:root {
    --dc-primary: #26a69a;
    --dc-primary-dark: #087f74;
    --dc-primary-soft: #e0f2f1;
    --dc-accent: #ffb300;
    --dc-ink: #263238;
    --dc-muted: #607d8b;
    --dc-border: #cfd8dc;
    --dc-surface: #f7faf9;
}

#divide-conquer-page p {
    line-height: 1.65;
}

#divide-conquer-page .browser-default {
    padding-left: 1.5rem;
}

.dc-concept-grid,
.dc-exercise-grid,
.dc-master-cases {
    display: grid;
    gap: 1rem;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    margin: 1.5rem 0;
}

.dc-concept-card,
.dc-exercise,
.dc-master-cases article {
    border: 1px solid var(--dc-border);
    border-radius: 0.65rem;
    padding: 1rem;
}

.dc-concept-card {
    background: var(--dc-surface);
    position: relative;
}

.dc-concept-card h6 {
    color: var(--dc-primary-dark);
    font-weight: 600;
    margin: 0.35rem 0 0.5rem;
}

.dc-concept-number {
    align-items: center;
    background: var(--dc-primary);
    border-radius: 50%;
    color: white;
    display: inline-flex;
    font-weight: 700;
    height: 2rem;
    justify-content: center;
    width: 2rem;
}

.dc-demo {
    background: linear-gradient(145deg, #ffffff, var(--dc-surface));
    border: 1px solid var(--dc-border);
    border-radius: 0.75rem;
    box-shadow: 0 0.25rem 0.9rem rgba(38, 50, 56, 0.08);
    margin: 1.5rem 0 0.5rem;
    overflow: hidden;
    padding: 1.25rem;
}

.dc-demo-heading {
    align-items: flex-start;
    display: flex;
    gap: 1rem;
    justify-content: space-between;
    margin-bottom: 1rem;
}

.dc-demo-heading h6 {
    font-weight: 600;
    margin: 0 0 0.35rem;
}

.dc-demo-status {
    color: var(--dc-muted);
    margin: 0 !important;
    min-height: 1.5rem;
}

.dc-controls {
    align-items: center;
    display: flex;
    flex-wrap: wrap;
    gap: 0.55rem;
    justify-content: center;
    margin-top: 1rem;
}

.dc-controls .btn-small,
.dc-demo-heading .btn-small,
.dc-master-presets .btn-small {
    align-items: center;
    display: inline-flex;
    justify-content: center;
}

.dc-play.is-playing {
    background-color: var(--dc-accent) !important;
}

.dc-phase-track {
    display: grid;
    gap: 0.4rem;
    grid-template-columns: repeat(4, 1fr);
    margin-bottom: 1.25rem;
}

.dc-phase-track button {
    background: white;
    border: 1px solid var(--dc-border);
    border-radius: 0.35rem;
    color: var(--dc-muted);
    cursor: pointer;
    min-height: 2.5rem;
    padding: 0.4rem;
}

.dc-phase-track button.is-active {
    background: var(--dc-primary);
    border-color: var(--dc-primary);
    color: white;
    font-weight: 600;
}

.dc-array-stage,
.dc-merge-stage {
    align-items: center;
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    justify-content: center;
    min-height: 7.5rem;
}

.dc-array-group {
    align-items: center;
    background: white;
    border: 2px solid var(--dc-primary);
    border-radius: 0.5rem;
    display: inline-flex;
    gap: 0.25rem;
    padding: 0.45rem;
    position: relative;
}

.dc-array-group + .dc-array-group::before {
    color: var(--dc-muted);
    content: "+";
    font-size: 1.4rem;
    left: -0.8rem;
    position: absolute;
}

.dc-number {
    align-items: center;
    background: var(--dc-primary-soft);
    border-radius: 0.3rem;
    color: var(--dc-ink);
    display: inline-flex;
    font-family: monospace;
    font-size: 1rem;
    font-weight: 700;
    height: 2.4rem;
    justify-content: center;
    min-width: 2.4rem;
    padding: 0 0.35rem;
}

.dc-formula {
    background: var(--dc-primary-soft);
    border-left: 4px solid var(--dc-primary);
    border-radius: 0.25rem;
    font-size: 1.05rem;
    margin: 1rem 0;
    overflow-x: auto;
    padding: 0.9rem 1rem;
    text-align: center;
}

.dc-range-label {
    color: var(--dc-ink);
    min-width: 11rem;
}

.dc-range-label output {
    color: var(--dc-primary-dark);
    font-weight: 700;
}

.dc-range-label input[type="range"] {
    margin: 0.4rem 0 0;
}

.dc-stairs {
    align-items: flex-end;
    display: flex;
    gap: 0.2rem;
    justify-content: center;
    min-height: 12rem;
    overflow-x: auto;
    padding: 1rem 0.5rem 0;
}

.dc-stair {
    align-items: flex-start;
    background: var(--dc-primary-soft);
    border: 2px solid var(--dc-primary);
    border-radius: 0.25rem 0.25rem 0 0;
    display: flex;
    flex: 0 0 3rem;
    justify-content: center;
    min-height: 2rem;
    padding-top: 0.3rem;
    position: relative;
    transition: background-color 180ms ease, transform 180ms ease;
}

.dc-stair.is-current {
    background: #fff8e1;
    border-color: var(--dc-accent);
    transform: translateY(-0.3rem);
}

.dc-stair.is-reached::after {
    color: var(--dc-primary-dark);
    content: "●";
    font-size: 0.7rem;
    position: absolute;
    top: -1.1rem;
}

.dc-recurrence-strip {
    display: flex;
    flex-wrap: wrap;
    gap: 0.45rem;
    justify-content: center;
    margin-top: 1rem;
    min-height: 3rem;
}

.dc-recurrence-cell {
    align-items: center;
    background: white;
    border: 1px solid var(--dc-border);
    border-radius: 0.35rem;
    display: inline-flex;
    flex-direction: column;
    min-width: 4rem;
    padding: 0.35rem 0.5rem;
}

.dc-recurrence-cell.is-active {
    border-color: var(--dc-accent);
    box-shadow: 0 0 0 2px rgba(255, 179, 0, 0.2);
}

.dc-recurrence-cell small {
    color: var(--dc-muted);
}

.dc-result {
    background: var(--dc-primary-soft);
    border-radius: 0.4rem;
    color: var(--dc-primary-dark);
    font-weight: 600;
    margin: 1rem 0 0 !important;
    min-height: 2.9rem;
    padding: 0.7rem 0.9rem;
    text-align: center;
}

.dc-size-inputs,
.dc-master-inputs {
    align-items: flex-end;
    display: flex;
    flex-wrap: wrap;
    gap: 0.8rem;
}

.dc-size-inputs label,
.dc-master-inputs label {
    color: var(--dc-muted);
    width: 5rem;
}

.dc-size-inputs input,
.dc-master-inputs input {
    height: 2.2rem !important;
    margin: 0 !important;
    text-align: center;
}

.dc-grid-wrap {
    margin: 1rem auto;
    max-width: 36rem;
    position: relative;
}

.dc-path-grid {
    --dc-grid-columns: 5;
    display: grid;
    gap: 0.3rem;
    grid-template-columns: repeat(var(--dc-grid-columns), minmax(2.5rem, 1fr));
}

.dc-path-cell {
    align-items: center;
    aspect-ratio: 1;
    background: white;
    border: 1px solid var(--dc-border);
    border-radius: 0.3rem;
    color: var(--dc-muted);
    display: flex;
    font-family: monospace;
    font-size: 1rem;
    justify-content: center;
    transition: background-color 160ms ease, border-color 160ms ease;
}

.dc-path-cell.is-filled {
    background: var(--dc-primary-soft);
    border-color: var(--dc-primary);
    color: var(--dc-ink);
    font-weight: 700;
}

.dc-path-cell.is-source {
    background: #fff8e1;
    border-color: var(--dc-accent);
}

.dc-path-cell.is-current {
    box-shadow: 0 0 0 3px rgba(255, 179, 0, 0.3);
}

.dc-grid-start,
.dc-grid-finish {
    background: var(--dc-ink);
    border-radius: 0.25rem;
    color: white;
    font-size: 0.72rem;
    padding: 0.2rem 0.35rem;
    position: absolute;
    z-index: 1;
}

.dc-grid-start {
    left: -0.4rem;
    top: -0.75rem;
}

.dc-grid-finish {
    bottom: -0.75rem;
    right: -0.4rem;
}

.dc-two-column {
    align-items: start;
    display: grid;
    gap: 1.25rem;
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
}

.dc-two-column pre {
    margin: 0.5rem 0;
}

.dc-merge-stage {
    align-content: center;
    flex-direction: row;
}

.dc-master-cases article {
    align-items: center;
    background: var(--dc-surface);
    display: flex;
    flex-direction: column;
    text-align: center;
}

.dc-master-cases span {
    color: var(--dc-primary-dark);
}

.dc-master-cases b {
    font-size: 1.1rem;
    margin: 0.6rem 0;
}

.dc-master-cases p {
    color: var(--dc-muted);
    margin: 0;
}

.dc-master-presets {
    display: flex;
    flex-wrap: wrap;
    gap: 0.45rem;
    justify-content: flex-end;
}

.dc-master-calculation {
    color: var(--dc-ink);
    margin: 1rem 0;
    text-align: center;
}

.dc-recursion-tree {
    display: flex;
    flex-direction: column;
    gap: 0.8rem;
    min-height: 9rem;
    overflow-x: auto;
    padding: 0.5rem;
}

.dc-tree-level {
    align-items: center;
    display: flex;
    gap: 0.35rem;
    justify-content: center;
    min-width: max-content;
}

.dc-tree-level-label {
    color: var(--dc-muted);
    font-size: 0.72rem;
    margin-right: 0.25rem;
    min-width: 3.5rem;
}

.dc-tree-node {
    align-items: center;
    background: var(--dc-primary-soft);
    border: 1px solid var(--dc-primary);
    border-radius: 999px;
    display: inline-flex;
    font-family: monospace;
    font-size: 0.78rem;
    justify-content: center;
    min-height: 2rem;
    min-width: 3.8rem;
    padding: 0.2rem 0.5rem;
}

.dc-tree-ellipsis {
    color: var(--dc-muted);
    font-weight: 700;
}

.dc-exercise-grid {
    align-items: stretch;
    grid-template-columns: repeat(2, minmax(0, 1fr));
}

.dc-exercise {
    background: var(--dc-surface);
    display: flex;
    flex-direction: column;
}

.dc-exercise h6 {
    color: var(--dc-primary-dark);
    font-weight: 600;
}

#dc-code-recurrence-exercise {
    grid-column: 1 / -1;
}

#dc-code-recurrence-exercise pre {
    margin: 0.5rem 0 1rem;
    max-height: 24rem;
    overflow: auto;
}

.dc-exercise-question {
    min-height: 3.2rem;
}

.dc-answer-grid {
    display: grid;
    gap: 0.5rem;
    grid-template-columns: 1fr;
    margin: 0.75rem 0;
}

.dc-answer-grid button {
    background: white;
    border: 1px solid var(--dc-border);
    border-radius: 0.35rem;
    color: var(--dc-ink);
    cursor: pointer;
    min-height: 2.8rem;
    padding: 0.55rem;
    text-align: center;
    transition: background-color 120ms ease, border-color 120ms ease;
}

.dc-answer-grid button:hover,
.dc-answer-grid button:focus-visible {
    border-color: var(--dc-primary);
    outline: none;
}

.dc-answer-grid button.is-correct {
    background: #e8f5e9;
    border-color: #2e7d32;
    color: #1b5e20;
}

.dc-answer-grid button.is-incorrect {
    background: #ffebee;
    border-color: #c62828;
    color: #b71c1c;
}

.dc-feedback {
    font-weight: 600;
    margin-top: auto !important;
    min-height: 1.6rem;
}

.dc-feedback.is-correct {
    color: #2e7d32;
}

.dc-feedback.is-incorrect {
    color: #c62828;
}

@media screen and (max-width: 900px) {
    .dc-concept-grid,
    .dc-exercise-grid,
    .dc-master-cases,
    .dc-two-column {
        grid-template-columns: 1fr;
    }

    .dc-demo-heading {
        align-items: stretch;
        flex-direction: column;
    }

    .dc-master-presets {
        justify-content: flex-start;
    }
}

@media screen and (max-width: 600px) {
    .dc-demo {
        padding: 0.85rem;
    }

    .dc-phase-track {
        grid-template-columns: repeat(2, 1fr);
    }

    .dc-number {
        height: 2rem;
        min-width: 2rem;
    }

    .dc-stair {
        flex-basis: 2.4rem;
    }

    .dc-size-inputs,
    .dc-master-inputs {
        width: 100%;
    }
}

@media (prefers-reduced-motion: reduce) {
    #divide-conquer-page *,
    #divide-conquer-page *::before,
    #divide-conquer-page *::after {
        scroll-behavior: auto !important;
        transition-duration: 0.001ms !important;
    }
}