I was poking at this today, playing with some colors, and I found what I think is a problem.

#archive-month .month { background-color: $*color_entry_background; }

#archive-year .month .header h3 { background-color: $*color_entry_title_background;
color: $*color_entry_title;
border-bottom: 1px solid $*color_primary_background;
padding: .20em .25em;
margin: 0; }

Works fine if the color_entry_title and color_entry_background are different, but is unreadable if they're the same (like they are for me). I can kludge it in my already-kludged version of this XD, but I thought I should point it out for patching.