The font on mobile also looks different - instead of incredibly thin, it is too bold. I don't have any images or screenshots from how it looked like before. I'll put the custom CSS I have below just in case. I do have custom CSS, but it's been the same for a while and I didn't update anything before the mysterious change in font. Bolding no longer works on the website for Helvetica Neue, either.
I cannot get it back to the way it was for the life of me and I'm not sure what went wrong. I'm assuming it has to deal with the font weight, but I didn't change anything nor add any custom CSS - it is set to 700. It was completely fine on Friday when I was also editing some things (not the design).
When I logged on today to make some small changes (not to the design), the font was incredibly thin. The Helvetica Neue font no longer looks the same on my website.