Bootstrap - Sass & Custom Theming in Bootstrap

Bootstrap is built using Sass (Syntactically Awesome Stylesheets), which is a CSS preprocessor. Sass allows developers to use variables, nesting, functions, and reusable code to make styling more efficient and maintainable.

Bootstrap provides a large set of Sass variables that control colors, spacing, breakpoints, typography, borders, shadows, and more. For example, instead of manually changing button colors everywhere, you can modify a single variable like $primary in the Sass file, and the change applies across the entire project.

This makes custom theming possible. You can:

• Create your own brand color system

• Adjust grid breakpoints

• Modify default spacing scale

• Remove unused components before compiling

To use Sass customization, Bootstrap must be installed via NPM, not CDN. You then import Bootstrap’s source files into your custom Sass file and override variables before compilation.

Why this matters for students:

• It teaches scalable design system thinking

• It reduces repetitive CSS

• It prepares you for real-world frontend workflows

Without Sass, you are only using Bootstrap as-is. With Sass, you control Bootstrap internally.