You might wish to check a site that give you browser versions for when different features were implemented. IE8 has very poor support for HTML5 and CSS3.
So the search you need to do is HTML/CSS compatibility and browser versions.
For example:
CSS3 Reference[
^] and other locations within this website
or test your browser's compatibility here:
HTML5test - How well does your browser support HTML5?[
^] and open the link within various browsers yo may have.