.nav 
{
  background-color: red; 
  list-style-type: none;
  color: pink;
  text-align: center;
  margin: 0;
  padding: 0;
}

.nav li 
{
  display: inline-block;
  font-size: 20px;
  padding: 20px;
  color: yellow;
  text-align: center;
}

.backGround 
{
  height: 100vh;
  background-image: linear-gradient(lightBlue, red);
  background-repeat: no-repeat;
}

.center 
{
  margin: auto;
  width: 100vh;
  border: 3px solid #73AD21;
  padding: 10px;
}