This is pretty minor, but my book collage is displaying kind of funny, probably because I have too many books.
On browser (Firefox) it starts at 8 columns across, but the eighth column is half off the screen. I get a scroll bar that lets me scroll right to bring it fully on screen. As I scroll down, the columns stop populating until there are four columns with a column space between them at the bottom.
On mobile (android app), It does the same thing, but with the four right columns off screen.