Menu hamburger color

My website is http://utopianediting.com. Currently, on both mobile and tablet, the menu “hamburger” is white against a white background. It’s there and clickable, but a visitor wouldn’t know that.

Also, the “back to top” arrow is present but white, which means it doesn’t show up except against the gray of the footer (see attached screenshot).

Both were black up until a couple of days ago. I don’t know if my web developer accidentally changed it, but I’ve already ended the contract and paid. I need to fix it in a hurry because I already started promoting my site (before I noticed the problem).

How can I change the color of both back to black?

Thanks.