body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  margin: 0;
  padding: 0;
  background-color: #f4f4f4;
  color: #333;
}

header {
  background-color: #fff;
  padding: 20px;
  text-align: center;
  border-bottom: 1px solid #ddd;
}

nav ul {
  list-style-type: none;
  margin: 20px 0 0;
  padding: 0;
}

nav ul li {
  display: inline-block;
  margin: 0 15px;
}

nav ul li a {
  text-decoration: none;
  color: #007bff;
  font-weight: bold;
}

nav ul li a:hover {
  text-decoration: underline;
}

main {
  padding: 20px;
  min-height: calc(100vh - 220px);
}

footer {
  background-color: #333;
  color: #fff;
  text-align: center;
  padding: 20px;
  position: relative;
  bottom: 0;
  width: 100%;
}

IMG.centered {
	display: block;
    margin-left: auto;
    margin-right: auto;

}