Exploring CSS Variables

CSS variables or custom properties containers

What are CSS Variables?

CSS variables, also known as custom properties containers that hold values and can be used throughout your CSS code. They allow you to store and reuse values easily. It's like having magic jars that can change the appearance of your webpage with just a few tweaks.

Using CSS Variables

Let's see how we can use CSS variables:

1. Declaration

To create a CSS variable, you use the -- prefix followed by a name. For example, --primary-color and --secondary-color .

2. Assigning Values

After declaring a CSS variable, you can assign a value to it. It can be a color, size, or any other CSS value. For example, --primary-color: blue; and --secondary-color: red; .

3. Using Variables

Once you have defined your CSS variables, you can use them in your CSS code. Just refer to the variable name using the var() function. For example, background-color: var(--primary-color); and color: var(--secondary-color); .

4. Changing Values

The cool thing about CSS variables is that you can easily change their values and update the appearance of your webpage. You can do this dynamically with JavaScript or by modifying the values directly in your CSS code.

To change the value of a CSS variable using JavaScript, you can follow these steps:

1. Select the element that has the CSS variable you want to change. This can be done using JavaScript's DOM manipulation methods like querySelector or getElementById .
2. Access the style property of the selected element to modify its inline CSS styles.
3. Use the setProperty method on the style property to set the new value for the CSS variable. Pass the CSS variable name as the first argument and the new value as the second argument.

Here's an example that demonstrates how to change the value of a CSS variable called --primary-color to blue using JavaScript:

By changing the value of the CSS variable through JavaScript, you can dynamically update styles and create interactive web experiences.

Example

Let's see an example of using CSS variables:

Hello, CSS Variables!

HTML:

CSS:

Why Use CSS Variables?

CSS variables come in handy when you want to create a consistent design with reusable values. Here are some scenarios where using CSS variables can be useful:

1. Consistent Colors

By defining your primary and secondary colors as CSS variables, you can easily update the colors throughout your website by changing just a few variable values.

2. Responsive Design

If you want to make your website responsive, CSS variables can be used to define different sizes and dimensions for different screen sizes. This way, you can adjust the layout dynamically.

3. Theming

CSS variables are particularly useful for creating themes. By defining variables for different theme colors, fonts, or spacing, you can switch between themes effortlessly.

4. Animation and Transitions

When it comes to creating animations or transitions, CSS variables allow you to change values smoothly, resulting in visually appealing effects.

Reusable values in your CSS

CSS variables allow you to create reusable values in your CSS code, making it easier to maintain and update the appearance of your webpages. By using variables, you can create consistent designs, implement responsive layouts, and add dynamic theming and animations. Keep exploring the exciting world of CSS variables and unleash your creativity!

Best Practices for Using CSS Variables

CSS variables, also known as CSS custom properties, provide a powerful way to manage and reuse values in your stylesheets. Here are some best practices to consider when using CSS variables in your projects:

Centralize and Reuse Values

CSS variables are excellent for centralizing commonly used values, such as colors, font sizes, or spacing, in a single place. By defining variables at the root level of your stylesheets, you can easily update multiple styles across your entire project by modifying just one variable.

Use Variables for Flexible Theming

CSS variables are ideal for creating flexible theming options in your web applications. By defining variables for theme-specific values like colors or backgrounds, you can switch themes dynamically by changing the values of the variables. This provides a convenient way to implement light and dark themes or allow users to customize the visual appearance of your site.

Separate Variables for Global and Component-Specific Styles

To improve maintainability and reusability, it's beneficial to separate CSS variables for global styles and component-specific styles. Global variables can hold values that apply across your entire project, while component-specific variables can be scoped to individual components, allowing for encapsulation and easier customization.

CSS variables are like containers that hold special values used for styling a website. When using CSS variables, it's a good idea to keep them organized and separate for different parts of the website. This is called "scoping."

Global Variables for the Whole Website

Some variables, called "global variables," can be used everywhere on the website. These variables hold values that are shared across different pages and sections, such as colors or font sizes. By using global variables, we can easily change these values in one place, and it will automatically update them everywhere they are used.

Component-Specific Variables for Individual Parts

Other variables, called "component-specific variables," are only used for specific parts of the website, like a header, footer, or a particular section. These variables are like special containers that hold values just for that specific part. By using component-specific variables, we can make changes to a particular part without affecting other parts of the website. It's like having different containers for each section, making it easier to change how things look in just one section without touching the rest.

Remember, by separating variables for different parts of the website, we can keep things organized, make changes more easily, and make sure that changes in one part don't accidentally affect other parts.

Keep Variable Names Descriptive

When naming CSS variables, it's important to use clear and descriptive names that convey their purpose. By using meaningful variable names, you enhance the readability and maintainability of your code, making it easier for others (and your future self) to understand and modify your styles.

Be Mindful of Performance

While CSS variables are incredibly useful, keep in mind that excessive use of variables can impact performance. Since CSS variables are resolved at runtime, using a large number of variables or nesting variables within other variables may introduce additional overhead. Therefore, it's recommended to strike a balance between the convenience of variables and the performance considerations of your project.

By following these best practices, you can effectively leverage CSS variables to improve the maintainability, flexibility, and theming capabilities of your CSS code.