echarts4 主题切换

<!DOCTYPE html>
<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>Echarts Theme Switch</title>
    <script src="./js/jquery.min.js"></script>
    <script src="./js/echarts.js" type="text/javascript" charset="utf-8"></script>
    <script src = './js/theme/dark.js'></script>
    <script src = './js/theme/macarons.js'></script>
</head>
<body>
<select name="" id="sel">
    <option value="dark">dark</option>
    <option value="macarons">macarons</option>
</select>
<button id = 'clear'>clear</button>
<div id = 'zhuzhuangtu' style="height:399px;"></div>
</body>
</html>
<script>
    // 基于准备好的dom，初始化echarts实例
    var myChart = echarts.init(document.getElementById('zhuzhuangtu'),'dark');
    // 指定图表的配置项和数据
    var option = {
        title: {
            text: 'ECharts 入门示例'
        },
        tooltip: {},
        legend: {
            data:['销量']
        },
        xAxis: {
            data: ["衬衫","羊毛衫","雪纺衫","裤子","高跟鞋","袜子"]
        },
        grid:{
            show:true,
            backgroundColor:'black'
        },
        yAxis: {},
        series: [{
            name: '销量',
            type: 'bar',
            data: [5, 20, 36, 10, 10, 20]
        }]
    };

    // 使用刚指定的配置项和数据显示图表。
    myChart.setOption(option);
    $('#sel').change(function(){
        myChart.dispose();
        let Theme = $(this).val();
        // 基于准备好的dom，初始化echarts实例
        myChart = echarts.init(document.getElementById('zhuzhuangtu'),Theme);
        // 使用刚指定的配置项和数据显示图表。
        myChart.setOption(option);
    });
</script>
主题什么的在线资源没找到，自行下载吧