Pseudo-elements in CSS are not really well known. A feature from before 2011, but yet, front-end developers don't know how to unleash their powers.
In these slides prepared for Luxembourg JS (meetup - demo) and DevFest / GDG Nantes (workshop) you will find demonstrations and exercises to practice your pseudo-elements skills.
If you want me to facilitate this Workshop, contact me on Twitter. (info in the slides deck)
I won’t hide it to you: the excercises need a facilitator with high skills in CSS.