Bulma vs Primer CSS
Which should you use? A side-by-side look at what each one does, who it suits, what it costs, how hard it is to set up, and where each falls short.
Open source · MIT
A CSS framework built on Flexbox that gives you styled layout and UI classes.
Open source · MIT
GitHub's CSS design system, distributed as Sass styles for building GitHub-style interfaces.
The short answer
Choose Bulma if you need…
- Developers who want a quick, consistent styling baseline for a web page
- Projects that already have their own JavaScript and only need a style layer
- Teams that want to customize styles through Sass variables
- Developers working with Vue, React, or other frameworks who want Bulma-based component libraries
Choose Primer CSS if you need…
- Developers who want to match GitHub's visual style in an existing web project
- Teams already using Sass who want ready-made UI styles and utility classes
- Maintainers of existing products that already depend on @primer/css
Side-by-side
| Bulma | Primer CSS | |
|---|---|---|
| Type | Library | Library |
| Price | Free and open source | Free and open source |
| Licence | MIT | MIT |
| GitHub stars | 50k | 13.1k |
| Setup difficulty | Beginner | Intermediate |
| How you get it | Install with a package manager | Install with a package manager |
| Main language | CSS | SCSS |
| Last code update | 46 days ago | 5 days ago |
What each one is
Bulma
Bulma is a CSS framework based on Flexbox. It ships as a single CSS file with ready-made classes for layout and common interface elements, so you can style a web page without writing much custom CSS. It contains no JavaScript, so you add your own scripts for any interactive behavior.
Primer CSS
Primer CSS is the CSS implementation of GitHub's Primer Design System. It provides Sass (SCSS) source files that supply GitHub's styles, components and utility classes, which developers can import into their own projects. The README says the project is now in maintenance-only mode, and points people to primer/react or primer/view_components for newer patterns.
Best for
Bulma
- Developers who want a quick, consistent styling baseline for a web page
- Projects that already have their own JavaScript and only need a style layer
- Teams that want to customize styles through Sass variables
- Developers working with Vue, React, or other frameworks who want Bulma-based component libraries
Primer CSS
- Developers who want to match GitHub's visual style in an existing web project
- Teams already using Sass who want ready-made UI styles and utility classes
- Maintainers of existing products that already depend on @primer/css
Strengths
Bulma
- Based on Flexbox, with a single CSS file as its output
- No JavaScript included, so it does not force a particular JS environment
- Customizable through Sass source files and variables
Primer CSS
- Backed by GitHub and published on npm under the MIT license
- Documentation site is linked from the README and covers getting started, components and theme
- Modular imports let you include only the parts you need
Not ideal for
Bulma
- People who need interactive components like modals or dropdowns out of the box, since Bulma has no JavaScript and you must supply it
- Projects that must support Internet Explorer fully, since the README says IE 10+ is only partially supported
- Teams that want a heavily opinionated design system with a fixed look, since much of the appearance is meant to be customized
Primer CSS
- New projects that need full component patterns: the README directs these to primer/react or primer/view_components, since this project is in KTLO (keep-the-lights-on) mode
- People who want a no-build, plain-CSS drop-in: the README says the source is Sass using SCSS syntax, so a build step is expected
Trade-offs
Bulma
- Browser support is limited to recent versions of major browsers, with only partial support for IE 10+
- Interactive behavior must be written or added separately
- The README notes the project is in constant development, so details may change between releases
Primer CSS
- The README states the project is in KTLO (keep-the-lights-on) mode, so new development is limited
- Requires a Sass toolchain and knowledge of load paths
- The README is brief on specifics, so details such as browser support and configuration are not covered here
Getting started
Bulma
Install with npm
npm install bulmaInstall with Yarn
yarn add bulmaPrimer CSS
Install the package
npm install --save @primer/cssFrequently asked questions
What is the difference between Bulma and Primer CSS?
Bulma: A CSS framework built on Flexbox that gives you styled layout and UI classes. Primer CSS: GitHub's CSS design system, distributed as Sass styles for building GitHub-style interfaces. Bulma suits developers who want a quick, consistent styling baseline for a web page, while Primer CSS suits developers who want to match github's visual style in an existing web project.
Are Bulma and Primer CSS free?
Bulma: Free and open source. Primer CSS: Free and open source.
Which is easier to set up, Bulma or Primer CSS?
Bulma is easier to get started with (rated beginner); Primer CSS is rated intermediate and usually needs more setup.
Is Bulma or Primer CSS more popular?
Bulma has more GitHub stars (50k) than Primer CSS (13.1k). Popularity isn't the same as fit — check which one matches your use case above.
What are other alternatives to Bulma and Primer CSS?
Other options people compare them with include Bootstrap, Tailwind CSS, Milligram, Spectre.css, Materialize.
Keep comparing
Built from our catalogue entries for both products: open-source details come from each project's README (AI-assisted, refreshed weekly) and GitHub data; AI-tool details are editorial. Spotted something wrong? Let us know from either product's page.