.hideable {
    -moz-animation: cssAnimation 0s ease-in 10s forwards;
    /* Firefox */
    -webkit-animation: cssAnimation 0s ease-in 10s forwards;
    /* Safari and Chrome */
    -o-animation: cssAnimation 0s ease-in 10s forwards;
    /* Opera */
    animation: cssAnimation 0s ease-in 10s forwards;
    -webkit-animation-fill-mode: forwards;
    animation-fill-mode: forwards;
}
@keyframes cssAnimation {
    to {
        width:0;
        height:0;
        overflow:hidden;
    }
}
@-webkit-keyframes cssAnimation {
    to {
        width:0;
        height:0;
        visibility:hidden;
    }
}
.ui.menu.custom {
    border-radius: 0 !important;
}
