W3c is the body that tries to standardize these things, they produce The foundations, then programmers produce their rendering engine to interpret These guidelines. Here's some code which i a short while ago wrote. I imagine that it offers a standard clarification of mixing class/ID names with pseudoclasses. Is * https://hotbookmarkings.com/story19386095/prestashop-seo-redirections-of-pages-management-an-overview