Manage stylesheets

This article is machine translated.

As already mentioned in the section, Contao in Quick Look, cascading stylesheets, CSS for short, are the formatting tool of choice for formatting web pages. If you don’t have at least some basic knowledge of CSS, you should learn it now, because creating or adapting a theme is not possible without CSS knowledge. A very good introduction to the topic can be found in the book series “Little Boxes” by Peter Müller.

Contao provides a convenient backend module for stylesheet management that allows you to enter all format definitions in a single input mask. The creation of the actual CSS file is done automatically in the background.

The internal CSS editor is deprecated and will be removed
in one of the next Contao versions! please export your existing stylesheets and add them as external stylesheets to the page layout.

Set media types

The media type of a style sheet determines the type of end device for which it is valid. For example, if you create a stylesheet with a handheld media type, it will only be included if you access the page from a handheld PC. If you access the page with your browser, it will be automatically skipped. The following media types are available:

Media type Explanation
aural The stylesheet applies to computer generated speech.
braille The stylesheet applies to output devices with a Braille line for blind users.
embossed The stylesheet applies to Braille printers.
handheld The stylesheet applies to handheld PCs and smartphones. However, not all end devices request this media type; the iPhone, for example, always uses screen style sheets.
print The stylesheet is valid for the print version of the website.
projection The stylesheet is valid for presentation with beamers and similar devices.
screen The stylesheet is valid for screen output (standard for web pages).
tty The stylesheet applies to non-graphical output media with fixed character width.
tv The stylesheet applies to TV-like output media with coarse resolution.
all The stylesheet applies to all media types mentioned.

You define the media type of a style sheet in the stylesheet settings.

The media types relevant for web pages are screen and print.

Conditional Comments

Conditional Comments are proprietary instructions that are only understood by Internet Explorer and allow, among other things, the inclusion of specific stylesheets and other scripts. In such a stylesheet you can, for example, fix display errors separately, which are unfortunately abundant in older versions of Internet Explorer.

The condition of a conditional comment can be read as follows:

Condition Declaration
if IE Applies to all versions of Internet Explorer.
if IE 6 Applies only to version 6.
if lt IE 6 Applies to all versions smaller than 6 **(**less than).
if lte IE 6 Applies to all versions smaller or equal to 6 **(**less than or equals).
if gt IE 6 Applies to all versions greater than 6 .
if gte IE 6 Applies to all versions greater than or equal to 6 **(**greater than or equals).

Now that fixing Internet Explorer errors has become part of a web designer’s everyday work, the integration of stylesheets using conditional comments has been integrated into stylesheet management.

Create format definitions

To create format definitions, you need to know two things: What are the class names of the Contao elements (the so-called selectors) and in which order are the format definitions stored?

Class names of the Contao elements

The CSS class names of the Contao elements are logical throughout. Content elements begin with the prefixce_ (for content element), followed by the type of the content element. For example, a text element has the classce_text, a picture element has the class ce_image.

The same applies to modules, except that they start with the prefix (for mod_modules). For example, the “Navigation Menu” module has the classmod_navigation, the “Message List” module the classmod_newslist. If you are not sure about the class of an element, just look in the source code of the web page.

In your stylesheet, you can then use the class name of an element to assign a format to it. For example, the followingCSS statement sets the outer spacing of a Contao text element to 24 pixels:

.ce_text {
    margin: 24px;
}

In Contao, however, you cannot touch this style sheet at all because you can specify all formats in the input mask. Only the part in front of the curly brackets, the so-called selector, has to be entered manually in the field provided.

Set the outer distance in the stylesheet editor

Sequence of the format definitions

The order of the format definitions plays an important role in Cascading Stylesheets, because each statement in a subsequent format definition can be overwritten. This feature is especially useful for compensating browser-specific peculiarities, for example:

/* Außenabstand für alle Browser */
mod_search {
    margin: 24px;
}

/* Korrektur im Internet Explorer 6 */
html .mod_search {
    margin: 18px;
}

If the order of the format definitions were reversed, the specific format for Internet Explorer would be loaded first and then overwritten by the generally valid format for all browsers. The specific statement would therefore never be applied, and the outer distance would always be 24 pixels.

You can change the order of the records in Contao using the navigation iconsMove format definition Drag&Drop orMove format definition Move andInsert after format definition then Insert.

You can also assign a category to format definitions so that you can later filter records by that category and more easily identify related definitions. These categories are only used for a better overview in the backend and are not used for sorting in the stylesheet itself.

Export stylesheets

You can export individual stylesheets by clicking on the navigationExport style sheet icon Export Stylesheet behind the stylesheet.

Import stylesheets

To enable you to edit existing stylesheets with the internal stylesheet editor, the stylesheets module offers you the possibility to import CSS files. To do this, first transfer your CSS file to the Contao upload directory, and then click on the CSS Import button. A page with a file browser will open, from which you can select the stylesheets to import.