.content {
    display: flex;
    justify-content: space-between;
    flex-direction: column;
    height: 620px;
  }

  .content .upper {
    justify-content: normal;
  }

  /* Just to show container boundaries */
  .content .upper, .content .bottom, .content .upper > * {
    /*border: 1px solid #ccc;*/
  }

  #prevBtn, #nextBtn, #btnNext1, #btnNext2, #btnBack2, #btnNext3, #btnBack3, #btnNext4 {
    width: 8rem;
  }