Ah sorry you are right. But font-family will work the same in this case. font is a shorthand for font-family, font-size and others.

Using font means that you don't need to specify everything to just even change the size, or in this case, font

True. You can specify the name of the font, the size, the weight etc. all in one line.

I think the OP is referring to the article headings, since there's the following bit in Wikia.css and the mentioned font isn't working for them:

.WikiaArticle h2 {
   font-family: 'M PLUS Rounded 1c';
   border-bottom:1px solid #4f518f;
   margin-bottom:0.5em;
   margin-top:20px;
}
.WikiaArticle h3 {
   font-weight: normal;
   font-family: 'M PLUS Rounded 1c';
   color: #543399;
}
.WikiaArticle h4 {
   font-family: 'M PLUS Rounded 1c';
}
.WikiaArticle h5 {
   font-family: 'M PLUS Rounded 1c';
}

It looks like the font import isn't working for some reason, and I'm not sure why since everything looks fine with it to me...

Ah I missed that. I think the imprt is missing &display=swap which is part of the URL in the Google fonts page the OP linked to.

Nevermind, that's not the problem. The problem is that there is CSS code on both Common.css and Wikia.css so all the imports must be at the top of Common.css . Imports on Wikia.css will be ignored because they are not on the top of those two when combined together.

@HumansCanWinElves So, I should add my font imports to common.css instead?

It worked!! Thanks! tbh, i totally forgot I even used common.css. Lol

Thanks you guys. :D

Fandom prioritizes Wikia.css, but it still loads common.css ^_~

Common.css is part of the MediaWiki software. But yes it may be better to put everything just on Wikia.css and leave Common.css blank.