body {
  font-family: Arial, sans-serif;
  margin: 0;
  padding: 0;
  background: #f2f2f2;
}
header {
  background: #444;
  color: #fff;
  padding: 1em;
  text-align: center;
}
nav ul {
  list-style: none;
  background: #333;
  margin: 0;
  padding: 0;
  display: flex;
  justify-content: center;
}
nav ul li {
  margin: 0;
}
nav ul li a {
  color: white;
  padding: 1em;
  display: block;
  text-decoration: none;
}
nav ul li a:hover {
  background: #555;
}
main {
  padding: 2em;
}
table {
  width: 100%;
  border-collapse: collapse;
}
th, td {
  padding: 0.75em;
  border: 1px solid #ccc;
}
footer {
  background: #444;
  color: white;
  text-align: center;
  padding: 1em;
  position: fixed;
  bottom: 0;
  width: 100%;
}