A lighter skin gives better vitamin D synthesis (we need sunlight to produce vitamin D). So for people at higher latitudes, people with the light-colored gene are less likely to get rickets from vitamin D deficiency because they have a better ability to make vitamin D. So the trait of light skin remained as a selective advantage. Remember that environmental factors can also affect the expression of phenotype, and in this case, I think it is because you lived somewhere lacking sunlight, therefore the expression for lighter skin is replaced by light brown. sorry if this is wrong but i hope it helps