html {
  overflow: hidden;
  background-color: rgb(255,255,255);
  transition: 8s background-color;
}
body {
  overflow: hidden;
  background: linear-gradient(to right, rgb(0,0,0) 0%,rgba(192,192,192,0.75) 50%,rgb(0,0,0) 100%);
}
div.bande {
  position:absolute;
  width:250px;
  height:100%;
  left:calc(50% - 125px);
  top:0;
  background-color: rgba(255,255,255,0.85);
  box-shadow: 0 0 64px rgba(0,0,0,0.15);
  border:1px solid rgba(0,0,0,0.1);
  border-top:0;
  border-bottom:0;
}
div.bande div.logo {
  position:absolute;
  width:188px;
  height:250px;
  left:calc(50% - 94px);
  top:calc(55% - 125px);
  transition:1s;
  opacity:0;
}
div.bande div.active {
    top:calc(50% - 125px);
    opacity:1;
}