/*transitions.css*/

a:link {
    transition: color 0.5s;
}

img{
    opacity: 0.15;
    transition: opacity 500ms;
    position: absolute;
    scale: 50%;
}
.visible{
    opacity: 100;
}

img:hover{
    opacity: 1;
}

/*challenge*/

figure.visible{
    opacity: 1;
}

figure.hidden{
    opacity: 0;
}