styles.css

.navigation
{
    border: 1px solid black;
    border-collapse: collapse;
}
.navigation_cell
{
    text-align: center;
    color: blue;
    border: 1px solid black;
    padding-left: 30px;
    padding-right: 30px;
}
h1
{
    text-align: center;
    font-family: sans-serif;
}
h3
{
    text-align: center;
    font-family: sans-serif;
    font-size: 18px;
    font-style: italic;
    color: #555588;
}
.button {
  background-color: #4CAF50; /* Green */
  border: none;
  color: white;
  padding: 15px 303px;
  text-align: center;
  text-decoration: none;
  display: inline-block;
  font-size: 16px;
}

.button:visited {
  color: white;
}