body {
  background-color:#4c566a;
  color:#eceff4;
  background-image:url('back.jpg');
  background-repeat:no-repeat;
  background-attachment:fixed;
  background-position:center center;
}
@media (prefers-color-scheme: light) {
  body {
    background-color:#d8dee9;
    color:#2e3440;
  }
}
.container {
    position: absolute;
    top: 50%;
    left: 50%;
    -moz-transform: translateX(-50%) translateY(-50%);
    -webkit-transform: translateX(-50%) translateY(-50%);
    transform: translateX(-50%) translateY(-50%);
    background-color: rgba(76, 86, 106,0.8);
    width: 75%;
    border: 6px solid #2e3440;
    padding: 10px;
    margin: 10px;
}