img {
    display: block;
    margin-left: auto;
    margin-right: auto;
    padding-top: 20px;
    width: 600px;
  }
  div.b {
    text-align: center;
  }
  div.a {
    text-align: center;
    padding-top: 30px;
  }
  footer {
    background-color: rgb(0, 0, 0);
    clear: both;
    position: relative;
    bottom: 0;
    width: 100%;
    height: 7vh;
    display: table;
    text-align: center;
    margin-left: auto;
    margin-right: auto;
    padding-top: 1em;
  }
  
  footer nav a {
    color: rgb(103, 191, 254);
    text-decoration: none;
    font-size: 1em;
    margin: 0.77em;
    text-align: left;
    border-radius: 12px;
    padding: 0.28em 0.18em 0.13em;
  }
  
  footer nav a:hover {
    color: rgb(25, 88, 33);
    transition: 0.35s;
  }