body{
  background-color: Black;
  color: white;
  text-align: center;
  margin: 0px;
  font-family: Helvetica;
}
a{
  text-decoration: none;
  color: DodgerBlue;
}
h1{
  font-size: 38px;
}
h2{
  font-size: large;
  font-weight: bold;
  text-align: left !important;
  margin-left: 10%;
  margin-top: 5%;
}
pre {
  text-align: left !important;
  white-space: pre-wrap;
  margin-left: 5%;
  margin-top: 1%;
  font-family: Helvetica;
}
.buttons{
  margin-top:10%;
}
ul{
  margin-top:75px;
  list-style:none;
  padding-left:0px;
  padding-top:10px;
  font-size: 24px;
}
/* Add a black background color to the top navigation */
.topnav {
  floet: center;
  background-color: black;
  overflow: hidden;
  text-align: center;
}
/* Style the links inside the navigation bar */
.topnav a {
  color: #f2f2f2;
  text-align: center;
  padding: 14px 16px; 
  text-decoration: none;
  font-size: 17px;
  display:inline-block;
}

/* Change the color of links on hover */
.topnav a:hover {
  background-color: #ddd;
  color: black;
}
.topnav li{
  display:inline;
}
/* Add a color to the active/current link */
.topnav a.active {
  background-color: #0000FF;
  color: white;
}

/* Ad for w3I */
#nice {
  animation: color-change 4s infinite;
}
@keyframes color-change {
  0% { color: green; }
  20% { color: blue; }
  40% { color: red; }
  60% { color: green; }
  80% { color: blue; }
  100% { color: red; }
}
div.ad{
  position:absolute;
  bottom: 5%;
  white-space: pre;	
  left:50%;
  margin-left:-100px;
}