#bitumen60-70 {
  font-family: Arial, sans-serif;
  border-collapse: collapse;
  width: 100%;
  text-align: center;
}

#bitumen60-70 td, #bitumen60-70 th {
  border: 1px solid #ddd;
  padding: 8px;
  text-align: center;
}

#bitumen60-70 tr:nth-child(even) {
  background-color: #f2f2f2;
}

#bitumen60-70 tr:hover {
  background-color: #ddd;
}

#bitumen60-70 th {
  padding-top: 12px;
  padding-bottom: 12px;
  text-align: left;
  background-color: #B4CBF0;
  color: dimgray;
  text-align: center;
}

.btn{

  position: relative;
  margin-top: 50px;
  left: 45%;

}