#robot { width: 300px; transition: all 1.4s cubic-bezier(0.075, 0.82, 0.165, 1) ; } 
.move-right { transform: translatex(300px); }

#battery {
  position: absolute;
  width: 80px;
  top: 200px;
  left: 200px;
  transition: none;
  cursor: pointer;
}

 #start, #overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(202, 52, 52, 1);
    color: white;
    font-size: 48px;
    display: flex;
    justify-content: center;
    align-items: center;
    visibility: hidden;
    z-index: 100;
  }

  #start {
    visibility: visible;
    background: rgb(red, green, blue);
  }