Bulma
Bulma is a free, open-source CSS framework based on Flexbox for building responsive, mobile-first web interfaces. It provides a set of ready-to-use CSS classes for common UI components like buttons, forms, and navigation bars, without requiring JavaScript. The framework emphasizes simplicity, modularity, and customization through Sass variables.
Developers should learn Bulma when they need a lightweight, modern CSS framework to quickly prototype or build responsive websites without the complexity of larger frameworks like Bootstrap. It's ideal for projects where design flexibility and ease of use are priorities, such as personal websites, small business sites, or internal tools, as it reduces CSS boilerplate and integrates well with JavaScript frameworks like React or Vue.js.