Bulma is an open-source CSS framework built on Flexbox that provides a responsive grid, typography, form controls, navigation, layouts and a set of interface components expressed entirely through HTML classes. The official site contains the documentation, getting-started instructions, customization guide, component reference, examples, migration notes and links to the source repository and community resources. It is distributed as plain CSS or Sass source and does not ship its own behaviour layer, so interactive elements such as dropdowns or modals are wired up by the developer.
The documentation is arranged around columns, layout, form elements, components, modifiers, helpers and customization. It explains the container and column syntax, breakpoint names for mobile, tablet, desktop and wide screens, and the is-primary, is-large or is-centered modifier pattern applied consistently across buttons, tags, notifications and cards. The customization chapter covers Sass variables, derived color palettes, spacing scales and how to build a reduced stylesheet with only the modules a project needs, while the examples show complete page skeletons that can be adapted directly.
It suits developers building admin panels, documentation pages, marketing sites or prototypes who prefer readable class names over writing layout CSS from scratch, and teams that want a consistent visual baseline without adopting a component runtime. Designers can use the modifier system to keep spacing and color decisions uniform, and students learning responsive layout can inspect the column rules to understand how Flexbox breakpoints behave in practice.
Compared with utility-first frameworks, Bulma offers named components that are quick to assemble but less granular when a design departs from the defaults. Compared with full JavaScript component libraries, it is lighter and framework agnostic, yet it leaves state, focus management and accessibility behaviour to the implementer. Compared with hand-written CSS, it saves repetitive work on grids and forms, at the cost of shipping a stylesheet whose unused parts should be trimmed before production.
Check the major version before following a tutorial, because class names and Sass variables have changed between releases. Review the compiled file size and import only the needed Sass modules for production, and pair the framework with an accessibility review for menus, dialogs and form labels. Since Bulma supplies no interactivity, keyboard handling and ARIA attributes remain the responsibility of the developer.