there's a bunch and the story is huge so i don't blame u. ofc i'm not going to talk about every single one of them since i want people to find and think about it (sometimes people identify things that i didn't even think about lol). i think the obvious ones are the elements of nature and how each element affects each other water is love basically, air is something pure, always around and always coming and going but never going away. fire is desire and danger and fear. electricity is epiphany etc etc. another one i can think about are lily and haewon with the color red. another one is during ch 11 where bae and haewon use those pfp on twt where haewon is yellow and bae is purple, when bae's favorite color is yellow. that shows how bae always abdicates and purple is yellow's opposite color so it reflects their confused feelings for each other and how bae lives in haewon's shadow