-input__num,
  .app--fraction-add-subtract .fas-input__den,
  .app--fraction-add-subtract .fas-input__line {
    width: 3.2rem;
  }
}

@media (hover: hover) and (pointer: fine) {
  .app--fraction-add-subtract .fas-back:hover {
    background: var(--primary-bg);
  }

  .app--fraction-add-subtract .fas-tab:hover:not(:disabled),
  .app--fraction-add-subtract .fas-card:hover,
  .app--fraction-add-subtract .fas-hint-btn:hover,
  .app--fraction-add-subtract .fas-skip:hover,
  .app--fraction-add-subtract .fas-key:hover {
    box-shadow: var(--shadow-md);
  }

  .app--fraction-add-subtract .fas-start:hover,
  .app--fraction-add-subtract .fas-check:hover,
  .app--fraction-add-subtract .fas-next:hover {
    background: var(--primary-h);
  }

  .app--fraction-add-subtract .fas-key:hover {
    border-color: color-mix(in srgb, var(--primary) 22%, var(--border));
    background: var(--primary-bg);
    transform: scale(1.04);
  }

  .app--fraction-add-subtract .fas-key--ok:hover {
    border-color: var(--success);
    background: color-mix(in srgb, var(--success) 85%, #000);
    color: var(--text-inv);
  }
}

@media (prefers-reduced-motion: reduce) {
  .app--fraction-add-subtract .fas-confetti .cp,
  .app--fraction-add-subtract .trainer-quiz-confetti .cp {
    animation: none;
  }

  .app--fraction-add-subtract .fas-tab {
    transition: none;
  }

  .app--fraction-add-subtract .fas-progress__fill {
    transition: none;
  }

  .app--fraction-add-subtract .fas-key {
    transition: none;
  }
}