body{
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  margin: 0;
  height: 100vh;
}

#sheet {
  pointer-events: none;
  position: relative;
  width: 100%;
  height: 100%;
}

.hidden {
  display: none;
}

#start_pin {
  position: absolute;
  transform: translate(-50%,-100%);
}

.block {
  position: absolute;
  background: #ff000080;
  width: 80px;
  height: 80px;
  transform: translate(-50%,-50%);
}

.border {
 border: 5px solid black;
}

.window {
  overflow: hidden;
  height: 80vh;
  width: 80vw;
}

.dotted-grid {
  background-image: radial-gradient(circle, lightgrey 1px, rgba(0, 0, 0, 0) 1px);
}

.grid {
  background-image:
    linear-gradient(to right, lightgrey  1px, transparent 1px),
    linear-gradient(to bottom, lightgrey  1px, transparent 1px);
}