The sitemap appears for 1-2 seconds. when loading the site, how to fix it?

Question

css

It all started after I made the site header (picture, buttons). And now before loading the page, the sitemap and buttons appear for 1-2 seconds. What could be the problem? here is the site ocdod174.ddns.net
ps when I completely remove the header, I leave only me, everything loads with a bang.

Answer 1

It's called FOUC - Flash Of Unstyled Content. It happens because you have invalid and crooked HTML, your menu is displayed in HEAD (where it cannot be, by definition, only in BODY), and before CSS. Hence the problem - first the browser spits out the HTML markup, and then it realizes that there are more styles, takes them and redraws the page.
And yes, feel free to put all these counters and other shit scripts in the footer, and even better asynchronously and with a delay. They shouldn't be done before.

Answer 2

1. Do not follow the bad practice of loading js at the very end
or
2. Hang a preloader on the site

Answer 3

This is not a map, but the menu is loaded crookedly at first. It's not generated by a script?

Answer 4

What are the meta tags in the body?