Code for the header

_block-header.scss

.block-header {
  margin-top: 0;
  position: relative;

  h1 { 
    position: absolute;
    width: 100%;
    left: 6vw;
    top: 14vw;
    font-weight: 600;
    font-size: calc(100vw / 12);
    line-height: 1;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.5);
  }
  .pre-title {
    color: lighten($dark-blue, 50%);
    display: block;
    font-size: calc(100vw / 24);
    font-weight: 600;
    margin: 0;
    text-transform: uppercase;
    @include media($tablet) {
      font-size: calc(100vw / 48);
    }
  }

  video {
    width:100%;
    height: auto;
    background-image: url(https://s3.amazonaws.com/cdn.news.ucsc.edu/poster-frame.jpg);
    -webkit-background-size:cover; 
    -moz-background-size:cover; 
    -o-background-size:cover; 
    background-size:cover; 
  }
}