Why does IE11 render the page incorrectly?

Question

css

Hello. If you open the site (normal static html + css) directly through IE11, then everything looks fine;

if through the server, then IE11 shows like this

in chrome, everything works correctly, in which direction should I dig?

Answer 1

Insert this tag in head
and you will be happy!

Answer 2

Because it doesn't know the main tag.
Add to CSS:
main { display: block; }