body {
    font-family: Arial, sans-serif;
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
  }
  
  .materia {
    border: 1px solid #000;
    padding: 20px;
    margin: 10px;
    width: fit-content;
  }
  
  button {
    margin-top: 20px;
    clear: both;
  }