body,html{
height:100%;
width:100%;
background-color:brown;
padding:0px;
margin:0px;
}

#bloc1_de_body{
height:20px;
width:100px;
background-color: red;
margin-left:20px;
margin-bottom:20px;
}
#bloc2_de_body{
height:40px;
width:200px;
background-color: yellow;
margin-top:8px;
margin-bottom:8px;
}
#bloc3_de_body{
width:600px;
background-color: blue;
margin-top:20px;
}
#bloc_a_de_bloc3{
height:30px;
background-color:gray;
margin-left:30px;
}

#bloc_b_de_bloc3{
background-color:green;
width:350px;
margin:8px;
}

#bloc4_de_body{
height:50px;
width:150px;
background-color: red;
margin:25px 0px 10px 60px;
}
