I want a custom webkit-scrollbar to animate a different background color for the hover state. The code below changes the color on hover but doesn't animate anything. It works on a div so I suspect webkit-scrollbar doesn't play nice with transitions.

::-webkit-scrollbar-thumb {
    background-color: #a8a8a8;
    -webkit-transition: background-color 1s linear;
}

::-webkit-scrollbar-thumb:hover {
    background-color: #f6f6f6;
}