Soft Rejected FOUC issue

Hi everyone,
We got a soft rejection on this Angular 12 template.

NetStorm - Angular 12 NFT Marketplace

Here are the reviewer comments below:

Please fix this FOUC* Untitled.mp4 - Droplr

Please anyone suggest how to fix this issue.

Thanks

You already have an answer on Wikipedia link. Have you read that?

With the advent of JavaScript libraries such as jQuery that can be employed to further define and apply the styling of a web page, FOUC has also become more prominent. In an attempt to avoid unstyled content, front-end developers may choose to hide all content until it is fully loaded, at which point a load event handler is triggered and the content appears, though an interruption of loading might leave behind a blank page, to which unstyled content would be preferable.

In short - create a preloader / loading animation (or just blank / white screen) until is all loaded.