Over at CSS { In Real Life }, author Michelle Barker has detailed a clever way to style pseudo-elements (such as ::before and ::after) through JavaScript.
In Javascript we have a few ways of selecting elements, but we can’t directly target pseudo-elements. […] Luckily, CSS custom properties can help.
👉 If you set a custom property on the element that “owns” the pseudo-element the pseudo-element itself can pick it up, thus enabling a way to style it.
Quick Tip: Style Pseudo-elements with Javascript Using Custom Properties →