BrowserCheck

Add this script to your head section with jQuery included and check your environment (browser, device).

if($.browser.mobile) {
  alert("It's a mobile device!");
}

You can also add some classes to "html" tag:

environmentDetect(true, true, true);

Now you can depend your css on browser, devices and OS. Just try:

.idevice body {
  background : blue;
}