I converted my website to HTML 5 and most of my browser issues are fixed except for !E and a few others like Ubuntu.
IE 10 looks OK. On the others it is the horizontal nav that is the problem. The navbar text is appearing over the left nav and the social media icons disappeared in some cases and the others are showing below the horizontal navbar on the right. For some reason they also have a blue border.
I added the custom Modernizr script with Yepnope to the header to help. Being a newbie, I do not know how to use, but it sure seemed like a good idea! Anyway, I could use some pointers on how to fix this problem.
Then you do need to begin learning - and we've all been there so don't worry about it. However, putting a ready-made script on a web page without understanding it to some degree is setting yourself up for a loss and major frustration.
I'd say start by making sure your mark-up is valid: