body{width:800px;
     margin:auto;
	 background-color:yellow;
	 font-family:Arial}
h1{text-align: center;
   color: blue;
   font-size: 40px;}
h2{color: white;
   background-color: black;}
h3{	color:white;
	background-color:green}
p{font-family: Verdana;
	margin-left: 20px;
	margin-right: 100px;}
li{	margin-left:50px}

iframe{display:block;
	margin-left:auto}
.bouton{float:right ;
		background-color:orange;
		font-size:30px;}
h2:hover {color: blue;
	background-color: pink;}