Bootstrap is a popular front-end framework that provides a solid foundation for building responsive and visually appealing websites. However, there may be times when you want to customize Bootstrap’s default styles to match your project’s unique design requirements. In this article, we will explore how to override Bootstrap in CSS, utilizing specific keywords to help us navigate through the process.

Understanding Bootstrap CSS

Before we delve into the steps of overriding Bootstrap in CSS, let’s gain a clear understanding of what Bootstrap CSS is and why you might want to customize it.

What is Bootstrap CSS?

Bootstrap CSS is a set of predefined styles and classes that come bundled with the Bootstrap framework. These styles are designed to make it easier to create consistent and responsive layouts quickly. While Bootstrap provides a fantastic starting point for web development, there are situations where you may need to tweak the default styles to make your project stand out.

The Two Main Methods

There are two primary ways to override Bootstrap CSS effectively. Let’s explore each method, highlighting the keywords as we go.

1. Override using a Higher Specificity Selector and Properties via CSS

One approach to customizing Bootstrap is by using higher specificity selectors and properties in your CSS. This method allows you to target specific elements and modify their styles without altering Bootstrap’s core CSS files.

To get started, create a custom CSS file (e.g., custom.css) and include it in your HTML after Bootstrap:

<!-- Bootstrap CSS -->
<link rel="stylesheet" href="bootstrap.min.css">

<!-- Custom CSS for overrides -->
<link rel="stylesheet" href="custom.css">

Now, you can override Bootstrap styles in your custom.css file. For example, if you want to change the color of the primary button:

/* custom.css */
.btn-primary {
    background-color: #FC7F66;
    border-color: #FC7F66;

Remember that the specificity of your custom CSS should match or exceed that of Bootstrap’s styles for effective overrides.

An even more efficient way to customize Bootstrap is by utilizing Sass variables and mixins. This method not only allows for easy customization but also minimizes the risk of unintentionally overriding Bootstrap’s default styles.

Here are the steps to follow, along with the associated keywords:

a. Set Up a Local Environment

To begin, set up a local development environment capable of compiling Sass files. There are various tools available for this, such as Gulp 4 and BrowserSync.

b. Modify Sass Variables

Once your environment is ready, locate the _variables.scss file. Here, you can make changes to variables like $primary to customize colors, sizing, and other style attributes. When you update a variable, it affects all Bootstrap elements that use it, including buttons, badges, and navigation items.

This method of using Sass variables is a game-changer because it streamlines customization and eliminates the need to override individual classes one by one.


In this article, we explored how to override Bootstrap in CSS, focusing on two main methods: using higher specificity selectors and properties via CSS and utilizing Sass variables. By following these approaches, you can tailor Bootstrap’s default styles to match your project’s unique design requirements efficiently.

Remember that while customizing Bootstrap can greatly enhance your website’s visual appeal, it’s essential to strike a balance between customization and maintaining the framework’s core functionality.

So go ahead, harness the power of CSS, Sass variables, and the knowledge shared in this article to take control of your Bootstrap-based projects and create stunning, one-of-a-kind websites!


What are the best practices for overriding Bootstrap in CSS?

When it comes to overriding Bootstrap in CSS, following best practices ensures a smoother and more efficient customization process:

Create a Separate Custom CSS File: Always create a separate CSS file for your custom styles. This separation keeps your modifications organized and makes it easier to manage and maintain your code.

Use Specific Selectors: To ensure your custom styles override Bootstrap’s default styles, use selectors with equal or higher specificity. This helps prevent unintended style conflicts.

Avoid Modifying Bootstrap Files: Never directly modify Bootstrap’s core CSS files. Instead, rely on your custom CSS file to make changes. This prevents issues when updating Bootstrap in the future.

Prioritize Mobile-First Design: Bootstrap is built with a mobile-first approach. When customizing, ensure that your styles remain responsive and adapt well to smaller screens.

Document Your Changes: Keep clear documentation of your customizations. This will help you and your team understand the purpose of each modification and make future updates more manageable.

Test Thoroughly: Test your customized Bootstrap styles across various browsers and devices to ensure consistent rendering and functionality.

    Are there any potential issues when overriding Bootstrap CSS?

    While overriding Bootstrap CSS offers flexibility, it can introduce potential issues if not done carefully:

    Version Compatibility: Upgrading Bootstrap to a newer version may require adjustments to your custom styles to ensure compatibility.

    Specificity Conflicts: If your custom CSS selectors are not specific enough, they may not override Bootstrap’s styles as expected. Be mindful of the specificity of your selectors.

    Maintenance Challenges: Keeping track of your customizations and updating them as your project evolves can be challenging, especially if the customizations are extensive.

    Performance: Overriding styles may lead to larger CSS files, potentially affecting page load times. Use minification and optimization techniques to mitigate this.

    Cross-Browser Compatibility: Customizations might behave differently across different browsers. Extensive testing is essential to address compatibility issues.

    Can I use Sass variables to customize Bootstrap styles?

    Yes, you can use Sass variables to customize Bootstrap styles. Bootstrap provides a set of Sass variables that control various aspects of the framework’s appearance. By modifying these variables in your custom Sass files, you can easily customize Bootstrap’s colors, fonts, spacing, and more.

    What are the benefits of customizing Bootstrap using Sass variables?

    Customizing Bootstrap using Sass variables offers several advantages:

    Efficiency: Sass variables allow you to make global style changes by updating a single variable. This efficiency saves time and reduces the risk of errors.

    Consistency: When you modify a Sass variable, the change is applied consistently throughout your project, ensuring a cohesive design.

    Easy Maintenance: Customizations made through Sass variables are easier to maintain and update when compared to manually overriding CSS classes.

    Modularity: Sass variables promote a modular approach to styling, making it easier to swap themes or adapt to design changes.

    Future-Proofing: By customizing using Sass variables, you are less likely to encounter issues when updating to newer versions of Bootstrap. Your customizations can be preserved with minimal effort.

    Collaboration: Sass variables make it easier for design and development teams to collaborate, as they provide a clear and centralized way to manage style changes.

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