The recommended font is Monaco font-family: Monaco, Consolas, Menlo, monospace
and UI theme https://atom.io/themes/pristine-ui
You can install Fleko Syntax via Atom in Preferences > Install (themes tab)
and search for Fleko Syntax
Or via command line $ apm install fleko-syntax
Good catch. Let us know what about this package looks wrong to you, and we'll investigate right away.