Is Figma a CSS framework?
Figma is a tool for graphic designers. It's considered the industry standard and it currently offers a freemium model.
No, figma is not a CSS framework. Although you are able to export and use CSS code generated from your design layers and wireframes. Unfortunately besides the color codes, gradients and some shadows - everything else is pretty useless because your css positions the layers absolute which makes you design non responsive for smaller resolution devices.
If you're looking for CSS frameworks you can look into Bootstrap, Tailwind CSS or Bulma. Or you can use a lightweight framework called Pure CSS.
As for Figma, it's a tool for UI/UX designers, it doesn't really offer frameworks and libraries for front-end developers. There are a few plugins that try to convert design to code but they are broken and there is really no decent nor working solution at the moment.
What is a CSS Framework?
A CSS framework is a pre-prepared library of code that is designed to allow for easier, more standards-compliant styling of web pages using the Cascading Style Sheets language. It can provide a more structured approach to styling a webpage, allowing for faster development times and easier maintenance. Popular CSS frameworks include Bootstrap and Foundation.