.portfolio-sections{
    display: grid;
    text-align: center;
}
.ptile {
    height: 14rem;
    min-width: 14rem;
    display: flex;
    flex-direction: column;
    justify-content: center;
}
.tile1 .artlinks, .tile2 .artlinks{
    display: block;
    height: 0px;
    transition: height 200ms ease-in-out;
    overflow: hidden;
}
.tile1:hover .artlinks, .tile2:hover .artlinks{
    height: 1.3rem;
}
.tile1 .artlinks a, .tile2 .artlinks a{
    margin: 0 1rem;
}
.tile1 {
    grid-column-start: 1;
    border-right: 3px solid #50E3C2;
    border-bottom: 3px solid #50E3C2;
}
.tile2 {
    grid-column-start: 2;
    border-bottom: 3px solid #50E3C2;
}
.tile3 {
    position: relative;
    grid-column-start: 1;
    grid-row-start: 2;
    border-right: 3px solid #50E3C2;
}
.tile3 .github, .tile4 .bitbucket{
    position: absolute;
    top: 46%;
    left: 50%;
    transform: translate(-50%);
}
.tile3 .artlinks img, .tile4 .artlinks img{
    opacity: 0;
    transition: opacity 500ms;
}
.tile3:hover .artlinks img, .tile4:hover .artlinks img{
    opacity: 0.4;
}
.tile4 {
    position: relative;
    grid-column-start: 2;
    grid-row-start: 2;
}
.tile3 a:hover,.tile3 a:focus,.tile3 a:active, .tile3 a:visited, .tile3 a, 
.tile4 a:hover,.tile4 a:focus,.tile4 a:active, .tile4 a:visited, .tile4 a{
    text-decoration: none;
    color: inherit;
}