body, html {
    height: 100%;
  }

.bg {
    /* The image used */
    background-image:url("../images/clocks.jpg");
  
    /* Full height */
    height: 100%;
  
    /* Center and scale the image nicely */
    background-position: center;
    background-repeat: no-repeat;
    background-size: cover;
  }

  .vertical-center {
    margin: 0;
    position: relative;
    top: 50%;
    -ms-transform: translateY(-50%);
    transform: translateY(-50%);
    text-align: center;
  }

  .sound_container {
    position: relative;
  }