For example, Bootstrap, Bulma, Foundation, Semantic UI, PureCSS, Materialize these, I call it traditional CSS frameworks, usually these frameworks are used for rapid development of Web applications, more popular in the JQuery era. The disadvantages are also obvious. If your interface has a lot of custom designs, it will be painful to use. Fower is not a traditional CSS framework.
For example, Ant-design, Material-UI, Vuetify, React-Bootstrap, these UI Frameworks are created with the component era, and are often binded with some Front-end frameworks (React, Vue, Angular). Similarly, Fower is not an UI framework.
Some methodology for writing CSS, I think you should know it. They make a fuss on the principle of "separation of Concerns". This is the biggest difference between Fower and them. Fower does not advocate "separation of Concerns"
CSS in JS was developed by the React community. What is it? Long story shor, it is to use JS to write CSS. Popular solutions include Styled Components, Emotion, JSS, Radium, etc. Fower also is a solution of CSS in JS what's the difference? The difference is that Fower uses the "Atomic props" method to write style, the concept is similar to "Atomic CSS".
The atomic CSS is a non-traditional CSS solution, And I like it very much. Fower also uses this concept. But the difference is that they are writing CSS, while Fower is writing JS.
In fact, you can understand Fower as "Atomic CSS" + "CSS in JS", which I call "Atomic Props".