.chart-container {
        background: var(--bg-card);
        border-radius: 20px;
        box-shadow: 0 8px 32px rgba(0, 0, 0, 0.05);
        border: 1px solid var(--border-color);
        padding: 1.5rem;
        position: relative;
        margin-bottom: 2rem;
        transition: transform 0.3s ease;
    }

    .chart-container.premium-dark {
        background: #0f172a;
        border: 1px solid rgba(255, 255, 255, 0.05);
        color: #f8fafc;
    }

    .chart-container.premium-dark .chart-title {
        color: #f8fafc;
    }

    .chart-header {
        display: flex;
        justify-content: space-between;
        align-items: center;
        margin-bottom: 1.5rem;
        padding-bottom: 1rem;
        border-bottom: 1px solid rgba(var(--color-primary-rgb), 0.1);
    }

    .chart-title {
        font-family: 'Outfit', sans-serif;
        font-size: 1.25rem;
        font-weight: 700;
        letter-spacing: -0.02em;
        color: var(--text-primary);
        margin: 0;
    }

    .loader-overlay {
        position: absolute;
        top: 0;
        left: 0;
        right: 0;
        bottom: 0;
        display: flex;
        flex-direction: column;
        justify-content: center;
        align-items: center;
        background: rgba(15, 23, 42, 0.8);
        backdrop-filter: blur(8px);
        z-index: 100;
        border-radius: 20px;
        color: white;
    }

    .spinner {
        width: 48px;
        height: 48px;
        border: 3px solid rgba(255, 255, 255, 0.1);
        border-top: 3px solid #6366f1;
        border-radius: 50%;
        animation: spin 1s cubic-bezier(0.4, 0, 0.2, 1) infinite;
        margin-bottom: 1rem;
    }

    @keyframes spin {
        to {
            transform: rotate(360deg);
        }
    }

    /* Chart containers get a min-height while data loads */
    .chart-container:not(.premium-dark) .plotly-chart-empty,
    .d3-treemap-wrap:empty {
        min-height: 80px;
    }

    .heatmap-hero {
        background: linear-gradient(135deg, #1e3c72 0%, #2a5298 100%);
        padding: 3rem 2.5rem;
        border-radius: 24px;
        position: relative;
        overflow: hidden;
        box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    }

    .heatmap-hero::after {
        content: '';
        position: absolute;
        top: -50%;
        right: -20%;
        width: 80%;
        height: 200%;
        background: radial-gradient(circle, rgba(255, 255, 255, 0.05) 0%, transparent 70%);
        transform: rotate(-15deg);
        pointer-events: none;
    }

    .divider-v {
        width: 1px;
        height: 40px;
        background: rgba(255, 255, 255, 0.1);
    }

    .hero-stat-label {
        color: rgba(255, 255, 255, 0.5);
        text-transform: uppercase;
        font-weight: 700;
        font-size: 0.65rem;
        letter-spacing: 1px;
    }

    .tier-selector-container {
        display: flex;
        justify-content: center;
        margin-bottom: 2rem;
        gap: 0.5rem;
        flex-wrap: wrap;
    }

    .tier-btn {
        background: var(--bg-card);
        border: 1px solid var(--border-color);
        color: var(--text-muted);
        padding: 0.6rem 1.25rem;
        border-radius: 50px;
        font-weight: 600;
        font-size: 0.85rem;
        transition: all 0.2s ease;
        cursor: pointer;
        display: flex;
        align-items: center;
        gap: 0.5rem;
    }

    .tier-btn:hover {
        border-color: var(--color-primary);
        color: var(--color-primary);
        background: rgba(var(--color-primary-rgb), 0.05);
    }

    .tier-btn.active {
        background: var(--color-primary);
        color: white;
        border-color: var(--color-primary);
        box-shadow: 0 4px 12px rgba(var(--color-primary-rgb), 0.3);
    }

    .tier-icon {
        font-size: 1rem;
    }

    /* Treemap containers */
    .d3-treemap-wrap {
        overflow: hidden;
        border-radius: 8px;
    }