.app {
  position: absolute;
  top: 0;
  left: 0;
  bottom: 0;
  right: 0;
  display: flex;
  justify-content: center;
  align-items: center;
  font-family: sans-serif;
  font-size: 1.5rem;
}

.app.dark {
  background-color: black;
  color: white;
}

button {
  background-color: transparent;
  color: inherit;
  padding: 3em;
  font-size: inherit;
  border-style: none;
  cursor: pointer;
}