add icon to the post thumbnail

site.css

article{
    position:relative;
    &:after{
      content: "\f15c";
      font-family: FontAwesome;
      font-style: normal;
      font-weight: normal;
      text-decoration: inherit;
      /*--adjust as necessary--*/
      color: $brand-main-color;
      font-size: 2rem;
      position: absolute;
      top: 1.8rem;
      right: 2.2rem;
      z-index:2;
    }
    &:before{
      content: "";
      display:block;
      position: absolute;
      top: 1rem;
      right: 1rem;
      height:4rem;
      width:4rem;
      background: #FFFFFF;
      z-index:1;
      border-radius:50%;
      opacity: .8;
    }
  }
  article.format-video{
    position:relative;
    &:after{
      content: "\f04b";
    }
  }