me, an intellectual: clothing is an important part of showing how a character feels and it’s incredibly important that how they look on the outside matches what they feel internally. lukas has finally accepted himself and is not afraid to show who he is. him wearing a shirt with an alarming color like that shows that he has changed, he is not the same anymore. the shirt is so unusual from what we’ve seen him wear before which i’m sure everyone noticed, meaning that we are not supposed to be used to this new version of him, we’re supposed to feel like he has changed a lot. lukas talking openly about kissing philip in front of everyone would not be as convincing if he wore one of his standard plaid shirts, as that would make us doubt that he actually means what he says. now, with this new unfamiliar look to him we believe him and we’re now understanding how much he’s changed.
the color of the shirt was done deliberately too. the color green resembles three very important things; growth, safety, and self love/self acceptance. lukas has grown so much and has finally reached the end of his arc, this version of him is the complete version. and he is finally safe now that ryan is dead and now that lukas has realized that no one would hate him for who he is. most importantly he has started accepting himself and is safe in his own skin. the shirt is almost looks yellow sometimes too, and with the stark blue colors on some parts of the shirt these three colors form together a feeling of hope, meaning that lukas has a bright future ahead of him. this is to emphasize the shot of them running off into the sunset together, which is a metaphor for moving onto a better life.
lastly, it matches the analogous color scheme of the scene perfectly. that same green color can be found on lukas’ bike and on the trees around them. green is clearly the dominant color of the scene, making everything green seem natural. this makes you feel like lukas belongs here. as i said earlier this is a color we never see lukas in, but making him blend in with the colors of the scene makes us think this is the right color for him, meaning this new lukas, this open and happy lukas, is the “right” version of him.