.photogrid {
    display:flex;
    flex-direction:row;
    flex-wrap:wrap;
    align-items:center;
    justify-content:center;
    width:80%;
    margin:0 auto;
}
.photogrid img {
     width: 200px;
     height: 200px;
     margin:5px;
     opacity:1;
     transition: opacity 0.5s ease-in-out;
     cursor:pointer;
     z-index:1;
}
.photogrid img:hover {
     opacity:0.5;
}
button.close-button {
    background:#fff;
    padding:0 8px;
    top:1.5em;
    right:1.5em;
    border:solid 2px rgba(0,0,0,0.4);
    border-radius:40px;
    font-size:1em;
}