About ::before.

::before and ::after are psuedu classes In easy terms by this you can create more two objects from a single class hence total 3 objects from a single class, content:' '; is necessary to write https://code.sololearn.com/Wa7nNxqgs7Xz/?ref=app

Try first answer here: https://stackoverflow.com/questions/36197443/use-fontawesome-icon-inside-a-before-pseudo-element-with-attr

thank you