style.css

.header {
  padding: 60px;
  text-align: center;
  background: #1abc9c;
  color: white;
  font-size: 30px;
  font-family: 'Gill Sans', 'Gill Sans MT', Calibri, 'Trebuchet MS', sans-serif;
}

body { 
  margin: 0;   /* Remove body margins */
  background: #227a6f;
}

.topnav {
  overflow: hidden;
  background-color: #000;
  color: #f2f2f2;
}

.topnav a {
  float: left;
  color: #f2f2f2;
  text-align: center;
  padding: 14px 16px;
  text-decoration: none;
  font-size: 17px;
  font-family: 'Gill Sans', 'Gill Sans MT', Calibri, 'Trebuchet MS', sans-serif;
}

a:visited {
  color: inherit;
  text-decoration: none;
 }

.topnav a:hover {
  background-color: #ddd;
  color: black;
}

.active {
  background-color: #4caf50;
  color: white;
}

.content {
  padding: 60px;
  text-align: center;
  background: #4caf50;
  color: white;
  font-size: 30px;
  font-family: 'Gill Sans', 'Gill Sans MT', Calibri, 'Trebuchet MS', sans-serif;
}

.content paragraph {
  color: white;
  font-family: 'Gill Sans', 'Gill Sans MT', Calibri, 'Trebuchet MS', sans-serif;
  font-size: 18px;
}