._project_ {
    animation: opacityShow 0.5s linear;
    animation-fill-mode: forwards;
}

._project_._hidden_ {
    animation: opacityHide 0.5s linear;
    animation-fill-mode: forwards;
}

@keyframes opacityShow {
    0% {
        opacity: 0;
    }
    100% {
        opacity: 1;
    }
}

@keyframes opacityHide {
    0% {
        opacity: 1;
    }
    100% {
        opacity: 0;
    }
}