/* transitions.css */

a:link {
  transition: color 0.5s;
}

img {
  opacity: 0.25;
  transition: opacity 500ms;
}

img:hover {
  opacity: 1;
}
/* challenge */

figure {
  position: relative;
}

figure img {
  position: absolute;
  top: 0;
  left: 0;
}

figure .visible {
  opacity: 1;
}

figure .hidden {
  opacity: 0;
}

figure:hover .hidden {
  opacity: 1;
}
figure:hover .visible {
  opacity: 0;
}