Like many things, CSS is easy to pick up and hard to master. There's any number of reasons the author might not support mobile for this personal, free project.

Like many things, CSS is easy to pick up and hard to master. There's any number of reasons the author might not support mobile for this personal, free project. "I don't feel like it" would be a perfectly valid one. Also, based on their GitHub profile, they already have a job (at Google).