Invalid decimal literal error that isn't actually an error

[WorkOLS]

So I'm trying to use VS Codium, and I know I must be doing something wrong. I've been going through different text programs, all of which seem to work in Notepad++, but not when run with VS Codium. Here is the code:

And here is the error:

As you can see, "640px" is a perfectly valid CSS number. Note also that the specific code doesn't matter. If I were to backspace over this line, the error would simply move to the next number. If I enter different code into VS Codium, the error persists. Clearly this is something wrong with the IDE, but I have no idea how to fix it. What do I do?

Note: I am a noob. Please answer this question as you would a 10 year old.

[daiyam]

Please answer this question as you would a 10 year old.

Ask your mom. 😉

It's an error from one of your installed extensions. Without any extensions, I can't reproduce the issue.
Maybe a linter?

Try the command > Help: Start Extension Bisect

[WorkOLS]

Okay, where do I write that command?

[daiyam]

Ctrl+Shift+P then Help: Start Extension Bisect