The styles for this template come from Template:Color/styles.css. The light/dark mode specific elements are defined in MediaWiki:Citizen.css.
examples
{{BalanceBadge|new|new}}
- new
{{BalanceBadge|removed|removed}}
- removed
{{BalanceBadge|reworked|reworked}}
- reworked
{{BalanceBadge|buff|buff}}
- buff
{{BalanceBadge|nerf|nerf}}
- nerf
The above documentation is transcluded from Template:BalanceBadge/doc. (edit | history)