<el-dialog class="dialogClass">

.dialogClass {
  .el-dialog {
    .el-dialog__body {
      //border-top: 1px solid #dcdfe6;
      //border-bottom: 1px solid #dcdfe6;
      max-height: 500px !important;
      min-height: 100px;
      overflow-y: hidden;
    }
  }
}