html,
body {
  margin: 0;
  padding: 0;
  width: 100%;
  height: 100%;
}

.app-root {
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  background: lightgray;
}

.content {
  max-width: 100%;
  max-height: 100%;
}