Why doesn't background work?

Question

css

Answer 1

In general, the link is beating?
In the meantime, it seems for :before you need to set the width and height and check.
Or set: background-size: 100% 100%;

Answer 2

I found the answer to my own question! It turns out I forgot to set display: inline-block; and the image did not appear because of this. And thanks to the person who said to register the dimensions. So I would not know what to do further.