I’m a child please make responses more clear
As clear as I can be:
yellow - yes, if it's bright yellow.
brown - no
white - no (you will find BBgunz4U stylee sellers flogging white guns without a defence, they shouldn't be)
Cat pad (apple green) - yes if it's bright green.
bright green woodland camouflage - yes if more than half the gun is bright green
multicam arid - no
multicam tropic - no
leaved with bright colours - yes, if more than half the gun is bright red, orange, blue, yellow, green, pink or purple.
multicam snow - no
and is it legal to have just a two tone stock with a military colour weapon - no, as it won't be more than half the surface area of the gun. Stock plus handguard is the usual combination.
Additionally:
If you're under 18, you can't legally buy any imitation firearm, realistic or otherwise. Neither can it be bought on your behalf. It can be gifted to you.
If you've somehow got your hands on a realistic imitation firearm, you do not, strictly speaking, have to make it unrealistic. However, it wouldn't be the worst idea to do so if you're under 18.
If you're intending to use it at an airsoft skirmish site, nobody there will care about whether it's realistic or not, or how you got it.
If you're intending to use it for any other purpose than airsoft skirmishing or plinking on your own private, secluded land, please don't, for your sake and ours.