Some websites use different CSS styles to display on different systems. How can I use those style sheets to show this on another form factor? For instance, I would like to show how the screen style will look on a laptop.
You can modify your user agent (with an extension in Firefox, or with the
--user-agent= parameter when calling chromium). This can allow you to mimic your browser as Android's browser for example.
A pretty decent list of different user agents can be found here: http://www.useragentstring.com/pages/useragentstring.php