DECSS (pronounced /decks/ or /dee-ee-CSS/) is neither a CSS module like Tailwind CSS nor a CSS methodology like BEM. DECSS is a term coined to describe a philosophy about the Definitive Ecosystem of CSS. In short, DECSS is a kind of treatise on what CSS should be. Since I, the author, am Japanese, so other pages will be written in Japanese only.

In a nutshell, what DECSS wants to consider is whether we should use Utility-First CSS like Tailwind CSS.

My definitive theory is that whether to design with semantic CSS or utility-first CSS is a matter of preference, not a matter of which is better.

I am Japanese and eat Japanese food on a daily basis. But I also eat Italian food, and pasta is one of my favorites. If you were to go to a restaurant with me, and I were to order pasta instead of Japanese food, you would not advise me that "You should eat Japanese food". It's the same thing. If someone is trying to use Tailwind CSS, you have no right to advise them that "It is not good and you should use semantic CSS design".

This is a matter of taste. Both Japanese and Italian food are wonderful, and if you keep eating the same thing, on the other hand, you may eventually stop wanting to eat it. If that happens, you can always try something else. Comparing Japanese and Italian food is nonsense. You only need to consider whether what you want to eat is to the liking of that "development project" or not.

... However, you may not know for which projects semantic CSS design or utility-first CSS design is appropriate. Let's take a closer look at each of these and other CSS design techniques.