#main{
    padding: 20px;
  font-family: sans-serif;
  background: #f2f2f2;
}
  img:not(label img) {
    width: 100%; /* need to overwrite inline dimensions */
    height: auto;
  }
  h2 {
    margin-bottom: .5em;
  }
  .grid-container {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    grid-gap: 1em;
  }
  a{
    text-decoration: none;
    color:black;
  }
  #visor{
    display:block;
    margin:0 auto;
    width:300px;
  }

  #adelante, #atras{
    background-color:#DC3545;
    color: white;
    border: 0px;
    font-size: 15px;
    padding: 14px 30px;
    border-radius: 8px;
    margin-top: 20px;
  }
  
  #adelante:hover, #atras:hover{
    background-color: #C82333;
    cursor:pointer;
  }

  #adelante{
    float:right;
  }
  
  @media (max-width : 900px){
    #visor{
      display:none;
    }
  }