header{
    background-color: gainsboro;
    color:black;
    padding:5px;
    width:420px;
    height: 500px;
    position:fixed;
    margin-left: 840px;
    font-family: "Arial";
    font-size: 13px;
    text-align: justify;
}

body{
    width:1200px;

}

h1{
    font-family:"Arial";
    padding:10px;
    font-style: normal;
    border-bottom: solid;
    text-align: justify;
    text-align: center; 
}

h2{
    margin-left:15px;
    margin-bottom: 8px;
    margin-top: 20px;
    font-family: "Arial";
}

h3{
    margin-left:15px;
    margin-bottom: 8px;
    margin-top: 20px;
    font-family: "Arial";
}
.ressources{
    margin-left:30px;
    margin-bottom: 10px;
    padding:5px;
    background-color: gainsboro;
    color :black;
    font-family: "Arial";
}

a{
    margin-left:20px;
    background-color: gainsboro;
    padding: 5px;
    font-family:"Arial";
    border-radius: 5px;
    text-decoration: none;
    margin-top:100px;
}

a:hover{
    background-color: white;
    color:black;
    border-color:black;
    font-style: bold;
}

.texte1{
    width:480px;
    ont-style: italic;
    font-size: 17px;
    font-family:"avenir";
    padding:10px;
    float:right;
    margin-right:430px;
    text-align: justify;
}

.presentation{
    font-size: 18px;
    font-family:"Arial";
    padding:10px;
    float:left;
    margin-left:5px;
    margin-right: 450px;
    text-align: justify;
}




p{
    font-style: italic;
    font-size: 17px;
    font-family:"avenir";
    margin-left:15px;
    margin-right: 450px;
    text-align: justify;
}




.liens{
    padding:10px;
    font-family: "Arial";
    font-size: 16px;
    margin-left:20px;
    margin-top:8px;
    margin-bottom:20px;
}

img {
  vertical-align:middle;
}  


.image{
    width:420px;
    height: 255px;
    float : right;
}

.aperçu{
    width:790px;
    height: 40px;
    float:left;
    margin-left: 5px;
    margin-right: 450px;
    margin-top: auto;
    padding:10px;
    border-style: solid;
    font-family: "Arial";
    text-align: center;
}