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What is the .CSS File Extension?

.CSS File Extension Description:

The CSS, short for Cascading Style Sheets, and uses the CSS file extension in order to describe how a document written in a markup language can be presented. Its most common use is to style web pages written in HTML and XHTML, but can also be applied to XML as well as SVG and XUL documents.

The CSS file extension is used to define fonts, colors, layout, and other aspects of presenting a document. It is primarily designed to separate the content of a document written in HTML to the presentation of a document written in CSS. As a result, it improves content accessibility, reduces repetition in the structural content, and provides more control and flexibility in the specification of presentation characteristics.

A file with the .css file extension has a simple syntax. It uses several English keywords to specify the names of different style properties and has the same markup page presented for different rendering methods (on-screen, in print, by voice, and Braille-based devices). The file is presented in the so-called "cascade" in which weights or priorities are calculated and assigned to rules. Non-visual styles such as the speed and emphasis to which text is read out by aural text readers are also defined in the files with the .css file extension.

When using CSS, it is preferable to use external CSS keep it separate from your HTML. Placing it in a separate file allows the web designer to completely differentiate between the HTML content and the CSS design. External CSS files contain only the CSS code and are saved with the CSS file extension. The file with the .css file extension is then referenced in your HTML by using the <link> instead of the <style>.

The external CSS keeps your website content and design separate making your CSS code much easier to reuse if it is placed in a separate file. You can also make drastic changes to your web pages with just a few changes to your single CSS file.

The file with the .css file extension can be created and saved using the Notepad. When saving, however, make sure you are not saving the file as a text with the .txt file extension but as a file with the .css file extension.

Previously, a few web servers were particularly configured to actually serve files with the .css file extension as mime type application/x-pointplus. During those times, the PointPlus Maker application was used in converting PowerPoint files to Compact Slide Show files by utilizing the CSS file extension so that the configured web servers gave signal to their client browsers that the files with the .css file extension were x-pointplus media type.

Author: W3C
Author URL:
Related Applications: CSS, HTML
Common Path: N/A


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Do you have errors with .CSS files?

The Common Reason for .CSS files Errors:

A common and likely reason for .CSS files errors is corruption in the Windows program registry - fixing is needed to protect against more damage in other applications and/or system devices. Receiving these errors puts your PC at risk for fatal crashes, blue screen errors and even system device failure.

Symptoms of .CSS files Errors:

Typical symptoms with .CSS files errors include slower computer speed, extended application load times, failure opening files, excessive suspensions in program routines, applications exits without an error, input halts and applications crash.

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How to Fix .CSS File Extension Errors    |    Scan for .CSS File Extension Errors    |    What is the .CSS File Extension?