The bronze and gold achievement badge are really hard to distinguish for the Red-Green-Colourblind (at least my type of it).
This could be fixed with a colour adjustment (bronze darker, gold lighter for contrast), but – if this is a simple texture – adding a sheen to the gold badge could already suffice, a border could also work. Another robust way to fix this for all people is to add a popup that tells you the grade when you hover over it.

The bronze and gold achievement badge are really hard to distinguish for the Red-Green-Colourblind (at least my type of it).
This could be fixed with a colour adjustment (bronze darker, gold lighter for contrast), but – if this is a simple texture – adding a sheen to the gold badge could already suffice, a border could also work. Another robust way to fix this for all people is to add a popup that tells you the grade when you hover over it.