CSS stands for Cascading Style Sheets, which is a plural phrase. One would say:
Cascading Style Sheets are used to provide a central location for all of the stylings of a project.
However, it seems to be the prevalent usage to say:
CSS is used to provide a central location for all of the stylings of a project.
Why do we do this, and is this correct? Would anyone ever say "CSS are used to provide a central location for all of the stylings of a project"?
Best Answer
CSS here has evolved as a noun independent as to what it means as an acronym. It refers not just to "cascading style sheets" themselves, but to the entire system and infrastructure for styling web pages.
In short, it is a singular noun that has come into existence due to common use.
Here is a similar example: Imagine a company called "Unlimited Designs." judging by the name, you might say something like "Unlimited Designs is going out of business." It's a singular noun, even though designs is plural.