body {
  margin: 0;
  padding: 0;
}

#top-image {
  background: linear-gradient(  rgba(0, 0, 0, 0.2),  rgba(0, 0, 0, 0.2)  ), url('https://unsplash.it/2560/1080/?random') no-repeat fixed;
  position: fixed;
  top: 0;
  width: 100%;
  z-index: 0;
  height: 100%;
}

.jumbotron {
  background-color: transparent !important;
  color: white !important;
  text-shadow: 0 1px 2px rgba(0,0,0,0.15);
}

#content {
  width: 800px;
  transform: translateY(-50%);
  top: 50%;
  position: relative;
}