Look how many different shades of green there are. My guess is these colors were added piece meal, one at a time. And it makes the overall look feel scattered. If we crafted a style guide, the color scheme (and other art) might look a little more unified.
Regarding the compounds colours, it might be the case that the same colour values are used in the GUI as the compound clouds use in the world. And those in-world colours have been tweaked for better visibility over the years. So there may be two choices: the GUI has different shades for the different compounds than in the game world, or the new GUI colours need to be picked to still have good visibility on the various backgrounds.
Just so I’m clear…are there more or less than 7 compounds planned to appear on the map as collectable clouds? If 7 or less, then the same color scheme could be used for the GUI as for the compounds (ROYGBV+White)…
If there are more than 7 compounds planned, I think color is the wrong way to differentiate them.
The new GUI colors would need to be picked to still have good visibility on the various backgrounds.
The background images should max out at a certain brightness. Then, the compound clouds will always have good contrast against them if we use the brighter colors for them.