css help

hii! ii'm a liittle stumped and need some help :}

-how do ii get my sections to shake? the biig maiin red boxes. iid liike to have the content shake as well, less iintensely. ii havve the code, ii just dont knoww wwhere ii should put iit.
https://i.ibb.co/px002x0/Screenshot-2021-04-23-10-17-37-AM.png
(^ aniimatiion code ^)

-ii cant get the flashiing text notiifiicatiion to showw up. iit wworks fiine wwiith my tiitle, but the other notiifiicatiion wwould just change the color pattern of the tiitle, or not showw up at all. wwhere wwould ii put the code to fiix thiis?

-ii havve some annoyiing rogue borders iim tryiing to fiix. all of the border, pattern, and margiin siizes are the same and wwork for evverythiing else.
https://i.ibb.co/SyXLTGq/oie-Toga3-EC6-Ob-Qt.png
(the border/paddiing[?] of the top friiends box, and profiile avvatar wwhen scrolled ovver iis too thiick. ii cant fiind any siize that diiffers from the others. also, the song player and the iinteractiion box has some wweiird, too-thiick double border.