Introduction to CSS Variables

Published on July 24, 2020

Introduction

In this post, we will explore CSS variables and how they can be used to simplify and improve the maintenance of your frontend codebase. We will start with the basics and then move on to more advanced topics…

What are CSS Variables?

CSS variables are a way to define values that can be used throughout your stylesheet. They are defined using the -- symbol, followed by the name of the variable, and the value you want to assign to it. For example:

:root {
  --primary-color: #3498db;
}

h1 {
  color: var(--primary-color);
}

In this example, we define a variable called --primary-color and assign it the value #3498db. We can then use this variable in any other selector to set the color property.

Benefits of Using CSS Variables

There are several benefits to using CSS variables:

1. Improved code reuse: With CSS variables, you can define a value once and use it throughout your stylesheet. This makes your code easier to read and maintain, as you don’t have to repeat the same values over and over again.
2. Consistency: CSS variables help keep your styling consistent across different components of your application. By defining colors, font sizes, and other style properties in a single place, you can ensure that they are used consistently throughout your app.
3. Easier to update: When using CSS variables, you only need to update the value of the variable in one place to update all instances where it is being used. This makes it easier to make changes to your styling without having to go through your entire codebase and update each instance manually.

Example of Using CSS Variables

Let’s say we have a button that we want to style with a specific color. We can define the --primary-color variable in our :root selector and then use it in our button styles:

:root {
  --primary-color: #3498db;
}

button {
  background-color: var(--primary-color);
  color: white;
  padding: 10px;
  border: none;
  border-radius: 5px;
  cursor: pointer;
}

In this example, we define the --primary-color variable and then use it in our button styles to set the background-color, color, padding, border, border-radius, and cursor properties.

Conclusion

CSS variables are a powerful way to simplify and improve the maintenance of your frontend codebase. With them, you can define values that can be used throughout your stylesheet, making your code easier to read and maintain. By consistently using CSS variables, you can ensure that your styling is consistent across different components of your application and make it easier to update your styles when needed.