but because we don't create them ourselves, we can't guarantee your satisfaction. Warning Like extensions (see Chapter 20), most themes are created not by the core Firefox team but by volunteer developers during their spare time. Therefore, some themes might not work properly, and others might have undesirable side effects, such as slowing down Firefox. Some, of course, might just be ugly! Mozilla Update organizes themes into categories, as shown in Figure 17-1. Some of these categories indicate theme content, such as Nature and Sports, and others indicate the approximate size of a theme's buttons, like Compact and Large. Click a category to see its description and a list of its themes. Most themes offer a small preview that gives you a taste of what to expect. Figure 17-1: Mozilla Update organizes hundreds of themes into categories such as Nature, Retro, and Sports. I include a sampling of my favorite themes in Figures 17-2 and 17-3. If you're feeling overwhelmed, try the Popular or Top Rated categories to see what other Firefox users enjoy. You can also click a particular theme to read reviews from people who tried it, as shown in Figure 17-1. Figure 17-2: A selection of my favorite themes. (They're even better in color!) Figure 17-3: The Scribblies Brite theme (Category: Miscellaneous). Tip Mozilla Update isn't the only place to find themes. Many designers offer their themes on their own home pages, and even Hollywood is getting into the act. For example, on the Warner Bros' Web site, the Batman Begins movie offered a Batman theme. Search Google (http://www.google.com) for Firefox Themes, and be sure to regularly check the Newest category of Mozilla Update. When you find an interesting theme, don't spend a lot of time deciding whether to try it. You can install and remove themes so quickly that it's worth your while to experiment. First, however, make sure you read the following section on theme compatibility.           Ensuring Theme Compatibility Each theme is designed to work with a particular version of Firefox or a range of versions. This seems strange at first, but makes more sense when you consider that each version of Firefox adds some new features. A designer has trouble theming a feature that hasn't been invented yet, just as a painter can't paint a room that hasn't been built. Firefox prevents you from installing an incompatible theme, but you can save yourself some trouble by ensuring a theme's compatibility before installing it. Mozilla Update provides a theme's compatibility information below its Install link in the form of a range of Firefox versions that it supports (for example, Firefox 1.0-1.5). If a theme supports only one version, the endpoints of the range are identical (for example, Firefox 1.0-1.0). Make sure that your version of Firefox, which you can find out by choosing Help About Mozilla Firefox), falls within the listed range. REMEMBER Even if you use a theme that's compatible with your version of Firefox, problems can occur if you're using an extension that changes or extends the Firefox interface. (See Chapter 20 for information about extensions.) Firefox does the best it can to apply your theme to installed extensions, but