I am seeing that error message in the error console. But before chasing that down, you might want to correct other errors, just to see if this particular error is one of those "cascade" type errors. In other words, something else is wrong, something apparently unrelated, which then leads to this error.
I ran your CSS through a validator, and found a number of parse errors, along with a few instances of things like "font-weigt" (misspelled). The parse errors involved things like missing semi-colons, which can cause havoc in unexpected ways. I'd fix all of those, first.
Your HTML also fails validation, mostly for meta tags that it doesn't like.