button-icon.css

/* Change the main color accentuation when hovering buttons */
@media (hover: hover) and (pointer: fine) {

    /* Remove background when hovering for all buttons except for the ones inside a .listItem and the "Play" button on cards */
    :not(.listItem) > .paper-icon-button-light:hover:not(:disabled):not([data-action="resume"]) {
        color: rgba(255, 255, 255, 1);
        background-color: transparent;
    }

    /* Change background color for buttons in a .listItem*/
    .listItem>button {
        border: 1px dashed transparent;
        transition: none;
    }

    /* Change background color for buttons in a .listItem*/
    .listItem > button:hover {
        color: rgba(255, 255, 255, 1) !important;
        background-color: transparent !important;
        border-color: white;
        border-radius: 0.9em;
        transition: none;
    }

    /* Increase font size (of the icon) when hovering certain buttons */
    /* .emby-input-iconbutton:hover,
    .btnCardOptions:hover,
    .btnOptions:hover,
    .btnUserMenu:hover,
    .btnCardMenu:hover,
    .btnDeviceMenu:hover,
    .emby-select-iconbutton:hover {

        .material-icons {
            font-weight: 900;
        }
    } */

    /* Also change color when hovering the "More" button in detail page (it does not have class .paper-icon-button-light) */
    .button-flat.detailButton:hover {
        color: rgba(255, 255, 255, 1);
    }
}