a:link, a:visited {
  background-color: blue;
  color: white;
  border: 2px solid blue;
  padding: 10px 20px;
  text-align: center;
  text-decoration: none;
  display: inline-block;
}

a:hover, a:active {
background-color: white;
  color: black;

}
ul {
  list-style-type: none;
  margin: 0;
  padding: 0;
}
li {
  display: inline;
}