h1 {color:blue; background-color:yellow; text-align:center;1border:3px; margin:2px; padding:2px;}
.disease{color:red; font-size:30; width:25%; margin:2em; text-align:center; border: 2px blue solid; padding:5px; text-align:center;}
.bgcolor{background-color: pink;}
.images{margin-left:2em;}
.nav{border: 3px blue solid;
  background-color:cyan;
  padding: 14px 28px;
  font-size: 16px;
  cursor: pointer;
  display: inline-block;}