<style>
  body {
    margin: 0;
    overflow: hidden;
  }

    .canvas-wrapper {
        position: relative;
    }
    .canvas-wrapper canvas{
        position: absolute;
        top: 0;
        left: 0;
    }
    .canvas-wrapper div{
        position: absolute;
        left: 0;
        top: 0;
        max-width: 500px; /* 最大幅 */
        min-width: 300px; /* 最小幅 */
        width : 40%;
        height: 280px;
    }
    
</style>