body{
  background-color:lightgray;
  font-family:Arial,Helvetica,sans-serif;
}

#container { 
  width:1100px;
  margin:0px auto;
  border:4px solid gray;
}

header {
  background-color:red;
  height:100px;
  width:100%;
  margin:0px;
  text-align:center;
  line-height: 100px;
  color: antiquewhite;
  border-bottom: 2px solid black
}

nav ul li {
  float: left;
  list-style: none;
  margin: 20px;
  line-height:10px;
}