tree 节点颜色设置问题

描述:当前是关于Echarts图表中的 树图 示例。
 
            var data = {
    "name": "flare",
    "children": [{
            "name": "flex",
            itemStyle: {
                normal: {
                    borderColor: '#c23531'
                }
            },
            "children": [{
                "name": "FlareVis",
                "value": 4116
            }]
        },
        {
            "name": "scale",
            

            "children": [{
                    "name": "IScaleMap",
                    "value": 2105
                },
                {
                    "name": "LinearScale",
                    "value": 1316
                },
                {
                    "name": "LogScale",
                    "value": 3151
                },
                {
                    "name": "OrdinalScale",
                    "value": 3770
                },
                {
                    "name": "QuantileScale",
                    "value": 2435
                },
                {
                    "name": "QuantitativeScale",
                    "value": 4839
                },
                {
                    "name": "RootScale",
                    "value": 1756
                },
                {
                    "name": "Scale",
                    "value": 4268
                },
                {
                    "name": "ScaleType",
                    "value": 1821
                },
                {
                    "name": "TimeScale",
                    "value": 5833
                }
            ]
        },
        {
            "name": "display",
            "children": [{
                "name": "DirtySprite",
                "value": 8833,
                itemStyle: {
                borderColor: "red"
        },
            }]
        }
    ]
};

myChart.hideLoading();

myChart.setOption(option = {
    tooltip: {
        trigger: 'item',
        triggerOn: 'mousemove'
    },
    legend: {
        top: '2%',
        left: '3%',
        orient: 'vertical',
        data: [{
            name: 'tree1',
            icon: 'rectangle'
        }],
        borderColor: '#c23531'
    },
    series: [{
        type: 'tree',

        //  initialTreeDepth: -1,

        name: 'tree1',

        data: [data],

        top: '5%',
        left: '7%',
        bottom: '2%',
        right: '14%',

        symbolSize: 10,

        label: {
            normal: {
                position: 'left',
                verticalAlign: 'middle',
                align: 'right',
                color: 'black'
            }
        },

        leaves: {
            label: {
                normal: {
                    position: 'right',
                    verticalAlign: 'middle',
                    align: 'left',
                }
            },

        },


        itemStyle: {
            normal: {

                borderColor: "green"
            }
        },
        expandAndCollapse: true,

        animationDuration: 550,
        animationDurationUpdate: 750

    }]
});