::v-deep usage as a combinator has been deprecated

:deep {
        .el-form-item__label {
            color: #fff;
        }
}

提示

[@vue/compiler-sfc] ::v-deep usage as a combinator has been deprecated. Use :deep() instead.

正确的使用是：

:deep() {
        .el-form-item__label {
            color: #fff;
        }
}