This lesson shows how to do a basic setup of css-theming in your app.

Following are three things you have to do to setup your project to work with css-theming:

  • Optionally define themes in your variables file.
  • Import the main css-theming SCSS file from your app scss file.
  • Call initializeTheming from javascript/typescript in the startup of your app.

Defining system themes #

By default, css-theming gives you two themes, one light theme called default, and another dark theme called default-dark. You’re free to completely override this to define your own system themes.

You override this in your variables file. A variables file is a SCSS file you use that doesn’t emit any real CSS. It contains all the definitions (SCSS variables, mixins, functions, etc.,) of your app. You usually import this file in all your concrete SCSS files; those would be the main app SCSS file, and SCSS files for components if your app is a SPA.

The following is an example variables file that defines three themes:

// Override the system defined themes
$ct-themes: (
  'default': (
    'brightness': 'light',
  'default-dark': (
    'brightness': 'dark',
  'high-contrast': (
    'brightness': 'light',

@import '../../node_modules/css-theming/src/scss/pure';

We import the pure SCSS file from css-theming after we override the variables we want, as shown in the above snippet. This pure file is what contains all the definitions of css-theming, including all SCSS variables it defines (themes, colors, swatches, etc.).

Note: You can think of this pure file as the variables file of css-theming.

What we’re doing here is almost exactly the same as what you’d do when using something like bootstrap for example. You would import bootstrap’s variables file in all your SCSS files, but you only import bootstrap’s main file in your main app SCSS file.

Importing the main css-theming SCSS file #

In your main app SCSS file:

@import '../../node_modules/css-theming/src/scss/css-theming';

Calling initializeTheming #

Call initializeTheming as soon as you can in your app. This can be the created lifecycle hook of the main app component in a Vue.js app, the constructor of the main app component in an angular app, etc.

import {
} from 'css-theming';

// Initializes the default category themes
initializeTheming(/* theme */);

In this basic example, initializeTheming can take the theme that you want to initialize at first. Let’s assume we always want to load default-dark whenever the application loads:

import {
} from 'css-theming';

// Initializes the default category themes

Of course, instead of hard coding the initial theme you load, you can easily get this value from local storage or from your backend if you save the user’s preference there.

Note: If you register additional category themes you’ll call initializeTheming once for each category, as we’ll explain in a later lesson.

Setting a new theme #

You tell css-theming to change the current theme by calling setTheme:

import {
} from 'css-theming';

// Initializes the default category themes

This of course can be in response to a button click for example, that the user clicks on to choose what theme they want to activate.

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