body {
 background-image:url(http://www.wallsave.com/wallpapers/1366x768/paysage-montagne/344996/paysage-montagne-nordique-belle-image-de-fond-d-344996.jpg);
 background-repeat: no-repeat ; 
 background-attachment: fixed ;
}
h3 {
  margin-left: auto;
  margin-right: auto;
  width: 200;
}

table{
margin-left:auto;
margin-right:auto;
}
td,th{ 
border:thin solid black;
font-family: "Trebuchet MS"
text-align:center; 
padding:5px; 
}
h1 {
 font-size: 200%; 
 color: navy; 
 text-align: center;
 }
 h2 {
 font-size: 100%; 
 color: black; 
 text-align: center;
 }
 h6 {
 font-size: 100%; 
 color: Navy; 
 text-align: center;
 }
img {
width:400px;
height:400px;
display: block;
margin-left: auto;
margin-right: auto;
}
li{
margin-top : 10px; 
margin-bottom : 10px; 
font-size:25px
]}