I and sending you the js file which can check the browser name and version ..
In your page header just put a link like this
link href="" rel="stylesheet" type="text/css" id="cssname" />
Just call the script in header,
'cssname','<here give the css name for that file>');
and for each browser you have to create a different css with same name, and put it inside css folder of your webcontent.
I have check the version also, you can avoid that if not required.
detectbrowser.js 7.4 K