colophon
The final bit of the document is not inside a columned content. there fore, the text get very long line.
we tend to believe latin text is best readable when it’s line length is between 55 and 65 characters per line.
you can hide the title “colophon” and put the whole content (the coko logo, and the bit of text) at the bottom of the page using position absolute. This way it looks like the final piece of the book
also, you can remove the running head.