WordPress: Using featured images (thumbnails) as hero backgrounds (2 of 2).

style.scss

.hero-background-image[style] {
  height: 340px !important;
  background-color: #888 !important;
  background-size: auto 340px !important;
  @media (min-width: 768px) {
    height: 440px !important;
    background-size: auto 440px !important;
  }
  @media (min-width: 1024px) {
    height: 500px !important;
    background-size: auto 500px !important;
  }
  @media (min-width: 1200px) {
    height: 600px !important;
    background-size: auto 600px !important;
  }
}