body.nback-page {
    max-width: 1180px;
}

body.nback-page #main-content {
    padding-right: 0;
    padding-left: 0;
}

.nback-tool {
    --nback-panel: var(--bg-primary);
    --nback-ink: var(--text-color);
    --nback-muted: var(--date-color);
    --nback-line: var(--border-color);
    --nback-field: var(--bg-secondary);
    --nback-field-strong: var(--bg-tertiary);
    --nback-progress-bg: var(--progress-bg);
    --nback-green: #198754;
    --nback-green-soft: rgba(25, 135, 84, 0.16);
    --nback-red: #b02a37;
    --nback-red-soft: rgba(176, 42, 55, 0.14);
    --nback-gold: #8a6d3b;
    --nback-shadow: 0 18px 42px rgba(0, 0, 0, 0.08);
    margin: 1.25rem 0 2rem;
    color: var(--nback-ink);
}

.nback-tool,
.nback-tool * {
    box-sizing: border-box;
}

.nback-tool button,
.nback-tool input,
.nback-tool select {
    font: inherit;
}

.nback-tool button {
    border: 0;
    cursor: pointer;
    touch-action: manipulation;
    user-select: none;
}

.nback-tool :focus-visible {
    outline: 3px solid var(--focus-outline-color);
    outline-offset: 2px;
}

.nback-tool [hidden] {
    display: none !important;
}

.nback-tool .visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    overflow: hidden;
    clip: rect(0 0 0 0);
    clip-path: inset(50%);
    white-space: nowrap;
}

.nback-tool .app-shell {
    display: grid;
    grid-template-columns: minmax(0, 1040px);
    justify-content: center;
    gap: 14px;
    width: 100%;
}

.nback-tool .game-panel,
.nback-tool .details-panel {
    background: var(--nback-panel);
    border: 1px solid var(--nback-line);
    border-radius: 6px;
    box-shadow: var(--nback-shadow);
}

.nback-tool .game-panel {
    display: flex;
    flex-direction: column;
    min-width: 0;
    padding: 24px;
}

.nback-tool .details-panel {
    padding: 0;
}

.nback-tool .details-panel summary {
    cursor: pointer;
    padding: 14px 18px;
    color: var(--nback-muted);
    font-weight: 850;
}

.nback-tool .details-content {
    display: flex;
    flex-direction: column;
    gap: 18px;
    padding: 20px;
    border-top: 1px solid var(--nback-line);
}

.nback-tool .topbar,
.nback-tool .history-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
}

.nback-tool .eyebrow {
    margin: 0 0 4px;
    color: var(--accent-color);
    font-size: 0.78rem;
    font-weight: 800;
    letter-spacing: 0;
    text-transform: uppercase;
}

.nback-tool h1,
.nback-tool h2,
.nback-tool p {
    margin-top: 0;
}

.nback-tool h1 {
    margin-bottom: 0;
    padding: 0;
    border: 0;
    color: var(--nback-ink);
    font-size: clamp(2rem, 4vw, 4.75rem);
    line-height: 0.95;
    letter-spacing: 0;
}

.nback-tool h2 {
    margin-bottom: 12px;
    color: var(--nback-ink);
    font-size: 0.95rem;
    letter-spacing: 0;
}

.nback-tool .level-pill {
    display: grid;
    min-width: 92px;
    min-height: 92px;
    place-items: center;
    border: 1px solid var(--nback-line);
    border-radius: 6px;
    background: var(--nback-field);
    color: var(--accent-color);
}

.nback-tool .level-pill span {
    font-size: 0.72rem;
    font-weight: 800;
}

.nback-tool .level-pill strong {
    font-size: 2.9rem;
    line-height: 0.9;
}

.nback-tool .player-note {
    margin: 14px 0 0;
    color: var(--nback-muted);
    font-size: 0.95rem;
    font-weight: 700;
    line-height: 1.4;
}

.nback-tool .progress-stack {
    display: grid;
    gap: 10px;
    margin: 24px 0;
}

.nback-tool .progress-line {
    display: grid;
    grid-template-columns: 58px minmax(0, 1fr);
    align-items: center;
    gap: 12px;
}

.nback-tool .progress-line > span,
.nback-tool .stimulus-card span {
    display: block;
    color: var(--nback-muted);
    font-size: 0.76rem;
    font-weight: 750;
    letter-spacing: 0;
    text-transform: uppercase;
}

.nback-tool .round-progress,
.nback-tool .difficulty-progress {
    height: 12px;
    overflow: hidden;
    background: var(--nback-progress-bg);
    border-radius: 999px;
}

.nback-tool .round-progress span,
.nback-tool .difficulty-progress span {
    display: block;
    width: 0%;
    height: 100%;
    transition: width 180ms ease;
}

.nback-tool .round-progress span {
    background: var(--accent-color);
}

.nback-tool .difficulty-progress span {
    background: var(--nback-green);
}

.nback-tool .progress-line.is-break {
    align-items: start;
}

.nback-tool .break-progress {
    display: grid;
    gap: 6px;
}

.nback-tool .break-progress p {
    margin: 0;
    color: var(--nback-muted);
    font-size: 0.82rem;
    line-height: 1.35;
}

.nback-tool .level-up-notice {
    margin: -8px 0 18px;
    padding: 10px 12px;
    border: 1px solid var(--nback-line);
    border-left: 4px solid var(--accent-color);
    border-radius: 6px;
    background: var(--nback-field);
    color: var(--nback-ink);
    font-size: 0.88rem;
    font-weight: 850;
}

.nback-tool .play-area {
    display: grid;
    grid-template-columns: 1fr;
    gap: 14px;
    min-height: 0;
    flex: 1;
}

.nback-tool .grid {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 12px;
    align-self: stretch;
    width: min(100%, 72vh);
    max-width: 680px;
    aspect-ratio: 1;
    margin: auto;
}

.nback-tool .cell {
    display: grid;
    min-width: 0;
    min-height: 0;
    place-items: center;
    border: 2px solid var(--nback-line);
    border-radius: 6px;
    background: var(--nback-field-strong);
    color: #fff;
    font-size: clamp(1.5rem, 5vw, 3.6rem);
    font-weight: 900;
    line-height: 1;
    text-shadow: 0 1px 7px rgba(0, 0, 0, 0.36);
    transition: transform 120ms ease, background 120ms ease, border-color 120ms ease, box-shadow 120ms ease;
}

.nback-tool .cell.is-active {
    border-color: var(--accent-color);
    background: var(--active-color, #36a566);
    box-shadow: inset 0 0 0 8px rgba(255, 255, 255, 0.34);
    transform: scale(0.96);
}

.nback-tool .cell.is-match {
    border-color: var(--nback-gold);
}

.nback-tool .cell.is-pulse {
    animation: nback-trial-pulse 420ms ease-out;
}

.nback-tool .grid.is-muted .cell {
    background: var(--nback-field);
    border-color: var(--nback-line);
    box-shadow: none;
}

.nback-tool .controls-panel {
    display: grid;
    grid-template-columns: auto minmax(0, 1fr) auto;
    align-items: center;
    gap: 12px;
    width: min(100%, 72vh);
    max-width: 680px;
    min-width: 0;
    margin: 0 auto;
}

.nback-tool .stimulus-card {
    display: grid;
    min-width: 86px;
    min-height: 48px;
    place-items: center;
    border: 1px solid var(--nback-line);
    border-radius: 6px;
    background: var(--nback-field);
}

.nback-tool .stimulus-card span {
    align-self: end;
}

.nback-tool .stimulus-card strong {
    align-self: start;
    font-size: 1.2rem;
    line-height: 1;
}

.nback-tool .stimulus-card.is-visual-cue {
    min-width: 104px;
    background: var(--cue-color, var(--nback-field));
    color: #fff;
}

.nback-tool .stimulus-card.is-visual-cue span,
.nback-tool .stimulus-card.is-visual-cue strong {
    color: #fff;
    text-shadow: 0 1px 6px rgba(0, 0, 0, 0.35);
}

.nback-tool .stimulus-card.is-cue-pulse {
    animation: nback-cue-pulse 420ms ease-out;
}

.nback-tool .match-controls {
    display: grid;
    grid-template-columns: repeat(var(--stream-count, 1), minmax(0, 1fr));
    gap: 12px;
}

.nback-tool .match-button,
.nback-tool .primary-actions button,
.nback-tool .history-header button {
    min-height: 48px;
    border: 1px solid var(--nback-line);
    border-radius: 6px;
    background: var(--nback-field);
    color: var(--nback-ink);
    font-weight: 800;
}

.nback-tool .match-button {
    display: grid;
    grid-template-columns: 34px minmax(0, 1fr);
    align-items: center;
    gap: 8px;
    padding: 8px 10px;
    text-align: left;
    touch-action: manipulation;
}

.nback-tool .match-button span {
    display: grid;
    width: 34px;
    height: 30px;
    place-items: center;
    border-radius: 4px;
    background: var(--text-color);
    color: #fff;
}

.nback-tool .match-button.is-selected {
    border-color: var(--accent-color);
    background: color-mix(in srgb, var(--accent-color) 12%, var(--nback-field));
}

.nback-tool .match-button.is-correct {
    border-color: var(--nback-green);
    background: var(--nback-green-soft);
}

.nback-tool .match-button.is-wrong {
    border-color: var(--nback-red);
    background: var(--nback-red-soft);
}

.nback-tool .match-button:disabled {
    cursor: default;
    opacity: 0.42;
}

.nback-tool .primary-actions {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px;
    min-width: 190px;
}

.nback-tool .primary-actions button:first-child {
    background: var(--accent-color);
    color: #fff;
}

.nback-tool .primary-actions button:first-child:hover {
    background: var(--hover-color);
}

.nback-tool .settings,
.nback-tool .hotkeys,
.nback-tool .progression,
.nback-tool .daily-practice,
.nback-tool .history {
    padding-top: 16px;
    border-top: 1px solid var(--nback-line);
}

.nback-tool .settings {
    padding-top: 0;
    border-top: 0;
}

.nback-tool .load-grid {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 8px;
    margin-bottom: 14px;
}

.nback-tool .load-grid div,
.nback-tool .practice-stats div {
    min-width: 0;
    padding: 10px;
    border: 1px solid var(--nback-line);
    border-radius: 6px;
    background: var(--nback-field);
}

.nback-tool .load-grid span,
.nback-tool .practice-stats span {
    display: block;
    color: var(--nback-muted);
    font-size: 0.72rem;
    font-weight: 800;
    text-transform: uppercase;
}

.nback-tool .load-grid strong,
.nback-tool .practice-stats strong {
    display: block;
    margin-top: 4px;
}

.nback-tool .load-grid strong {
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.nback-tool label {
    display: grid;
    gap: 7px;
    margin-bottom: 12px;
    color: var(--nback-muted);
    font-size: 0.86rem;
    font-weight: 750;
}

.nback-tool .training-options {
    display: grid;
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr) auto;
    align-items: end;
    gap: 12px;
}

.nback-tool .training-options label {
    margin-bottom: 0;
}

.nback-tool input,
.nback-tool select {
    width: 100%;
    min-height: 42px;
    padding: 8px 10px;
    border: 1px solid var(--nback-line);
    border-radius: 6px;
    background: var(--nback-field);
    color: var(--nback-ink);
}

.nback-tool .toggle-row {
    grid-template-columns: 18px minmax(0, 1fr);
    align-items: center;
    min-height: 42px;
    padding-bottom: 2px;
    color: var(--nback-ink);
}

.nback-tool .toggle-row input {
    width: 18px;
    min-height: 18px;
}

.nback-tool dl {
    display: grid;
    gap: 8px;
    margin: 0;
}

.nback-tool dl div {
    display: grid;
    grid-template-columns: 74px minmax(0, 1fr);
    align-items: center;
    gap: 10px;
}

.nback-tool dt {
    display: grid;
    min-height: 30px;
    place-items: center;
    border-radius: 4px;
    background: var(--text-color);
    color: #fff;
    font-size: 0.78rem;
    font-weight: 850;
}

.nback-tool dd {
    margin: 0;
    color: var(--nback-muted);
}

.nback-tool .progression p,
.nback-tool .daily-practice p {
    color: var(--nback-muted);
    line-height: 1.45;
}

.nback-tool .progress-bars {
    display: grid;
    gap: 10px;
}

.nback-tool .metric {
    display: grid;
    gap: 6px;
}

.nback-tool .metric-row {
    display: flex;
    justify-content: space-between;
    gap: 10px;
    color: var(--nback-muted);
    font-size: 0.82rem;
    font-weight: 750;
}

.nback-tool .bar {
    height: 9px;
    overflow: hidden;
    border-radius: 999px;
    background: var(--nback-progress-bg);
}

.nback-tool .bar span {
    display: block;
    width: 0%;
    height: 100%;
    background: var(--accent-color);
    transition: width 180ms ease;
}

.nback-tool .daily-practice-bar span {
    background: var(--nback-green);
}

.nback-tool .practice-stats {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 8px;
    margin-top: 12px;
}

.nback-tool .practice-stats strong {
    font-size: 1.25rem;
}

.nback-tool .history-header h2 {
    margin-bottom: 0;
}

.nback-tool .history-header button {
    min-height: 34px;
    padding: 0 12px;
    border-color: var(--nback-red);
    background: var(--nback-red-soft);
    color: var(--nback-red);
}

.nback-tool .history-table-wrap {
    margin-top: 12px;
    overflow-x: auto;
    border: 1px solid var(--nback-line);
    border-radius: 6px;
    background: var(--nback-field);
}

.nback-tool .history-table {
    width: 100%;
    min-width: 620px;
    border-collapse: collapse;
    font-size: 0.82rem;
}

.nback-tool .history-table th,
.nback-tool .history-table td {
    padding: 10px 9px;
    border-bottom: 1px solid var(--nback-line);
    text-align: left;
    white-space: nowrap;
}

.nback-tool .history-table th {
    color: var(--nback-muted);
    font-size: 0.72rem;
    font-weight: 850;
    text-transform: uppercase;
}

.nback-tool .history-table tbody tr:last-child td {
    border-bottom: 0;
}

.nback-tool .history-table td {
    color: var(--nback-ink);
    font-weight: 700;
}

.nback-tool .history-table td.is-muted {
    color: var(--nback-muted);
}

@keyframes nback-trial-pulse {
    0% {
        box-shadow: 0 0 0 0 color-mix(in srgb, var(--accent-color) 42%, transparent), inset 0 0 0 12px rgba(255, 255, 255, 0.55);
        transform: scale(0.9);
    }

    58% {
        box-shadow: 0 0 0 12px color-mix(in srgb, var(--accent-color) 14%, transparent), inset 0 0 0 6px rgba(255, 255, 255, 0.34);
        transform: scale(0.98);
    }

    100% {
        box-shadow: inset 0 0 0 8px rgba(255, 255, 255, 0.34);
        transform: scale(0.96);
    }
}

@keyframes nback-cue-pulse {
    0% {
        box-shadow: 0 0 0 0 rgba(47, 111, 159, 0.42), inset 0 0 0 9px rgba(255, 255, 255, 0.42);
        transform: scale(0.94);
    }

    60% {
        box-shadow: 0 0 0 10px rgba(47, 111, 159, 0.14), inset 0 0 0 4px rgba(255, 255, 255, 0.25);
        transform: scale(1);
    }

    100% {
        box-shadow: none;
        transform: scale(1);
    }
}

@media (prefers-color-scheme: dark) {
    .nback-tool {
        --nback-green-soft: rgba(25, 135, 84, 0.18);
        --nback-red-soft: rgba(176, 42, 55, 0.18);
        --nback-shadow: 0 18px 42px rgba(0, 0, 0, 0.28);
    }
}

html[data-theme='dark'] .nback-tool {
    --nback-green-soft: rgba(25, 135, 84, 0.18);
    --nback-red-soft: rgba(176, 42, 55, 0.18);
    --nback-shadow: 0 18px 42px rgba(0, 0, 0, 0.28);
}

@media (max-width: 1050px) {
    .nback-tool .app-shell {
        grid-template-columns: 1fr;
    }

    .nback-tool .details-panel {
        overflow: visible;
    }
}

@media (max-width: 760px) {
    body.nback-page {
        padding: 8px;
    }

    body.nback-page #main-content {
        padding-right: 0;
        padding-left: 0;
    }

    .nback-tool .app-shell {
        gap: 10px;
    }

    .nback-tool .game-panel {
        min-height: calc(100dvh - 96px);
        padding: 12px;
    }

    .nback-tool .details-content {
        padding: 14px;
    }

    .nback-tool .topbar {
        align-items: center;
        gap: 10px;
    }

    .nback-tool .eyebrow {
        margin-bottom: 2px;
        font-size: 0.68rem;
    }

    .nback-tool h1 {
        font-size: 2rem;
    }

    .nback-tool .level-pill {
        min-width: 62px;
        min-height: 62px;
    }

    .nback-tool .level-pill strong {
        font-size: 1.9rem;
    }

    .nback-tool .player-note {
        margin-top: 10px;
        font-size: 0.84rem;
        line-height: 1.3;
    }

    .nback-tool .progress-stack {
        gap: 7px;
        margin: 12px 0;
    }

    .nback-tool .progress-line {
        grid-template-columns: 44px minmax(0, 1fr);
        gap: 8px;
    }

    .nback-tool .progress-line > span {
        font-size: 0.66rem;
    }

    .nback-tool .play-area {
        display: flex;
        flex: 1;
        flex-direction: column;
        gap: 10px;
        min-height: 0;
    }

    .nback-tool .grid {
        width: min(100%, 56dvh);
        max-width: none;
        min-height: 0;
    }

    .nback-tool .cell {
        border-width: 1px;
    }

    .nback-tool .controls-panel {
        position: sticky;
        bottom: 0;
        z-index: 5;
        grid-template-columns: 1fr;
        gap: 8px;
        width: 100%;
        max-width: none;
        margin: auto 0 0;
        padding: 8px;
        border: 1px solid var(--nback-line);
        border-radius: 6px;
        background: color-mix(in srgb, var(--nback-panel) 94%, transparent);
        box-shadow: 0 -8px 24px rgba(0, 0, 0, 0.08);
    }

    .nback-tool .match-controls {
        order: 1;
        grid-template-columns: repeat(var(--stream-count, 1), minmax(0, 1fr));
        gap: 8px;
    }

    .nback-tool .match-button {
        grid-template-columns: 1fr;
        grid-template-rows: auto auto;
        justify-items: center;
        min-height: clamp(74px, 18dvw, 104px);
        padding: 10px 6px;
        text-align: center;
        font-size: clamp(0.78rem, 3.2dvw, 1rem);
        line-height: 1.15;
    }

    .nback-tool .match-button span {
        width: 38px;
        height: 32px;
        font-size: 0.92rem;
    }

    .nback-tool .match-button.is-selected {
        box-shadow: inset 0 0 0 2px var(--accent-color);
    }

    .nback-tool .stimulus-card {
        order: 0;
        min-height: 52px;
    }

    .nback-tool .stimulus-card[hidden] + .match-controls {
        order: 1;
    }

    .nback-tool .primary-actions {
        order: 2;
        grid-template-columns: 1fr 1fr;
        gap: 8px;
        min-width: 0;
    }

    .nback-tool .primary-actions button {
        min-height: 52px;
    }

    .nback-tool .load-grid {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    .nback-tool .training-options {
        grid-template-columns: 1fr;
        align-items: stretch;
    }

    .nback-tool .hotkeys {
        display: none;
    }
}

@media (max-width: 420px) {
    .nback-tool .match-button {
        min-height: 72px;
        font-size: 0.74rem;
    }

    .nback-tool .match-button span {
        width: 34px;
        height: 30px;
    }

    .nback-tool .primary-actions button {
        min-height: 48px;
    }
}