Figure changes for print version

[juliasilge]

Closes #215

This PR (which we will not merge into the main branch) contains the rest of the figure changes for printing in grayscale. I found more changes that I do want to integrate into the website so I'll do another PR, merge it, and merge main back into this branch after we make some of the other changes.

Still to be done are the figures outlined in #212; some of those should go into the main branch and some shouldn't.