How to Style `a:before` with `:hover` and `:visited` Pseudo-classes?

Addressing the Invocation of 'a:before' With ':hover' and ':visited' Conditions

The inability to successfully utilize 'a:before:hover' stems from a fundamental understanding of CSS syntax. To properly apply styles to a 'a:before' pseudo-element when an 'a' element matches a pseudo-class, the format should be 'a:hover:before' or 'a:visited:before'. This signifies that the pseudo-element comes after the pseudo-class in the selector.

In CSS3, the use of double colons (e.g., 'a:hover::before' or 'a:visited::before') enhances clarity in distinguishing pseudo-classes from pseudo-elements. However, single colons are adequate for legacy browsers like IE8 and below.

The order of pseudo-classes and pseudo-elements is strictly defined in the specification. A pseudo-element can only be appended to the end of a simple selector sequence, which is a chain of selectors without combinators. A simple selector includes type selectors, universal selectors, attribute selectors, class selectors, ID selectors, and pseudo-classes. While pseudo-classes are simple selectors, pseudo-elements are not.

However, for user-action pseudo-classes like ':hover', if the desired effect is restricted to user interaction with the pseudo-element, it is currently not feasible through standard CSS. Instead, ':hover' must be applied to an actual child element.

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