Crossbrowser compatibility in IE < 11?

Question

css

There is a site .
When you click on the image, all unnecessary goes down and only the arrows remain - this is the standard behavior, you can see it in modern browsers (eg in chrome). But in IE below version 11, all these zones are not clickable.
Why is IE below version 11 behaving so ugly?
P/S.
You can not search in scripts. Here, even the cursor pointer does not work, which means that the problem is at the html / css level of the
GitHub site .

Answer 1

If the zones are not clickable, then, apparently, these zones lie in the layers below. Try playing around with the z-index. Just don't forget to set position: relative, for example, otherwise the z-index won't work.

Answer 2

I would make a popup for ie "You are using non-Internet based software, please download a browser."
In edge, by the way, everything works.
Check if you have scripts disabled in ie js. Somehow I lost a day because of this.