body {
  max-width: 30em;
  margin: 2em auto;
  text-align: center;
}

#grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0.5em;
  margin: 1em 0;
}

.tile.selected {
  outline: 3px solid;
  font-weight: bold;
}

.tile.solved-row {
  grid-column: 1 / -1;
  white-space: pre-line;
}

.controls {
  margin: 1em 0;
}