body {
  background-color:#89c2d9;
  text-align:center;
  color:#3c6e71;
  }

a {
  text-decoration: none;
}

.project-container{
  margin:auto;
  padding-top:50px;
  width:80%;
}

.exercises-container {
  margin:auto;
  padding-top:50px;
  width:80%;
}

table { 
  margin:auto;
}
th {
  padding:10px 20px;
}
td {
  padding: 5px;
}
.topnav  {
  overflow: hidden;
  background-color: #215f88;
}

.topnav a  {
  float: left;
  color: #99acc2;
  text-align: center;
  padding: 14px 16px;
  text-decoration: none;
  font-weight:bold;
  font-size: 18px;
}

.topnav a:hover  {
  background-color: #99acc2;;
  color: #215f88;
}

#end a {
  font-size:15px;
  text-decoration: none;
}

.certificates {
  display:flex;
  flex-direction: column;
}

.certificates a {
  border: 3px solid rgba(71, 49, 42, 0.979);
  box-shadow: -3px 3px black;
  font-size: 1.3em;
  margin: 20px auto;
  width: 45%;
}