body {
    background: #fff5;
  }
  
  table {
    margin: 0 auto;
    border-collapse: collapse;
    background: black;
  }
  
  td {
    height: 80px;
    width: 80px;
    background-color: gray;
    font-size: 48px;
    text-align: center;
    cursor: pointer;
  }
  
  tr:nth-child(odd) td:nth-child(even),
  tr:nth-child(even) td:nth-child(odd) {
    background: white;
  }
  
  h1{
    display: flex;
    justify-content: center;
    align-items: center;
  }

  .alf {
    background-color: #fff; 
    font-size: 25px;
    margin: auto;
  }

  

  td:hover {
    background-color: yellow;
  }

  td:hover:after {
    opacity: 1;
    transition: all 0.1s ease 0.5s;
    visibility: visible;
    
  }

  td:after {
    content: attr(title);
    max-width: 200px;
    background-color: #000;
    color: #fff;
    position: absolute;
    text-align: center;
    padding:  0.25rem 0.5rem;
    border-radius: 0.25rem;
    font-style: normal;
    font-weight: 400;
    line-height: 1.5;
    z-index: 99999;
    visibility: hidden;
    font-size: 15px;
   }