@keyframes slide-in {
    from { margin-left: 50px; }
    to { margin-left: 25px; }
}
.slide-in {
    animation-name: slide-in;
    animation-fill-mode: both;
    animation-duration: .25s;
    animation-timing-function: ease-in;
}

@keyframes slide-out {
    from { margin-left: 25px; }
    to { margin-left: 50px; }
}
.slide-out {
    animation-name: slide-out;
    animation-fill-mode: both;
    animation-duration: .25s;
    animation-timing-function: ease-out;
}