implement GWERN style principles

Have a look at this site and see what elements might make sense to up the quality of the Heartbeat Setup: https://www.gwern.net/Design#principles
Here are some oof the principles:

• visual differences should be semantic differences
• UI elements that can react should change on hover
• all UI elements should have tooltips/​summaries
• hierarchies & progressions should come in cycles of 3 (eg. bold > smallcaps > italics)
• all numbers should be 0, 1, or ∞
• function > form
• more > less
• self-contained > fragmented
• convention (linters/​checkers) > constraints
• hypertext is a great idea, we should try that!
• local > remote—every link dies someday
• archives are expensive short-term but cheap long-term
  reader > author
• give the reader agency
• speed is the 2nd-most important feature after correctness
• always bet on text
• earn your ornaments
• if you go overboard on minimalism, you may barely be mediocre
  “users won’t tell you when it’s broken”
• UI consistency is underrated
• when in doubt, copy Wikipedia
• if you find yourself ⁠doing something 3 times⁠, fix it.