Net.Like.Xue.Tokyo/Assets/BITKit/Unity/UX/SubMenu.uss

Button {
    background-color: rgba(0, 0, 0, 0);
    border-left-width: 0;
    border-right-width: 0;
    border-top-width: 0;
    border-bottom-width: 0;
}

Button:hover {
    background-color: rgb(64, 64, 64);
}

Button:active {
    background-color: rgb(125, 125, 125);
    color: rgb(29, 29, 29);
}