html {
  height: 100%;
  width: 100%;
  background-color: red;
}
/* p {
  color:yellow;
  font-size:20px;
  font-family:'comic sans ms'; */
}
h1 {
  color: yellowgreen;
  font-size: 40px;
  font-family: 'times new roman';
  text-align: center;
}
nav {
  color:red;
}
 nav ul{
   color:blue;
   text-align: center;
 }
   nav ul li {
     color:yellow;
     text-align:center;
     list-style-type: none;
   }
nav ul li a {
  color:indigo;
}
 
figcaption {
  text-align: center;
  font-family: 'comic sans roman';
  font-family: 20px
}

footer{
   background-color:blue;
  padding:10px;
  text-align: center;
}
li a:hover {
background-color: yellow;
}
.introduction  {
  color:yellow;
}
.main-page {
  color:green;
}
 ul {
   list-style-type: none;
   margin: o;
   padding: o;
   background-color:grey;
 }
 li {
   display:inline;
 }
 li a {
   display:block;
   color: green;
   text-align:center;
   padding:12px 16px;
   text decoration:none;
 }