pseudo elements CSS psuedo-elements pseudo elements CSS Tricks :before https://css-tricks.com/almanac/selectors/a/after-and-before/ agregándolo desde CSS CSS pseudo element CSS Tricks CSS ::after selector CSS-Tricks CSS Pseudo-elements before/after agregándolo desde CSS agregándolo desde CSS psuedo elements psuedo elements :after pseudo element :before and :after Pseudo Elements ::before and ::after CSS-Tricks ::before and ::after :before and :after