Theme (computing)

In computing, a theme is a preset package containing graphical appearance details. A theme usually comprises a set of shapes and colors for the graphical control elements, the window decoration and the window. Themes are used to customize the look and feel of a piece of computer software or of an operating system.

Themes are often used to change the look and feel of a wide range of things at once, which makes them much less granular than allowing the user to set each option individually. For example, you might want the window-borders from a particular theme, but installing it would also alter your desktop background.

One method for dealing with this is to allow the user to select which parts of the theme they want to load; for example in Windows 98, you could load the background and screensaver from a theme, but leave your icons and sounds untouched.

Firefox and Google Chrome either support or supported a form of theme. Firefox (and its sibling Thunderbird) supports themes either through lightweight themes (formerly Personas) or complete themes. While lightweight themes are simply background images for toolbar Firefox toolbars, complete themes have more power to modify Firefox's appearance. Google Chrome version 3.0 or later allows themes to alter the appearance of the browser.Internet Explorer 5 and its immediate successor allowed the background picture of their toolbars to be customized.

Other software such as Midnight Commander and Notepad++ support themes.

...
Wikipedia