Can you mix a transformation with an animation?

Question

Hi, I really want to make this css code work to its best. I am trying to make the yellow and white stars grow bigger and smaller again, and loop, but I cant seem to figure it out. Is it possible!!?? And if so, how can you do it???
This is my code:

https://code.sololearn.com/Wz0MMd6TNHaO/?ref=app
Thank you if you do

Answer 1

https://code.sololearn.com/WTCtbSmB6OBJ/?ref=app

Answer 2

https://code.sololearn.com/WNvYB6k7zr9b/?ref=app

Answer 3

r8w9 and Kougaiji-sama, thanks for all your help, I have managed to combine both of yours together, and I have finished it. Have a look if you want to

Answer 4

beautiful!