body {
  font-family: sans-serif;
  padding: 20px;

  display: flex;
  flex-direction: column;
  align-items: center; /* centers horizontally */
}

#grid-container {
  display: grid;
  gap: 15px;
  margin: 20px 0;
  justify-content: center; 
}

button.grid-btn {
  width: 80px;
  height: 40px;
}