CSS doesn't works properly with IE sometimes

[aviaryan]

For example take a look at this page - https://rawgit.com/aviaryan/Clipjump/master/chm_files/docs/channels.html
First open it with a modern browser like Chrome/Firefox and then try opening it with IE.
From what I see , IE 9 fails to correctly load the keyscss and makes the key such that it is visible only on selection.

This doesn't happen always, see this HTML file for example.

[aviaryan]

Update: I have changed the HTML files to include another CSS for kbd. The links now don't use keyscss. I will post an example demonstrating the problem soon