app.css

body {
  background: #22222f;
  padding-top: 1em;
  color: #eee;
}

a, a:hover {
  cursor: pointer;
  color: #eee;
}

.base-dir-icon {
  cursor: pointer;
  vertical-align: middle;
  margin-right: .125em;
}

.browser-view {
  margin-top: 3em;
}

.browser-view a {
  cursor: pointer;
  background-color: #333344;
  color: white;
  padding: 1.5em 3em 1.5em 1.5em;
  margin: .5em;
  min-width: 15em;
  display: inline-block;
  border-radius: .25em;
}

.browser-view a span {
  margin-right: .66em;
}

.browser-view a:hover {
  text-decoration: none;
  transition: background-color .25s;
  background: #434354;
}

.bg-translucent {
  display: none;
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  background: rgba(0, 0, 0, 0.5);;
  cursor: pointer;
}

.file-view-wrapper {
  display: none;
  position: absolute;
  top: 10%;
  right: 10%;
  bottom: 10%;
  left: 10%;
  min-width: 10%;
  background: rgba(0, 0, 0, 0.5);;
  transition: width 200ms, height 200ms, left 200ms;
  text-align: center;
}

.file-view-img {
  max-width: 100%;
  max-height: 100%;
  box-shadow: 0 0 3em black;
}

.file-view-prev, .file-view-next {
  display: none;
  position: absolute;
  top: 43%;
  cursor: pointer;
  opacity: .8;
}

.file-view-prev {
  left: .75em;
}

.file-view-next {
  right: .75em;
}

.file-view-prev:hover, .file-view-next:hover {
  opacity: 1;
}