/* Set a background image by replacing the URL below */
body {
/*    background: url('https://source.unsplash.com/twukN12EN7c/1920x1080') no-repeat center center fixed; */
    background: url('../imgs/gray.jpg') no-repeat center center fixed;
    -webkit-background-size: cover;
    -moz-background-size: cover;
    background-size: cover;
    -o-background-size: cover;
  }