Can someone please tell me if it is possible style css like for e.g. p::before and p::after? And how to do that?

I experimented with this some time ago, and despaired of doing it via the Pseudo Classes etc. available in the Element States Selector in the Styles panel. Implementation via styling in the Settings Head section as in this SD V3 project file seems quick and easy.

Frank

PS. I used the single colon version for compatibility with IE 11