>>48807770If you must have an in-universe explanation then just consider it lipstick to match her outfit but
>>48807881 is mostly correct, it's 4 colors total like any other sprite: black, white(used as the transparency color on some sprite layers), and any 2 other colors which make a pallet and each sprite uses 1 pallet but more detailed images can be made by drawing multiple sprites together to look like one, the large trees for example are at least 2 sprites so the trunk and leaves can use 2 browns and 2 greens respectively to create shading and detail.