Dark Green usually means: The mod is compatible with the version that you are playing, but it could have some bugs or visual bugs.
- Is it compatible?
- Yes.
- Is it safe to play with?
- Yes.
- Will the mod work properly?
- This one I could not answer. But mostly, yes.
- What if you are playing and find out that the mods are bugging and causing the problem?
- Uninstall every mod > then try reinstalling each mod one by one > See which mod causes the game to bug or crash. (But Dark Green Mods are very unlikely to be broken and have the potential to break the game.)