There is some issues with quotes for some reason in magazine styling. I have had to eliminate them entirely in some cases for it to work. For example, instead of this which would be correct (this changes the mag title font, btw):
section.magazine.section h4 { font-family: "DM Serif Display"; }
I had to eliminate the quotes and use this for it to work:
section.magazine.section h4 { font-family: DM Serif Display; }
And for adding a background image to your mag, instead of this, which would be correct usually:
#middle { background: url('imageURLhere'); }
You must do this in order for it to work:
#middle { background: url(imageURLhere); }