body {
  background-color: #000000;
  color: white;
  font-family: Verdana;
  text-align: center;
}
center {
  background-color: #000000;
  text-align: center;
  border: 3px solid black;
}
img {
  display: block;
  margin-left: auto;
  margin-right: auto;
  border: 3px solid black
}
a:link {
  color: red;
}

/* visited link */
a:visited {
  color: yellow;
}

/* mouse over link */
a:hover {
  color: green;
}

/* selected link */
a:active {
  color: blue;
}