html {
  font-family: sans-serif;
}

body {
	max-width: 800px;
	margin-left:auto;
	margin-right:auto;
  margin-top: 50px;
  margin-bottom: 50px;
  background-color: #aaa;

}

th, td {
	padding: 5px;
	text-align:center;
}

table, th, td {
    border: 1px solid black;
}

p{
  text-align: justify;
}

#main{
  padding-left: 20px;
  padding-right: 20px;
  padding-top: 20px;
  padding-bottom: 20px;
  background-color: #fff;
  border: 1px solid black;
  border-style: solid;
}

#header{
  text-align: center;
}

ul#menu {
  list-style-type: none;
  margin: 0;
  padding: 0;
  overflow: hidden;
  border: 1px solid #ddd;
  background-color: #eee;
  display: flex;
  justify-content: space-between;
}
li#menu {
  float: left;
}
li#menu a#menu {
  display: block;
  color: #333;
  text-align: center;
  padding: 12px 25px;
  text-decoration: none;
}
li#menu a#menu:hover {
  background-color: #ddd;
}