Why does gulp throw an error when compiling sass to css?

Question

css

Hello. I'm just starting my way in layout, so please don't kick me.
I'm drafting a project for a portfolio right now, everything is going well, everything is working out, but something strange happened yesterday. Out of the blue, gulp stopped compiling sass to css. Gives the following error:

Here is the code:

Stopped saving after 692 lines. I erased all the code before the media query, it doesn't save either. In general, no matter how you erase it, it still does not save and swears by this error always on the last line.
Here is js with gulp: