Yellow background on all headings


I am working on a new site at

After successfully changing the color and font of the headers everything was looking good.

Suddenly any new header has a yellow background. At the same time this happened, the yellow arros that scroll to the top became square and lost their style.

How can I reverse this? How did it happen?

I granted access so you cna take a look…. and have no plugins activated yet. This is anew site.