Cascading Style Sheets

Most web applications delegate to Cascading Style Sheets (CSS) the stylistic details of the page – fonts, colors, margins, borders and alignment. This helps the remaining HTML to remain simple and semantic, which usually makes it easier to read and maintain.

Tapestry includes sophisticated support for CSS in the form of annotation-based linking, far-future expire headers, automatic duplicate removal, and other features provided for assets.

Default style sheet

Tapestry includes a built-in style sheet, tapestry.css, in all HTML documents (documents that have an outer <html> element and a nested <head> element), as part of the "core" JavaScript stack. The core JavaScript stack also includes the CSS for Bootstrap 3.1.1.

Adding your own CSS

A page or component (for example, a layout component) that is rendering the <head> tag can add a style sheet directly in the markup.

If you want to leverage Tapestry's localization support, you may want to make use of an expansion and the "asset:" or "context:" binding prefix:

The "context:" prefix means that the remainder of the expansion is a path to a context asset, a resource in the web application root (src/main/webapp in your workspace). By contrast, the "asset:" prefix tells Tapestry to look in the class path. See Assets.

Using the @Import annotation

Another approach to adding a style sheet is to include an @Import annotation (starting with Tapestry 5.2) on your component class:

(For Tapestry 5.0 and 5.1, use the deprecated @IncludeStyleSheet annotation instead.)

As with included JavaScript libraries, each style sheet will only be added once, regardless of the number of components that include it via the annotation.

Conditionally loading IE-only style sheets

For Tapestry 5.2 and later, if you need to load a different style sheet for Internet Explorer browsers, or for certain versions of IE browsers, you can use Tapestry's built-in support for IE conditional comments. Just add something like the following to your page or component (or layout) class:

The above will render something like:

Naturally, the conditional part can be any other IE conditional expression, such as "lt IE 8".

Suppressing the default style sheet (Tapestry 5.3 and earlier)

Though it should be rarely needed, you can prevent Tapestry's default style sheet from loading by overriding the configuration in your application's module (normally AppModule.java):

AppModule.java (partial)

Note: In Tapestry 5.3 and later, the misspelled "InjectDefaultStyleheet" is corrected to "InjectDefaultStylesheet".

In Tapestry 5.4, the "core" JavaScript has a configuration into which you may inject overrides.

Overriding Bootstrap (Tapestry 5.4 and later)

The SymbolConstants.BOOTSTRAP_ROOT ("tapestry.bootstrap-root") symbol tells Tapestry where the Bootstrap css file is. You can override that symbol (see Configuration) to have it point to your own version of Bootstrap (or even to an empty file if you want to eliminate Bootstrap entirely).

AppModule.java (partial)

For the above, your bootstrap.css file would be in your app's META-INF/assets/css folder.