Clean up SVG header output
Simplify `font-family`

`font-family: Arial, Helvetica, sans-serif` doesn’t make a lot of sense, as all systems that have Helvetica included have Arial too (i.e. Helvetica would never be used). By simply using `sans-serif`, Helvetica is used where available, with Arial as the fallback.
Consistently use lowercase for hex digits
Use <style>
Use original font-family stack

Have intentionally chosen Arial for these badges :)
update badges
update .gitignore