如何给el-dialog添加背景图

HTML代码

<el-dialog 
  class="welfare-dialog" 
  :visible.sync="dialogVisible" 
  width="50%" 
  :show-close="false" 
  :before-close="handleClose"
>
  <div></div>
</el-dialog>

CSS代码

.welfare-dialog {
    ::v-deep {
      .el-dialog {
        border: 0;
        box-shadow: none;
        background: rgb(255, 255, 255, 0);
      }
      .el-dialog__header {
        display: none;
      }
      .el-dialog__body {
        padding: 0;
        position: relative;
        & > div {
          // width: 600px;
          position: relative;
          top: -50px;
          height: 665px;
          background-size: 100% 100%;
          background-image: url(../public/img/底框.png);
          background-repeat: no-repeat;
        }
      }
    }
  }