html,
body,
.App,
#root {
  padding: 0;
  margin: 0;
  position: relative;
  height: 100%;
}
.guides.horizontal {
  position: absolute;
  height: 30px;
  left: 30px;
  width: calc(100% - 30px);
}
.guides.vertical {
  position: absolute;
  width: 30px;
  top: 30px;
  height: calc(100% - 30px);
}
.viewer {
  position: absolute;
  top: 30px;
  left: 30px;
  width: calc(100% - 30px);
  height: calc(100% - 30px);
}

.viewport {
  position: relative;
  border: 2px solid #ccc;
  width: 400px;
  height: 600px;
}