body {
  text-align: center;
  font-family: sans-serif;
  background-color: #f8f8f8;
}

h1 {
  margin-top: 20px;
}

.info {
  margin: 10px;
  font-size: 18px;
  font-weight: bold;
  color: #333;
}

#puzzle {
  display: grid;
  grid-template-columns: repeat(4, 80px);
  grid-template-rows: repeat(4, 80px);
  gap: 5px;
  margin: 20px auto;
  width: max-content;
}

.tile {
  display: flex;
  justify-content: center;
  align-items: center;
  background-color: #3498db;
  color: white;
  font-size: 24px;
  font-weight: bold;
  cursor: pointer;
  border-radius: 8px;
  transition: 0.2s;
}

.blank {
  background-color: #ccc;
  cursor: default;
}