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Create a skin for TinyMCE

Introducing skin creation, less and icon modification.

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Create a new skin to alter the appearance of TinyMCE.

This guide assumes you have basic understanding of Node and Gulp and know your way around a terminal.

Note: The TinyMCE Skin Creator only supports TinyMCE 4.


Skin for TinyMCE 5 are written in less, a popular CSS preprocessor. Making a skin primarily involves modifying variables which you can consider a kind of API. You are not supposed to modify or override CSS rules, instead you override the less variables in your skin files. This makes updating TinyMCE much easier.

  1. Download the TinyMCE skin tools.
  2. Install all dependencies with npm install.
  3. Issue the npm run start command which also spins up a webserver for previewing the files (If you just want to build the files, use npm run build) .
  4. Point your web browser of choice to the address shown in the terminal, usually localhost:3000.

You now have the development environment set up and are ready to get to work.

Making or editing a skin

Make sure you have performed the preparation step above.


Begin by looking in the src/less/skins/ folder where you find two folders: ui which is the skins for the editor and content which skins the content within the editor. The skin imports the theme less files located in src/less/theme/. You are not supposed to edit the CSS in the theme folder, instead we have created variables for relevant css properties such as colors, margins and spacings which you use in your skin file to customize TinyMCE. This have multiple benefits: you can do quite advanced changes and still easily update TinyMCE since the only thing you have changed is a variable file, and you benefit from all the browser testing we make.

Note: The skin only changes the visual presentation of the UI and not the placement of elements. Placement of elements is done by the TinyMCE UI framework. This framework makes it possible to do complex UI layouts on all browsers without touching any CSS when plugins are created.

Creating a skin

  1. Begin by duplicating the default folder located in src/less/skins/ui/ and rename it to the name of your skin.
  2. Open the file src/less/theme/globals/global-variables.less and copy the variables you like to change to your skin.less file in the folder you duplicated in the previous step. Change the values. The variables you put in skin.less will override the default values.
  3. For more detailed customizations, review the variables in each component, such as src/less/theme/components/toolbar-button.less and copy the ones you want to change to skin.less.
  4. To style interface elements in the content, such as selection color, drag handles, table of contents, bookmarks etc, copy variables to src/less/skins/ui/<skin-name>/content.less or content.inline.less depending on if you are using the inline mode or not.
  5. Preview your skin by building it using the gulp command in your terminal.

Creating a content css

To update the appearance of the content within the editor, such as headings, quotes, lists etc you create a content css. These are located in src/less/skin/content/

  1. Create a folder in src/less/skins/content/ and create a content.less file in it. Alternatively, you can duplicate any of the existing content skins.
  2. Add the relevant element selectors for your particular use case such as h1 to h6, a, blockquote, code, table.

Moving your skin into TinyMCE

  1. Simply copy your skin and/or content skin from `build/skins/ to the corresponding folders in your TinyMCE folder.
  2. Update your init function with the skin option and/or the content_css option.

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Except as otherwise noted, the content of this page is licensed under the Creative Commons BY-NC-SA 3.0 License, and code samples are licensed under the Apache 2.0 License.