echarts折线图多条折线怎么每段显示不同的颜色?

option = {
    title: {
        text: '一天用电量分布',
        subtext: '纯属虚构'
    },
    tooltip: {
        trigger: 'axis',
        axisPointer: {
            type: 'cross'
        }
    },
    toolbox: {
        show: true,
        feature: {
            saveAsImage: {}
        }
    },
    xAxis: {
        type: 'category',
        boundaryGap: false,
        data: ['00:00', '01:15', '02:30', '03:45', '05:00', '06:15', '07:30', '08:45', '10:00', '11:15', '12:30', '13:45', '15:00', '16:15', '17:30', '18:45', '20:00', '21:15', '22:30', '23:45']
    },
    yAxis: {
        type: 'value',
        axisLabel: {
            formatter: '{value} W'
        },
        axisPointer: {
            snap: true
        }
    },
    visualMap: [{
        show: false,
        dimension: 0,
        seriesIndex:0,//第一部分数据
        pieces: [{
            lte: 6,
            color: 'orange'
        }, {
            gt: 6,
            lte: 8,
            color: 'red'
        }, {
            gt: 8,
            lte: 14,
            color: 'purple'
        }, {
            gt: 14,
            lte: 17,
            color: 'Chocolate'
        }, {
            gt: 17,
            color: 'pink'
        }]
    },
    {
        show: false,
        dimension: 0,
        seriesIndex:1,//第二部分数据
        pieces: [{
            lte: 3,
            color: 'blue'
        }, {
            gt: 3,
            lte: 8,
            color: 'black'
        }, {
            gt: 8,
            lte: 14,
            color: 'green'
        }, {
            gt: 14,
            lte: 17,
            color: 'grey'
        }, {
            gt: 17,
            color: 'DodgerBlue'
        }]
    }],
    series: [
        {
            name: '用电量',
            type: 'line',
            smooth: true,
            data: [300, 280, 250, 260, 270, 300, 550, 500, 400, 390, 380, 390, 400, 500, 600, 750, 800, 700, 600, 400]
        },
  
        {
            name: '费用',
            type: 'line',
            smooth: true,
            data: [200, 180, 150, 160, 170, 200, 450, 400, 300, 290, 280, 290, 300, 400, 400, 650, 700, 600, 450, 300]
        }
    ]
};