body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 20px;
    background-color: #f5f5f5;
}

#chart-container {
    width: 100%;
    height: 800px;
    position: relative;
}

.node {
    fill: #ccc;
    stroke: #fff;
    stroke-width: 2px;
}

.node.goal {
    fill: #8BC34A; /* 绿色背景，对应顶部框 */
}

.node.primary {
    fill: #000;
    color: white;
}

.node.secondary {
    fill: #f0f0f0;
}

.node.grey {
    fill: #ccc;
}

text {
    font-size: 12px;
    text-anchor: middle;
    dominant-baseline: middle;
    fill: #333;
}

.node.primary text {
    fill: white;
}

.link {
    fill: none;
    stroke: #666;
    stroke-width: 1.5px;
    marker-end: url(#arrowhead);
}

.number-circle {
    font-size: 24px;
    font-weight: bold;
    fill: white;
}