CSS problem

Question

So i wrote this code after experimenting for 3 hours
And the problem is : i don't know how to code it so the heart will beat and the background will be red and the text will appear just by hovering over the heart, how can i do that?
And second question:
What is the difference between position: relative, position: absolute and position: fixed?
I got it after experiencing for to hours ☺

https://code.sololearn.com/WpxVaI9o7Kx1/?ref=app