Firefox (45% of JR readers use it) has a plugin architecture that allows easy customization of the header and footer areas using the Firefox Persona plugin. You can also customize the appearance of any web site viewed in Firefox using the Stylish add-on that we’ll use in part 2 to make a transparent background for our Twitter home page. There are also many skins and themes for Firefox that we’ll explore in part 3. The screenshot shows the semi-transparent theme diamond and you can see the Jack Rebel header logo bleeding through in the title bar from the window behind.
Here’s a Firefox Persona with Yosemite’s Half Dome (click to enlarge):