How to prevent sticky hover effects for buttons on touch devices

Since this part of CSS Media Queries Level 4 has now been widely implemented since 2018, you can use this:

@media (hover: hover) {
    button:hover {
        background-color: blue;
    }
}

Or in English: “If the browser supports proper/true/real/non-emulated hovering (e.g. has a mouse-like primary input device), then apply this style when buttons are hovered over.”

For browsers that do not have this implemented (or didn’t at the time of this original answer), I wrote a polyfill to deal with this. Using it, you can transform the above futuristic CSS into:

html.my-true-hover button:hover {
    background-color: blue;
}

(A variation on the .no-touch technique) And then using some client-side JavaScript from the same polyfill that detects support for hovering, you can toggle the presence of the my-true-hover class accordingly:

$(document).on('mq4hsChange', function (e) {
    $(document.documentElement).toggleClass('my-true-hover', e.trueHover);
});