Some pbs whith my page

First you will have to go through your css file/s and delete all the 'margin-right: 300px;' declarations from the below css selectors, as marked in red below:

.affichage {

    font-size: 20px;

    color: #FFFFFF;

    background-color: #9F9F9F;

    margin-top: 20px;

    /*margin-right: 300px;*/

    padding-left: 0px;

    margin-bottom: 10px; /*degage de 10px l'image et le texte sous la banniere*/

    text-align: left;

}

.affichage2 {

    font-size: 16px;

    color: #4C4C4C;

    background-color: #DBDBDB;

    border: 2px #7A2870 solid; /* bordure du bloque texte couleur bordeaux taille 2 px solide*/

    margin-top: 40px;

    /*margin-right: 300px;*/

    padding-left: 0px;

    margin-bottom: 30px; /*degage de 10px l'image et le texte sous la banniere*/

    text-align: left;

}

.texte-illustration p {

    color: #2C2C2C;

    margin-top: 0px;

    /* margin-right: 300px;*/

    overflow: hidden; /* Contexte de formatage. Force le paragraphe à adapter sa largeur aux flottants adjacents. */

}

.texte-illustration p a {

    text-decoration: none;

    color: #7A2870;

    margin-top: 0px;

    /* margin-right: 300px;*/

    overflow: hidden; /* Contexte de formatage. Force le paragraphe à adapter sa largeur aux flottants adjacents. */

}

Once you have done that then add a <main> tag with the class name of 'main-content' right above your first opening 'header' <div> tag as below:

<main class="main-content">

<div class="header">

Then close the 'main' tag directly after your 'photo-logo' closing </div> tag and add an <aside> tag with the class name of 'sidebar' after the closing </main> tag, as below:

<p>Lorem ipsum dolor sit amet, consectetur</p>

<p>Lorem ipsum dolor sit amet, consectetur</p>

<p>Lorem ipsum dolor sit amet, consectetur</p>

</div>

</main>

<!-- end main-content -->

<aside class="sidebar">

Sidebar content goes here.

</aside>

<!-- end sidebar -->

Then add the below css selectors to your css stylesheet to position the 2 containers side-by-side and to push the 'footer' below them.

.main-content {

float: left;

width: 800px;

}

.sidebar {

float: left;

width: 400px;

background-color: yellow;

}

.footer {

clear: both;

}