.container {
            max-width: 1200px;
            margin: 0 auto;
            padding: 20px;
        }

        .controls {
            display: flex;
            gap: 20px;
            margin-bottom: 20px;
            align-items: center;
        }

        select {
            padding: 8px;
            border: 1px solid #dee2e6;
            border-radius: 4px;
            font-size: 14px;
            min-width: 150px;
        }

        .chart-container {
            position: relative;
            width: 100%;
            height: 600px;
            background: white;
            border-radius: 8px;
            box-shadow: 0 2px 4px rgba(0,0,0,0.1);
        }

        .node {
            stroke: #fff;
            stroke-width: 1px;
        }

        .node-label {
            font-size: 15px;
            font-family: sans-serif;
            pointer-events: none;
            fill: white;
        }

        .value-label {
            font-size: 14px;
            fill: white;
            opacity: 0.8;
        }

        .tooltip {
    position: absolute;
    padding: 8px;
    background: rgba(0, 0, 0, 0.8);
    color: white;
    border-radius: 4px;
    font-size: 12px;
    pointer-events: none;
    display: none;
    transform: translate(-100%, -400%); /* Center horizontally and place above cursor */
    margin-top: -4px; /* Additional offset */
}