/* Warm ivory reading theme — the single source of truth for every colour and font.
 * Was duplicated verbatim in all 13 HTML files; now linked by each of them.
 * Never hardcode a colour anywhere else. See docs/AGENTS.md §4. */
:root {
    /* Surfaces */
    --bg-color:       #FAF6F0;
    --bg-sunk:        #F2ECE2;
    --card-bg:        #FFFCF7;
    --card-bg-alt:    #F5EFE6;
    --panel-bg:       #FBF6EE;
    --sidebar-bg:     #FFFCF7;

    /* Lines */
    --border-color:   #E6DBCB;
    --border-strong:  #D6C6AF;
    --border-subtle:  #EFE7DA;

    /* Ink */
    --text-primary:   #2B2622;
    --text-body:      #3A342E;
    --text-secondary: #6E635A;
    --text-muted:     #756C63;
    --text-ghost:     #918880;
    --text-on-accent: #FFFDF9;
    --ink-rgb:        43, 38, 34;

    /* Accents (retuned for a light ground) */
    --accent-cyan:    #0E7490;
    --accent-purple:  #6D45A8;
    --accent-green:   #3C7549;
    --accent-orange:  #AA4E07;
    --accent-pink:    #B03A62;
    --accent-blue:    #1D5FA8;
    --accent-red:     #B3261E;

    /* Accent tints */
    --tint-cyan:      #E4F0F3;
    --tint-purple:    #EFE9F7;
    --tint-green:     #E8F1E9;
    --tint-orange:    #FBEEDC;
    --tint-pink:      #FAE8EE;
    --tint-neutral:   #F1E9DD;

    /* Depth */
    --shadow:         0 1px 2px rgba(90,70,45,.05), 0 6px 20px rgba(90,70,45,.07);
    --shadow-soft:    0 1px 3px rgba(90,70,45,.06);
    --ring:           0 0 0 3px rgba(14,116,144,.14);
    --glow:           var(--ring);

    /* Type */
    --font-heading:   'Outfit', 'Noto Sans Bengali', sans-serif;
    --font-body:      'Noto Sans Bengali', system-ui, sans-serif;
    --font-main:      var(--font-body);
}

/* ============================================================================
 * Deep Dive / Optional Interactive Visualizer Card Styles
 * ==========================================================================*/
.deepdive-card {
    border: 1px solid var(--border-color);
    transition: border-color 0.25s ease, box-shadow 0.25s ease;
    position: relative;
}

.deepdive-card.is-expanded {
    border-color: var(--accent-cyan);
    box-shadow: var(--shadow);
}

.deepdive-badge-bar {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 0.75rem;
}

.deepdive-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.35rem;
    font-size: 0.78rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.04em;
    padding: 0.25rem 0.65rem;
    border-radius: 9999px;
    background: var(--tint-cyan);
    color: var(--accent-cyan);
    border: 1px solid rgba(14, 116, 144, 0.25);
}

.deepdive-teaser {
    color: var(--text-secondary);
    font-size: 0.96rem;
    line-height: 1.6;
    margin-bottom: 1rem;
}

.deepdive-actions {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.deepdive-toggle-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    background: var(--tint-cyan);
    color: var(--accent-cyan);
    border: 1px solid rgba(14, 116, 144, 0.35);
    padding: 0.65rem 1.25rem;
    border-radius: 8px;
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
    font-family: inherit;
    user-select: none;
}

.deepdive-toggle-btn:hover {
    background: var(--accent-cyan);
    color: var(--text-on-accent);
    transform: translateY(-1px);
    box-shadow: var(--shadow-soft);
}

.deepdive-toggle-btn .toggle-icon {
    display: inline-block;
    transition: transform 0.25s ease;
    font-size: 0.85em;
}

.deepdive-card.is-expanded .deepdive-toggle-btn .toggle-icon {
    transform: rotate(180deg);
}

.deepdive-content {
    display: none;
    opacity: 0;
    margin-top: 0;
    transition: opacity 0.3s ease;
}

.deepdive-card.is-expanded .deepdive-content {
    display: block;
    opacity: 1;
    margin-top: 1.25rem;
    padding-top: 1.25rem;
    border-top: 1px dashed var(--border-color);
    animation: fadeInDeepDive 0.35s ease-out forwards;
}

@keyframes fadeInDeepDive {
    from {
        opacity: 0;
        transform: translateY(-6px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.deepdive-footer {
    display: flex;
    justify-content: center;
    margin-top: 1.5rem;
    padding-top: 1rem;
    border-top: 1px dashed var(--border-subtle);
}

.deepdive-footer-btn {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    background: var(--card-bg-alt);
    color: var(--text-secondary);
    border: 1px solid var(--border-color);
    padding: 0.45rem 1.1rem;
    border-radius: 6px;
    font-size: 0.88rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
    font-family: inherit;
}

.deepdive-footer-btn:hover {
    background: var(--bg-sunk);
    color: var(--text-primary);
    border-color: var(--border-strong);
}

/* Ensure [hidden] attribute works reliably across all elements, overriding display:flex/grid */
[hidden] {
    display: none !important;
}