Designing websites using CSS

Kentico websites use standard CSS to define the appearance and design of pages and their components. The system organizes CSS code into stylesheets.

There are two ways in which we recommend that you style your website:

Also on this page:

Styling websites using the CSS stylesheets application

If you don’t need any automation tools, like preprocessors and bundling tools, we recommend using the CSS stylesheets application to style your website. Styles managed in the CSS application are stored in the database instead of the file system.

  1. Open the CSS Stylesheets application.

  2. Create a New CSS stylesheet. We recommend the following naming convention, where YourSite is the Code name of your site:

    • Display name: YourSite - Style

      Creating a stylesheet

  3. Save.

  4. Open the Sites application.

  5. Edit the site in which you want to include the stylesheet.

  6. Select the stylesheet you just created in Site CSS stylesheet.

    Assigning a stylesheet to a site

  7. Save.

This is now the site’s main CSS stylesheet. You may consider separating your CSS into multiple stylesheets for simpler management. For example, you may want to use a SiteName - Navigation stylesheet for your website’s navigation and SiteName - Landing page stylesheet for a specific landing page on your site. You would then combine all the specific stylesheets in the main stylesheet that you just created. This is done using the {% CSS[“Stylesheet”] #%} macro. The main stylesheet can then contain only general styles, like the general styles for the html, body, and form elements that apply to the whole website.

Combining multiple stylesheets in one

On the actual live site, changes made to CSS stylesheets only take effect after you clear your browser cache and/or restart the application (System -> Restart application).

- If you wish to use a dynamic stylesheet language, you need to register a CSS preprocessor in the system. - You can download a LESS Preprocessor from the Kentico Marketplace. - The system provides a CSS validator that allows you to check if the styles of individual pages are valid against CSS standards.

Using automation tools to style websites

If you want to make use preprocessors, code hinting or CSS bundling when creating your CSS, you need to store your CSS files on the file system.

This approach doesn’t make use of the CSS stylesheets application.

  1. Create a Stylesheets folder in <project folder>\CMS\<site name>. For example C:\inetpub\wwwroot\Kentico\CMS\CorporateSite\Stylesheets.

  2. Set your automation tools to create CSS files in the folder.

  3. Open the Pages application.

  4. Select the master page and switch to the Master page tab.

  5. Include the stylesheets in the head section of the page. For example, for a Styles.css file, you would enter the following:

    <link href=“~/CMSPages/GetResource.ashx?stylesheetfile=/{% CurrentSiteName %}/Stylesheets/Styles.css” type=“text/css” rel=“stylesheet” />

    Linking stylesheets stored on the file system in the page

  6. Save.

The stylesheets are now included in all the pages on the site.

Assigning stylesheets to sites and pages

Each website in the system has a default CSS stylesheet. To assign a stylesheet to a site:

  1. Open the Sites application.
  2. Edit () the site.
  3. Select an option in the Site CSS stylesheet field. You can only choose stylesheets that are allowed for the given site (on the Sites tab of the stylesheet editing interface).
  4. Click Save.

Individual pages either use the website’s stylesheet, or you can assign a different stylesheet. By default, pages automatically inherit the stylesheet from their parent page in the content tree, so you can quickly set the stylesheet for entire website sections.

  1. Open the Pages application.
  2. Select the page in the content tree.
  3. Open the Properties -> General tab.
  4. Select the CSS stylesheet.
    • Uncheck the Inherit box to use a different stylesheet than the parent page.
    • You can only choose stylesheets that are allowed for the given site (on the Sites tab of the stylesheet editing interface).
  5. Click Save.

When displaying pages, the system automatically adds a request that loads the assigned stylesheet into the HTML code.

Tip: When assigning stylesheets to sites or pages, you can directly create new stylesheets (click New) or edit the code of the selected stylesheet (click Edit).

Stylesheet URLs

You can access stylesheets using a URL in the following format:

~/CMSPages/GetCSS.aspx?stylesheetname=<stylesheet code name>

The GetCSS.aspx system page retrieves unmodified, user‑friendly stylesheet code even if minification of stylesheet resources is enabled.

Default styling of Kentico components

Kentico projects contain the Skin.css physical stylesheet by default, which provides basic styling for web parts and other components on the live site.

A global Skin.css file is located in the ~/App_Themes/Global folder. Individual sites have their own dedicated Skin.css files, which import the global Skin.css stylesheet. For example, the Corporate Site sample site has its Skin.css file in the ~/App_Themes/CorporateSite folder. If you edit the file, you can see that the stylesheet imports the global Skin.css file, and contains several additional styles for the Corporate Site.

The styles in Skin.css use the .ContentBody class to have stronger (more specific) selectors.

Note: The Skin.css stylesheet is linked by default on the pages of all Kentico sample sites except the Blank Site and ASPX Blank Site.

Creating custom component styles for sites

The default Skin.css styles may interfere with your site’s custom stylesheets.

Use one of the following approaches to implement custom component styling for your website:

  • Do not include Skin.css on your site, define all required styles as Kentico CSS stylesheets or CSS files on the file system.
  • Use the !important directive or stronger selectors (with more classes) in your CSS to override the default styles
  • Edit the skin stylesheets directly

Note: If you edit the global skin stylesheet, the changes affect all sites in your Kentico instance, and may be overwritten when you upgrade the site to a new version of Kentico.

LESS code base

Skin.css is generated from the LESS Skin.less file. You can modify Skin.css directly, but you lose the advantages of the structured, commented and more readable .less file.

The Skin.less file is located in ~/App_Themes/Global and includes multiple skin sub-files in the ~/App_Themes/Global/Skin folder.

If you are uncertain how to work with LESS, you can find an article describing the process at Using the LESS CSS Preprocessor for Smarter Style Sheets.

Using CSS blocks for easier navigation in CSS code

You can use comments in format /* #BLOCKNAME# */ to improve navigation in the code of large CSS stylesheets. You can access blocks within the stylesheet code through the bookmark list next to the editor. 

To create a hierarchy of sub-blocks, separate the names of individual block levels using forward slashes, for example: /* #BLOCKNAME/SUBBLOCK# */


/* #Menu# */


/* #Menu/TreeMenu# */


/* #Menu/MainMenu# */


Creating sections in stylesheets

Browser and language‑specific styles

The system automatically assigns CSS classes to the <body> element of pages according to the characteristics of the selected language (the text direction and exact culture) and the browser used to display the page. For example:

<body class="LTR IE IE9 ENUS">

 Four types of classes are added:

  • Text direction - the LTR class is assigned for left‑to‑right languages, and RTL for right‑to‑left.

  • Browser type - added according to the browser in which the page is opened. The following classes are used:


    Class names

    Internet Explorer




    Google Chrome

    Chrome, Safari





  • Browser version - the class name is the same as for the browser type, but with the number of the browser’s major version appended, for example IE9, Gecko26 etc.

  • Culture - the name of the class is added based on the culture code of the page’s content (without the hyphen), for example ENUS for pages using the en-US culture.

This feature allows you to style page elements differently according to the browsing environment of the current visitor. You can define styles for any combination of the classes mentioned above.

For example, you can add the following into a website’s stylesheet:

_:-ms-fullscreen, :root .ie11up .MyFont 
   font-size: 20px;

 .Opera .MyFont 
   font-size: 18px;

Now elements styled using the MyFont class have a different font size when viewed in Internet Explorer 11 or Opera (all versions) browsers.