td {
  text-align: center;
}
body {
  background-color:grey;
}
nav {
background-color:orange;
padding:7px;
}
table, th, td {
  border: 1px solid black;
  border-collapse: collapse;
}
h3 {
  margin: left;
  width: 50%;
  border: 3px solid black;
  padding: 10px;
}