body
{
  text-align:  center;
  background-image: linear-gradient( rgba(0, 0, 0, 0.5), rgba(0, 0, 0, 0.5) ), url('background.jpg');
  background-repeat: no-repeat;
  background-size: cover;
}

a
{
  text-decoration: none;
  color: white;
  padding: 20px;
}

a:hover
{
  color: grey;
}