#nt_spinner {
  height: 100%;
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  margin: 0 auto;
  background-color: #f4f4f4;
}

.spinner-border {
    display: inline-block;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    margin: auto;
    width: 3.5rem !important;
    height: 3.5rem !important;
    vertical-align: -0.125em;
    border: 2px solid #909090;
    border-left-color: transparent;
    border-radius: 50%;
    -webkit-animation: .75s linear infinite spinner-border;
    animation: .75s linear infinite spinner-border;
}

#nt_block_spinner {
  width: 10rem !important;
  height: 10rem !important;
}