OP has a valid point. On my Mac, it's unreadable without zooming in. I immediately left the page.

Thanks for the valuable feedback. I've added a mediaquery for your use case. This should be more legible now: https://lukeb42.github.io/vertex-manual.html

Send me a screenshot via https://catbox.moe if it's unreadable and I'll get this done and dusted before leaving the thread. Thanks.