I’ve updated Tiny Theme for Micro.blog with a few quick changes & bug fixes. Improved blockquotes, fixed horizontal scroll bug, added accessibility improvements, improved link styling, added pagination to category pages, & fixed alt text for logo. You can upgrade to 1.0.5 on the plugins page.
@numericcitizen My suggestion to learn is use one of the basic themes (such as the default one or Marfa or even Tiny) and start small. Tweak the color and font-size. Move the date to the bottom of a post. Center the header. Stuff like that. You can manipulate these themes into almost anything you want using only CSS and very minor custom theme edits. When you nail that, you can go full custom if you still have the need.