How do I style my div’s so they are horizontally aligned instead of vertically aligned

Question

I AM MAKING aINtErACtiVe MENU BUT THe MENU ITEMS ARE VERTICALLY ALIGNED intESTEaD Of HoRRIZOnTAlly ALIGNED. HOW Do I FIX
https://code.sololearn.com/Ws012bdzX95G/?ref=app

PS - POST EDITOR IS GlITChED anD IT IS MAKING MY TEXT TOGGLE FROM CAPITAL To LoWERCASE.