/* Step 18: shared Memory Lab core. Uses locked semantic tokens only. */
.memory-lab[hidden],
.memory-lab__panel[hidden] {
  display: none;
}

.memory-lab {
  min-height: 0;
  height: 100%;
  display: grid;
  grid-template-rows: auto minmax(0, 1fr);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-xl);
  background: var(--surface-base);
  overflow: hidden;
}

.memory-lab__header {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: var(--space-4);
  align-items: center;
  padding: var(--space-3) var(--space-4);
  border-bottom: 1px solid var(--divider-default);
  background: var(--surface-subtle);
}

.memory-lab__identity {
  min-width: 0;
  display: grid;
  gap: 2px;
}

.memory-lab__title {
  font-size: var(--text-sm);
  font-weight: var(--weight-bold);
  color: var(--text-primary);
}

.memory-lab__summary {
  color: var(--text-muted);
  font-size: var(--text-xs);
}

.memory-lab__tabs {
  display: inline-grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: var(--space-1);
  padding: var(--space-1);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-lg);
  background: var(--surface-base);
}

.memory-lab__tab {
  min-height: var(--touch-target-min);
  min-width: 96px;
  padding: 0 var(--space-3);
  border: 1px solid transparent;
  border-radius: var(--radius-md);
  background: transparent;
  color: var(--text-secondary);
  font-weight: var(--weight-semibold);
  cursor: pointer;
}

.memory-lab__tab:hover,
.memory-lab__tab[aria-selected="true"] {
  border-color: var(--mode-accent);
  background: var(--mode-soft);
  color: var(--mode-soft-text);
}

.memory-lab__tab[aria-selected="true"] {
  box-shadow: inset 0 -3px 0 var(--mode-accent);
}

.memory-lab button:focus-visible,
.memory-lab [role="button"]:focus-visible,
.memory-lab input:focus-visible,
.memory-lab select:focus-visible {
  outline: 3px solid var(--focus-ring);
  outline-offset: 2px;
}

.memory-lab__workspace {
  min-height: 0;
  overflow: auto;
  overscroll-behavior: contain;
  padding: var(--space-5);
}

.memory-lab__panel {
  min-height: 100%;
}

.memory-panel-heading {
  max-width: 720px;
  margin-bottom: var(--space-5);
}

.memory-panel-heading__eyebrow {
  margin: 0 0 var(--space-2);
  color: var(--mode-soft-text);
  font-size: var(--text-xs);
  font-weight: var(--weight-bold);
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.memory-panel-heading h2 {
  margin: 0;
  font-size: clamp(1.55rem, 2.8vw, 2.15rem);
  line-height: 1.12;
  letter-spacing: -0.035em;
}

.memory-panel-heading p:last-child {
  margin: var(--space-2) 0 0;
  color: var(--text-secondary);
  line-height: var(--leading-normal);
}

.memory-learn-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--space-3);
}

.memory-learn-item {
  min-width: 0;
  display: grid;
  gap: var(--space-2);
  padding: var(--space-4);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-lg);
  background: var(--surface-canvas);
}

.memory-learn-item__header {
  display: flex;
  gap: var(--space-2);
  align-items: center;
  justify-content: space-between;
}

.memory-learn-item h3 {
  margin: 0;
  font-size: var(--text-md);
}

.memory-learn-item__kind {
  flex: 0 0 auto;
  padding: 2px var(--space-2);
  border-radius: var(--radius-pill);
  background: var(--mode-soft);
  color: var(--mode-soft-text);
  font-size: 0.68rem;
  font-weight: var(--weight-bold);
  text-transform: capitalize;
}

.memory-learn-item p {
  margin: 0;
  color: var(--text-secondary);
  line-height: var(--leading-normal);
}

.memory-learn-item__notation {
  margin-top: auto;
  padding: var(--space-3);
  border-radius: var(--radius-md);
  background: var(--surface-base);
  font-family: var(--font-math);
  font-size: var(--text-lg);
  text-align: center;
}

.memory-flashcard-layout {
  min-height: 100%;
  display: grid;
  grid-template-columns: minmax(260px, 0.68fr) minmax(340px, 1.1fr);
  gap: clamp(var(--space-5), 4vw, var(--space-7));
  align-items: center;
}

.memory-flashcard-copy {
  align-self: start;
}

.memory-flashcard-copy h2 {
  margin: var(--space-2) 0 var(--space-3);
  font-size: clamp(1.55rem, 2.8vw, 2.15rem);
  line-height: 1.12;
}

.memory-flashcard-copy p {
  margin: 0;
  color: var(--text-secondary);
  line-height: var(--leading-normal);
}

.memory-flashcard-stage {
  display: grid;
  gap: var(--space-3);
}

.memory-flashcard {
  min-height: 270px;
  display: grid;
  grid-template-rows: auto minmax(0, 1fr) auto;
  gap: var(--space-4);
  padding: var(--space-5);
  border: 1px solid var(--mode-accent);
  border-radius: var(--radius-xl);
  background: var(--surface-base);
  box-shadow: var(--shadow-raised);
  color: var(--text-primary);
  text-align: left;
  cursor: pointer;
}

.memory-flashcard:hover {
  background: var(--mode-soft);
}

.memory-flashcard__topline {
  display: flex;
  justify-content: space-between;
  gap: var(--space-3);
  color: var(--text-muted);
  font-size: var(--text-xs);
  font-weight: var(--weight-semibold);
}

.memory-flashcard__face {
  display: grid;
  align-content: center;
  justify-items: center;
  gap: var(--space-3);
  text-align: center;
}

.memory-flashcard__face-label {
  color: var(--mode-soft-text);
  font-size: var(--text-xs);
  font-weight: var(--weight-bold);
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.memory-flashcard__content {
  max-width: 18ch;
  font-family: var(--font-math);
  font-size: clamp(1.7rem, 4vw, 3rem);
  line-height: 1.18;
}

.memory-flashcard__prompt {
  color: var(--text-muted);
  font-size: var(--text-sm);
  text-align: center;
}

.memory-flashcard-rating {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--space-3);
}

.memory-flashcard-rating[hidden] {
  display: none;
}

.memory-rating-button,
.memory-match-reset {
  min-height: var(--touch-target-min);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-md);
  background: var(--surface-base);
  color: var(--text-secondary);
  font-weight: var(--weight-semibold);
  cursor: pointer;
}

.memory-rating-button:hover,
.memory-match-reset:hover {
  border-color: var(--mode-accent);
  background: var(--mode-soft);
  color: var(--mode-soft-text);
}

.memory-rating-button--know {
  border-color: var(--feedback-correct-accent);
  color: var(--feedback-correct-ink);
}

.memory-rating-button--not-yet {
  border-color: var(--feedback-warning-accent);
  color: var(--feedback-warning-ink);
}

.memory-engine-status {
  min-height: 1.4em;
  margin: 0;
  color: var(--text-muted);
  font-size: var(--text-sm);
}

.memory-match-layout {
  min-height: 100%;
  display: grid;
  grid-template-rows: auto minmax(0, 1fr) auto;
  gap: var(--space-4);
}

.memory-match-heading {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: var(--space-4);
}

.memory-match-heading h2 {
  margin: var(--space-1) 0 0;
  font-size: clamp(1.55rem, 2.8vw, 2.15rem);
}

.memory-match-heading p {
  margin: var(--space-1) 0 0;
  color: var(--text-secondary);
}

.memory-match-progress {
  color: var(--text-muted);
  font-size: var(--text-sm);
  font-variant-numeric: tabular-nums;
}

.memory-match-board {
  min-height: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--space-5);
  align-content: center;
}

.memory-match-column {
  display: grid;
  gap: var(--space-3);
}

.memory-match-column__label {
  color: var(--text-muted);
  font-size: var(--text-xs);
  font-weight: var(--weight-bold);
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.memory-match-option {
  min-height: 58px;
  width: 100%;
  padding: var(--space-3) var(--space-4);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-lg);
  background: var(--surface-base);
  color: var(--text-primary);
  font-family: var(--font-math);
  font-size: var(--text-md);
  text-align: left;
  cursor: pointer;
}

.memory-match-option:hover:not(:disabled),
.memory-match-option[aria-pressed="true"] {
  border-color: var(--mode-accent);
  background: var(--mode-soft);
  color: var(--mode-soft-text);
}

.memory-match-option[data-match-state="matched"] {
  border-color: var(--feedback-correct-accent);
  background: var(--feedback-correct-soft);
  color: var(--feedback-correct-ink);
  opacity: 0.8;
}

.memory-match-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
}

.memory-match-reset {
  padding: 0 var(--space-4);
}

@media (max-width: 900px) {
  .memory-lab__header {
    grid-template-columns: 1fr;
  }

  .memory-lab__tabs {
    width: 100%;
  }

  .memory-lab__tab {
    min-width: 0;
  }

  .memory-flashcard-layout {
    grid-template-columns: minmax(220px, 0.65fr) minmax(300px, 1fr);
  }
}

@media (max-width: 680px) {
  .memory-lab__workspace {
    padding: var(--space-4);
  }

  .memory-learn-list,
  .memory-flashcard-layout,
  .memory-match-board {
    grid-template-columns: 1fr;
  }

  .memory-learn-list {
    gap: var(--space-2);
  }

  .memory-flashcard-layout {
    align-content: start;
  }

  .memory-flashcard-copy {
    display: none;
  }

  .memory-flashcard {
    min-height: 245px;
  }

  .memory-match-board {
    align-content: start;
    gap: var(--space-4);
  }

  .memory-match-heading,
  .memory-match-footer {
    align-items: flex-start;
  }
}

.memory-learn-footer {
  display: flex;
  justify-content: flex-end;
  margin-top: var(--space-4);
}

.memory-learn-complete {
  min-height: var(--touch-target-min);
  padding: 0 var(--space-4);
  border: 1px solid var(--mode-accent);
  border-radius: var(--radius-md);
  background: var(--mode-accent);
  color: var(--mode-accent-text);
  font-weight: var(--weight-semibold);
  cursor: pointer;
}

.memory-learn-complete:hover {
  box-shadow: var(--shadow-raised);
}

/* Step 19: reusable Memory Lab games. */
.memory-game-panel[hidden] {
  display: none;
}

.memory-games-layout {
  min-height: 100%;
  display: grid;
  grid-template-rows: auto minmax(0, 1fr);
  gap: var(--space-4);
}

.memory-games-heading {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(420px, 0.9fr);
  gap: var(--space-5);
  align-items: end;
}

.memory-games-heading h2,
.memory-single-game__heading h3,
.memory-match-heading h3 {
  margin: var(--space-1) 0 0;
  line-height: 1.16;
  letter-spacing: -0.025em;
}

.memory-games-heading h2 {
  font-size: clamp(1.45rem, 2.5vw, 1.95rem);
}

.memory-single-game__heading h3,
.memory-match-heading h3 {
  font-size: clamp(1.25rem, 2.1vw, 1.65rem);
}

.memory-games-heading p:last-child,
.memory-single-game__heading p:last-child {
  margin: var(--space-2) 0 0;
  color: var(--text-secondary);
  line-height: var(--leading-normal);
}

.memory-game-tabs {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: var(--space-1);
  padding: var(--space-1);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-lg);
  background: var(--surface-subtle);
}

.memory-game-tab {
  min-height: var(--touch-target-min);
  min-width: 0;
  padding: 0 var(--space-2);
  border: 1px solid transparent;
  border-radius: var(--radius-md);
  background: transparent;
  color: var(--text-secondary);
  font-size: var(--text-xs);
  font-weight: var(--weight-semibold);
  cursor: pointer;
}

.memory-game-tab:hover,
.memory-game-tab[aria-selected="true"] {
  border-color: var(--mode-accent);
  background: var(--mode-soft);
  color: var(--mode-soft-text);
}

.memory-game-tab[aria-selected="true"] {
  box-shadow: inset 0 -3px 0 var(--mode-accent);
}

.memory-game-stage {
  min-height: 0;
  border: 1px solid var(--border-default);
  border-radius: var(--radius-xl);
  background: var(--surface-canvas);
  overflow: hidden;
}

.memory-game-panel {
  min-height: 100%;
  padding: var(--space-4);
}

.memory-single-game,
.memory-sort-layout {
  min-height: 100%;
  max-width: 880px;
  margin: 0 auto;
  display: grid;
  align-content: center;
  gap: var(--space-5);
}

.memory-single-game__heading {
  max-width: 680px;
}

.memory-build-expression,
.memory-game-expression {
  min-height: 116px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-3);
  padding: var(--space-4);
  border: 1px solid var(--mode-accent);
  border-radius: var(--radius-xl);
  background: var(--surface-base);
  font-family: var(--font-math);
  font-size: clamp(1.65rem, 4vw, 2.65rem);
  text-align: center;
}

.memory-build-slots {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
}

.memory-build-slot {
  min-width: 58px;
  min-height: 54px;
  display: inline-grid;
  place-items: center;
  padding: 0 var(--space-2);
  border: 1px dashed var(--mode-accent);
  border-radius: var(--radius-md);
  background: var(--mode-soft);
  color: var(--mode-soft-text);
}

.memory-game-token-bank,
.memory-game-choice-grid,
.memory-impostor-options {
  display: grid;
  gap: var(--space-3);
}

.memory-game-token-bank {
  grid-template-columns: repeat(5, minmax(0, 1fr));
}

.memory-game-choice-grid,
.memory-impostor-options {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.memory-game-token,
.memory-game-choice,
.memory-impostor-option,
.memory-sort-item,
.memory-sort-bucket {
  min-height: var(--touch-target-min);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-lg);
  background: var(--surface-base);
  color: var(--text-primary);
  cursor: pointer;
}

.memory-game-token,
.memory-game-choice {
  padding: var(--space-3);
  font-family: var(--font-math);
  font-size: var(--text-lg);
  text-align: center;
}

.memory-impostor-option {
  min-height: 72px;
  padding: var(--space-3) var(--space-4);
  font-family: var(--font-math);
  font-size: var(--text-md);
  text-align: left;
}

.memory-game-token:hover:not(:disabled),
.memory-game-choice:hover:not(:disabled),
.memory-impostor-option:hover:not(:disabled),
.memory-sort-item:hover:not(:disabled),
.memory-sort-bucket:hover:not(:disabled),
.memory-game-choice[aria-pressed="true"],
.memory-impostor-option[aria-pressed="true"],
.memory-sort-item[aria-pressed="true"] {
  border-color: var(--mode-accent);
  background: var(--mode-soft);
  color: var(--mode-soft-text);
}

.memory-game-token:disabled,
.memory-game-choice:disabled,
.memory-impostor-option:disabled,
.memory-sort-item:disabled,
.memory-sort-bucket:disabled,
.memory-game-primary:disabled,
.memory-game-secondary:disabled {
  cursor: default;
  opacity: 0.62;
}

.memory-game-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
}

.memory-game-actions {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: var(--space-2);
}

.memory-game-primary,
.memory-game-secondary {
  min-height: var(--touch-target-min);
  padding: 0 var(--space-4);
  border-radius: var(--radius-md);
  font-weight: var(--weight-semibold);
  cursor: pointer;
}

.memory-game-primary {
  border: 1px solid var(--mode-accent);
  background: var(--mode-accent);
  color: var(--mode-accent-text);
}

.memory-game-secondary {
  border: 1px solid var(--border-default);
  background: var(--surface-base);
  color: var(--text-secondary);
}

.memory-game-primary:hover:not(:disabled),
.memory-game-secondary:hover:not(:disabled) {
  box-shadow: var(--shadow-raised);
}

.memory-sort-layout {
  position: relative;
}

.memory-sort-progress {
  justify-self: end;
  color: var(--text-muted);
  font-size: var(--text-sm);
  font-variant-numeric: tabular-nums;
}

.memory-sort-workspace {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(260px, 0.78fr);
  gap: var(--space-5);
}

.memory-sort-items,
.memory-sort-buckets {
  display: grid;
  gap: var(--space-2);
  margin-top: var(--space-2);
}

.memory-sort-items {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.memory-sort-item {
  padding: var(--space-3);
  font-family: var(--font-math);
  font-size: var(--text-md);
  text-align: left;
}

.memory-sort-bucket {
  display: grid;
  gap: var(--space-1);
  padding: var(--space-3) var(--space-4);
  text-align: left;
}

.memory-sort-bucket__title {
  font-weight: var(--weight-bold);
}

.memory-sort-bucket__description {
  color: var(--text-muted);
  font-size: var(--text-xs);
  line-height: var(--leading-normal);
}

.memory-match-layout {
  padding: 0;
}

@media (max-width: 1100px) {
  .memory-games-heading {
    grid-template-columns: 1fr;
    align-items: start;
  }
}

@media (max-width: 680px) {
  .memory-game-panel {
    padding: var(--space-3);
  }

  .memory-games-heading {
    gap: var(--space-3);
  }

  .memory-game-tabs {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .memory-single-game,
  .memory-sort-layout {
    align-content: start;
    gap: var(--space-4);
  }

  .memory-game-token-bank {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .memory-game-choice-grid,
  .memory-impostor-options,
  .memory-sort-workspace,
  .memory-sort-items {
    grid-template-columns: 1fr;
  }

  .memory-build-expression {
    flex-wrap: wrap;
    min-height: 104px;
    font-size: clamp(1.4rem, 7vw, 2rem);
  }

  .memory-build-slot {
    min-width: 48px;
  }

  .memory-game-footer,
  .memory-match-footer {
    align-items: flex-start;
    flex-direction: column;
  }

  .memory-game-actions {
    width: 100%;
    justify-content: stretch;
  }

  .memory-game-actions > button {
    flex: 1 1 auto;
  }
}

/* Step 19 visual compacting: keep the retrieval object above the fold. */
.memory-games-heading {
  gap: var(--space-3);
}

.memory-games-heading h2 {
  font-size: var(--text-lg);
  letter-spacing: -0.015em;
}

.memory-games-heading p:last-child {
  margin-top: var(--space-1);
  font-size: var(--text-sm);
}

.memory-game-panel {
  padding: var(--space-3) var(--space-4);
}

.memory-single-game,
.memory-sort-layout {
  gap: var(--space-4);
}

.memory-single-game__heading h3,
.memory-match-heading h3 {
  font-size: clamp(1.2rem, 1.9vw, 1.5rem);
}

.memory-build-expression,
.memory-game-expression {
  min-height: 96px;
}

@media (max-width: 680px) {
  .memory-games-heading > div:first-child {
    display: none;
  }

  .memory-games-layout {
    gap: var(--space-2);
  }

  .memory-game-panel {
    padding: var(--space-3);
  }

  .memory-game-tabs {
    position: sticky;
    top: 0;
    z-index: 1;
  }

  .memory-single-game__heading p:last-child,
  .memory-match-heading p {
    font-size: var(--text-sm);
  }
}

/* Step 20: Review, Rapid Recall, Diagram Recall and Memory Mix. */
.memory-lab__tabs {
  grid-template-columns: repeat(4, minmax(0, 1fr));
}

.memory-review-task-panel[hidden] {
  display: none;
}

.memory-review-layout {
  min-height: 100%;
  display: grid;
  grid-template-rows: auto minmax(0, 1fr);
  gap: var(--space-4);
}

.memory-review-heading {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: var(--space-4);
  align-items: end;
}

.memory-review-heading h2 {
  margin: var(--space-1) 0 0;
  font-size: clamp(1.4rem, 2.4vw, 1.9rem);
  line-height: 1.14;
  letter-spacing: -0.025em;
}

.memory-review-heading p:last-child {
  max-width: 680px;
  margin: var(--space-1) 0 0;
  color: var(--text-secondary);
  font-size: var(--text-sm);
  line-height: var(--leading-normal);
}

.memory-review-mode-tabs {
  display: inline-grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: var(--space-1);
  padding: var(--space-1);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-lg);
  background: var(--surface-subtle);
}

.memory-review-mode-tab {
  min-height: var(--touch-target-min);
  min-width: 110px;
  padding: 0 var(--space-3);
  border: 1px solid transparent;
  border-radius: var(--radius-md);
  background: transparent;
  color: var(--text-secondary);
  font-size: var(--text-xs);
  font-weight: var(--weight-semibold);
  cursor: pointer;
}

.memory-review-mode-tab:hover,
.memory-review-mode-tab[aria-selected="true"] {
  border-color: var(--mode-accent);
  background: var(--mode-soft);
  color: var(--mode-soft-text);
}

.memory-review-mode-tab[aria-selected="true"] {
  box-shadow: inset 0 -3px 0 var(--mode-accent);
}

.memory-review-stage {
  min-height: 0;
  display: grid;
  grid-template-rows: auto minmax(0, 1fr) auto;
  border: 1px solid var(--border-default);
  border-radius: var(--radius-xl);
  background: var(--surface-canvas);
  overflow: hidden;
}

.memory-mix__topline,
.memory-mix__footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  padding: var(--space-3) var(--space-4);
  background: var(--surface-base);
}

.memory-mix__topline {
  border-bottom: 1px solid var(--divider-default);
}

.memory-mix__footer {
  border-top: 1px solid var(--divider-default);
}

.memory-mix__counter {
  color: var(--text-muted);
  font-size: var(--text-xs);
  font-weight: var(--weight-semibold);
  font-variant-numeric: tabular-nums;
}

.memory-mix__task {
  color: var(--mode-soft-text);
  font-size: var(--text-sm);
}

.memory-review-task-stage {
  min-height: 0;
  overflow: auto;
  overscroll-behavior: contain;
}

.memory-review-task-panel {
  min-height: 100%;
  padding: var(--space-4);
}

#memory-lab-panel-review[data-review-mode="rapid"] .memory-mix__topline,
#memory-lab-panel-review[data-review-mode="rapid"] .memory-mix__footer,
#memory-lab-panel-review[data-review-mode="diagram"] .memory-mix__topline,
#memory-lab-panel-review[data-review-mode="diagram"] .memory-mix__footer {
  display: none;
}

.memory-rapid-layout {
  min-height: 100%;
  max-width: 860px;
  margin: 0 auto;
  display: grid;
  grid-template-rows: auto auto minmax(0, 1fr) auto;
  gap: var(--space-4);
  align-content: center;
}

.memory-rapid-topline {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
}

.memory-rapid-timer-controls {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.memory-rapid-timer {
  min-width: 3ch;
  color: var(--feedback-warning-ink);
  font-weight: var(--weight-bold);
  font-variant-numeric: tabular-nums;
  text-align: right;
}

.memory-rapid-options,
.memory-diagram-options {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--space-3);
  align-content: center;
}

.memory-rapid-option,
.memory-diagram-choice {
  min-height: 64px;
  padding: var(--space-3) var(--space-4);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-lg);
  background: var(--surface-base);
  color: var(--text-primary);
  font-family: var(--font-math);
  font-size: var(--text-md);
  text-align: left;
  cursor: pointer;
}

.memory-rapid-option:hover:not(:disabled),
.memory-diagram-choice:hover:not(:disabled) {
  border-color: var(--mode-accent);
  background: var(--mode-soft);
  color: var(--mode-soft-text);
}

.memory-rapid-option:disabled,
.memory-diagram-choice:disabled {
  cursor: default;
  opacity: 0.68;
}

.memory-diagram-layout {
  min-height: 100%;
  display: grid;
  grid-template-columns: minmax(360px, 1.15fr) minmax(300px, 0.85fr);
  gap: var(--space-5);
  align-items: center;
}

.memory-diagram-recall__canvas {
  min-height: 300px;
  display: grid;
  place-items: center;
  padding: var(--space-3);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-xl);
  background: var(--surface-base);
}

.memory-diagram-recall__svg {
  width: 100%;
  max-width: 620px;
  height: auto;
  overflow: visible;
}

.memory-diagram-recall__element,
.memory-diagram-recall__connector {
  vector-effect: non-scaling-stroke;
}

.memory-diagram-recall__element--axis {
  stroke: var(--border-strong);
  stroke-width: 1.5;
}

.memory-diagram-recall__element--curve {
  stroke: var(--text-primary);
  stroke-width: 4;
}

.memory-diagram-recall__element--tangent {
  stroke: var(--mode-accent);
  stroke-width: 3;
}

.memory-diagram-recall__element--point {
  fill: var(--mode-accent);
  stroke: var(--surface-base);
  stroke-width: 2;
}

.memory-diagram-recall__connector {
  stroke: var(--text-muted);
  stroke-width: 1.5;
  stroke-dasharray: 4 4;
}

.memory-diagram-recall__marker {
  fill: var(--surface-base);
  stroke: var(--mode-accent);
  stroke-width: 2;
}

.memory-diagram-recall__marker-text {
  fill: var(--mode-soft-text);
  font-family: var(--font-ui);
  font-size: 14px;
  font-weight: var(--weight-bold);
}

.memory-diagram-recall__prompt {
  display: grid;
  gap: var(--space-4);
  align-content: center;
}

@media (max-width: 1000px) {
  .memory-review-heading {
    grid-template-columns: 1fr;
    align-items: start;
  }

  .memory-review-mode-tabs {
    width: 100%;
  }

  .memory-review-mode-tab {
    min-width: 0;
  }

  .memory-diagram-layout {
    grid-template-columns: minmax(300px, 1fr) minmax(260px, 0.8fr);
  }
}

@media (max-width: 680px) {
  .memory-review-layout {
    gap: var(--space-2);
  }

  .memory-review-heading > div:first-child {
    display: none;
  }

  .memory-review-mode-tabs {
    position: sticky;
    top: 0;
    z-index: 2;
  }

  .memory-review-task-panel {
    padding: var(--space-3);
  }

  .memory-mix__topline,
  .memory-mix__footer {
    align-items: flex-start;
    padding: var(--space-2) var(--space-3);
  }

  .memory-mix__footer {
    flex-direction: column;
  }

  .memory-rapid-layout {
    align-content: start;
    gap: var(--space-3);
  }

  .memory-rapid-options,
  .memory-diagram-options,
  .memory-diagram-layout {
    grid-template-columns: 1fr;
  }

  .memory-diagram-recall__canvas {
    min-height: 220px;
    padding: var(--space-2);
  }
}

/* Step 20 fit pass: keep Review chrome fixed while retrieval content scrolls internally. */
.memory-lab__panel[data-memory-lab-panel="review"] {
  min-height: 0;
  height: 100%;
}

.memory-review-layout {
  min-height: 0;
  height: 100%;
}

@media (max-width: 680px) {
  .memory-lab__tabs {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .memory-lab__tab {
    min-width: 0;
    padding: 0 var(--space-2);
    font-size: var(--text-xs);
  }
}