In Finnish language we have three words for pink. Vaaleanpunainen, pinkki and roosa. :D I think that vaaleanpunainen is the most used of these words and roosa is the least used. Well, some Finns may say that there is a slight difference between these colors but they are all same to me. :) By the way, literal translation for vaaleanpunainen is light red.
"Vaaleanpunainen" seems so cumbersome. I'm surprised that "roosa" isn't more commonly used.
Understandably, given the trousers vs pants situation in the US vs UK.
byxor really only means 'pants' as in e.g. jeans.
'underwear' is underkläder in general, specifically trosor for women and kalsonger for men; underbyxor is 'underpants' but usually only used about women's underpants, I think. On the other hand långkalsonger 'long johns' are gender neutral, that's the kind of long underwear people use when it's cold, regardless of gender.
And then there's all sorts of briefs, boxers, leggings and tights and hotpants and what not, that I hope are the same as their English namesakes. :)