Re,
Regarde :
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="fr" lang="fr">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>TEST</title>
<style>
body{
background-color: #cbe9d8;
margin: auto;
font-family: "Times New Roman", Times, serif;
margin-top: 10px;
margin-bottom: 10px;
width: 800px;
}
#logo{
witdh: 800px;
height: 120px;
background-repeat: no-repeat;
border: 2px double black;
}
#menu{
width: 600px;
margin: auto;
border: 1px solid #968d00;
overflow: hidden;
}
a{
text-decoration: none;
}
ul {
list-style-type: none;
}
.menuhaut li {
float: left;
}
.menuhaut a {
margin: 0 3px;
width: 120px;
height: 17px;
display: block;
text-align: center;
border: 1px solid black;
text-decoration: none;
color: #000000;
background: #fff;
}
.menuhaut a:hover {
background: #c6dcc7;
border: 1px solid black;
}
#contenu{
float: center;
margin-top: 50px;
border: 2px black solid;
padding: 10px;
}
.bas{
margin-top: 7px;
border: 2px black solid;
padding: 5px;
font-size: 15px;
text-align: right;
font-style: italic;
}
h1, h2{
color: #2c5ba1;
text-align: center;
}
</style>
</head>
<body>
<div id="logo">
<!-- Logo -->
</div>
<div id="menu">
<ul class="menuhaut">
<!-- Menu du haut -->
<li><a href="">Nos projets</a></li>
<li><a href="">Nos articles</a></li>
<li><a href="">A propos</a></li>
<li><a href="">Sites/blogs</a></li>
</ul>
</div>
<div id="contenu">
<!-- Contenu -->
<h1>Page d'accueil.</h1>
<h2>Test h2</h2>
Test plop plop<br />
</div>
<div class="bas">
<a href="">Nos projets </a> --
<a href="">A propos</a> --
Developpe par *********
</div>
</body>
</html>
Vérifie ton css, il y a quelques boulettes ...
float : center ???
witdh: 800px; ???