.post-info {
    ..
    ..
    opacity: 0;
    transform: translate3d(0,0,0);
    transition: all 0.3s ease; /* can't add specific property because it ignores the other one */
}

.active .post-info {
    opacity: 1; /* When post is active (slider), show the post-info */
}

.post-info:hover {
    transform: translate3d(0,15px,0); /* When I hover the post-info, make it go up a bit */
}

.post-info {
    ..
    ..
    opacity: 0;
    transition: opacity 0.3s ease;

    transform: translate3d(0,0,0);
    transition: transform 0.5s ease-in;
}