From livejournal's 11_reasons community, theme table 3, prompt #25 color.
Everything about Hogwarts is dark. Black wool uniforms, grey stone walls, rusted metal sconces. There is nothing really bright or cheery about the happy wizarding school, except from the outstanding professors and generally good attitude of the students.
Oliver thinks that color doesn't seem to matter when the environment is so positive, but then he thinks of Rachel.
The American girl who always accessorizes with bright neon, and deep gold's, and rich reds to accentuate her uniform and whatever else she happens to be wearing. But Rachel isn't bright. She is intelligent, in her own way, but her outlook is bleak. Oliver doesn't know all of her story, but he knows enough to know that she's not proud of the mistakes that she's made, and they haunt her now, nearly six thousand kilometers from her home. He wonders what it is exactly that she ran away from, because she won't admit it, but he knows that's what she did, and he knows that the colors that she wears are just her way of attempting to remain bright.