A css file extension is commonly used for text files that contain Cascading Style Sheets data, which are used on websites and define graphic layout and look of webpages.

There is one other file type using
the CSS file extension!

empty icon.css - Statistica data sheet

Detailed description

Software that open css file

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CSS file extension - Cascading Style Sheets

What is css file? How to open css files?

File type specification:

Internet related file type icon Internet related file type

The css file extension is associated with Cascading Style Sheets (CSS). The css files are used to format the contents of web pages.

A css file contains customized, global properties and other information about how to display HTML elements. It can define the size, background, colors, fonts, line spacing, indentation, borders, formats and location of HTML elements.

Basically, the css files are used to create a similar look and feel across whole websites. The .css files are also used to reduce the amount of work and HTML code generated by consolidating display properties into one single file. The .css files are stored in a plain text format.

The style sheets have existed in one form or another since the beginnings of SGML in the 1970s. Cascading Style Sheets were developed as a means for creating a consistent approach to providing style information for web documents.

The Cascading Style Sheets (CSS) helps Web developers create a uniform look for several pages within a Web site. Instead of defining the style of each table and each block of text within a page's HTML, commonly used styles need to be defined only once in a CSS document.
Once the style is defined in cascading style sheet, it can be used by any page that references the .css file. What more, the CSS allows to easy change styles across several pages at once.
For example, a Web developer is able to change the default font size from 12pt to 14pt for ten pages of his Web site at once. If the pages all reference to the same style sheet, the text size only needs to be changed on the style sheet and all the pages will have their font changed.

While Cascading Style Sheets are great for creating text styles, they are really helpful for formatting other aspects of the Web page layout as well. For example, the .css file can be used to define the cell padding of table cells, the style, thickness, and color of a table's border, and the padding around images or other objects. CSS gives Web developers much more control over how their web pages will look compared what the HTML format offers. For this very reason, most internet pages today incorporate cascading style sheets.

The CSS specifications are maintained by the World Wide Web Consortium (W3C).

MIME types:
text/css is registered for use with CSS by RFC 2318.

Updated: May 11, 2024

The default software associated to open css file:

Rapid CSS Editor picture or screenshot

Rapid CSS Editor  Microsoft Windows software

Company or developer:
Blumentals Software

Rapid CSS Editor enables users to quickly and easily create and edit cascading style sheets of any size and complexity.

Top Style For Windows  Microsoft Windows software

Company or developer:

TopStyle is a powerful HTML5 & CSS3 editor for Windows. It contains powerful tools for building standards-compliant web sites.

Adobe Creative Cloud icon

Adobe Systems Incorporated logoAdobe Creative Cloud  Multiplatform software

Company or developer:
Adobe Systems Incorporated

Adobe Creative Cloud is latest member of Creative family. With this version Adobe moved from one-time fee to subscription based model, while no longer plans to offer one time purchase options like the users were used. There is either annual or monthly fee for using the whole bundle or just one program.

Related articles:

Cross-browser testing tools

Help how to open:

Use any suitable text editor or development suite to open or edit the .css files. You can also view the .css files with any modern internet browser.

How to convert:

You can convert HTML files to CSS with the use of some SEO tools available on the internet, such as TABLE2CSS.

Find converter to css file type:

psd to css

scss to css

Related links:

Cascading Style Sheets home page

Cascading Style Sheets at Wikipedia

Informations about this MIME type

List of software applications associated to the .css file extension

Recommended software programs are sorted by OS platform (Windows, macOS, Linux, iOS, Android etc.)
and possible program actions that can be done with the file: like open css file, edit css file, convert css file, view css file, play css file etc. (if exist software for corresponding action in File-Extensions.org's database).

Click on the tab below to simply browse between the application actions, to quickly get a list of recommended software, which is able to perform the specified software action, such as opening, editing or converting css files.

Software that open css file - Cascading Style Sheets

Programs supporting the exension css on the main platforms Windows, Mac, Linux or mobile. Click on the link to get more information about listed programs for open css file action.

Microsoft Windows:

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