@gabe It's notoriously hard to get 256 colours working nicely in Vim. Which terminal emulator are you using?
I use tmux inside iTerm and I've got this in my .vimrc:
let &t_8f="\e[38;2;%ld;%ld;%ldm"
let &t_8b="\e[48;2;%ld;%ld;%ldm"
set termguicolors
This is with Vim 8 (which improved 256 colour support, iirc).
@sahil I'm using gnome-terminal. I tried adding the lines you mentioned to my vimrc but it didn't seem to do anything.
I don't think it's an issue with the 256 colorspace, as the colors are displaying correctly, it just seems like the syntax highlighting rules are different in Vim than in Atom. Makes sense, I'm just totally lost as to how to make them the same.