Dynamic Color Palettes: A Complete Guide to CSS Variables

Dynamic Color Palettes: A Complete Guide to CSS Variables


As a web developer, creating a cohesive color palette is essential for designing visually pleasing websites. Thankfully, CSS variables make it easy to define and use a consistent color scheme across your site.

First, let’s understand what CSS variables are. They are custom properties that you can define and use in your CSS code. The syntax for defining a CSS variable is as follows:

:root {
  --my-variable-name: #ff7f50;

Here, we are defining a variable called —my-variable-name and giving it a value of #ff7f50, which is a shade of red.

Now, let’s use this variable to define a color palette for your own website.

Here’s an example:

:root {
  --primary-color: #2b2d42;
  --secondary-color: #8d99ae;
  --accent-color: #ef233c;

body {
  background-color: var(--primary-color);

h1 {
  color: var(--secondary-color);

a {
  color: var(--accent-color);

In this example, we’ve defined three variables --primary-color, --secondary-color, and --accent-color, and assigned them different shades of colors. We then use these variables throughout our CSS code to define the background color of the body, text color of headings, and link color.

What is the Best Selector to use for Variable Colors in CSS?

The best selector to use for variable colors in CSS is the :root pseudo-class. This selector matches the root element of the document, which in HTML is usually the <html> element.
Using the :root selector to define your color variables has several benefits:

  1. The variables defined in :root are available globally throughout the document, making it easy to use them across different elements and components.
  2. Because :root is a top-level selector, it has a high specificity, which means it can override other selectors that define the same property. This is useful if you need to change the color of an element across your entire site, without having to update every instance of the color individually.
  3. Using :root for your color variables is a common convention in CSS, which makes your code more readable and easier to understand for other developers who may be working on your project.

Best practices for using CSS variables for colors in large-scale

CSS variables are a powerful tool for managing colors in large-scale web projects. When used correctly, they can make it easy to update the color scheme of a website, without having to manually change every instance of a color throughout the CSS file. Here are some best practices to follow when using CSS variables for colors in your project:

  1. Define your variables in one place: To make your CSS more maintainable, it’s a good idea to define your color variables in one place, such as the :root selector. This will make it easy to update the colors across your entire website by simply changing the values of the variables in one location.
  2. Name your variables descriptively: When naming your variables, make sure to use names that describe the purpose of the color, such as --primary-color or --background-color. This will make it easier for other developers (or even yourself) to understand what the variable represents, and reduce confusion when updating the colors later on.
  3. Use fallback values: While CSS variables are well-supported by modern browsers, it’s always a good idea to provide fallback values for older browsers that don’t support them. You can do this by including the fallback color value after the variable value, separated by a comma.

For example:

background-color: var(--primary-color, #007bff);

In this example, the background color will use the value of the --primary-color variable if it’s available, but will fall back to the color #007bff if the variable isn’t supported.

  1. Don’t overuse variables: While CSS variables are a great tool, it’s important not to go overboard with them. Defining too many variables can make your code harder to read and maintain, so try to keep them to a reasonable number.

By following these best practices, you can use CSS variables to manage your color scheme in large-scale web projects, making it easier to update your website’s look and feel without sacrificing maintainability.


CSS variables are a valuable tool for web developers when it comes to managing colors in large-scale projects. By defining variables in one place and naming them descriptively, it is easier to update the colors across the website. It’s also essential to include fallback values for older browsers and avoid defining too many variables that could make the code harder to read and maintain.

With these best practices in mind, using CSS variables can improve the maintainability of a website’s color scheme while making it easier to update its look and feel.

Further reading

Want to learn more about CSS custom Properties (variables)? Then check out – Using CSS custom properties (variables) – CSS: Cascading Style Sheets | MDN

See also

What is CSS? Basics Explained
What are the 3 Ways to Style in CSS?
What are the Most Common CSS Units?

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