Vue + element, SCSS plus / deep / style does not work

Vue + Element, SCSS plus /deep/ style does not work
For example: To adjust the style of. El-collapse-item__header

/deep/.el-collapse-item__header{
	 background-color: red;
}

Don’t take effect.
Replace /deep/ with ::v-deep

::v-deep .el-collapse-item__header{
	background-color: red;
}

Feel free to set the style you want ^ _^

Read More: