html, body {
  margin: 0;
  font-family: sans-serif;
  height: 100%;
}

.app {
  height: 100%;
  width: 100%;
  display: flex;
  flex-direction: column;
}

.header {
  text-align: center;
  padding: 20px 0;
}

.header h1 {
  margin: 0 0 10px 0;
}

.header select {
  font-size: 1rem;
}

.slideshow {
  flex: 1;
  background-color: #333;
  position: relative;
  overflow: hidden;
}

.slide {
  position: absolute;
  top: 0;
  bottom: 0;
  left: 0;
  right: 0;
  background-repeat: no-repeat;
  background-size: contain;
  background-position: center center;
  opacity: 0;
  transform: scale(1);
  transition: all .9s ease-out;
}

.slide:nth-last-child(2) {
  opacity: 1;
  transform: scale(1.08);
}