Mi pagina se deforma al cerrar el navegador y se encima la informacion

[CMushroom]

mi pagina se ve prfecta y todo pero sorpresa no habia minimizado el navegador y o no , se hace pedazos (no literalmente jajaj) ayudenme porfas.

Código:

css

@charset "utf-8";

body, html { 
/*background-image:url(../imagenes/colorado%20gris.jpg);*/
	margin: 0px; 
}

.Cabecera{
	float:left; 
	width: 100%;
	height: 170px;
	background-image:url(../imagenes/background-fullsite-1.jpg);
}

.FormularioBuscador{
	float:left; 
	width: 20%;
	padding-top: 10px;
}

.BannerCabecera{
	float: left; 
	width: 60%;
}

.FormularioLogeo{
	float:right; 
	width: 20%;
	padding-top: 10px;
}

.BarraLateralIzquierda{
	float:left; 
	width: 20%;
	margin: 10px 0px 10px 0px; 
}

.ContenedorPrincipal{
	float:left; 
	width: 60%;
}

.Articulo{
	float:left; 
	padding: 30px 30px 10px 10px;
	text-align:justify;
}

.Comentarios{
	padding: 40px 40px 10px 10px;
	word-break: break-all;
}

.BarraLateralDerecha{
	float:right; 
	width: 20%;
}

.Chat{
	float:left; 
    margin: 0% 5% 0% 5%;
	font-size:12px;
}

.MensajesChat{
	text-decoration:none;
	font-size:8px;
}

.ResultadoBusquedas{
	padding: 40px 40px 10px 10px;
	padding-bottom: 10px;
	text-align:justify;
	font-size: 16px;
}

.ResultadoRecomensaciones{
	margin: 10px 10px 10px 10px;
	padding-bottom: 10px;
	text-align:justify;
	font-size: 13px;
}
.Footer{
	width: 100%;
	height: 170px;
}

img.shadow {
	background: url(shadow-1000×1000.gif) no-repeat right bottom;
	padding: 0px 10px 0px 10px;
}

a{text-decoration:none;}

a:link {
	font-family: Arial;
	text-decoration:none; color: #09F;
} /* Link no visitado*/

a:visited {
	text-decoration:none; color:#03C
} /*Link visitado*/

a:active {
	text-decoration:none; color:#936; background:#EEEEEE
} /*Link activo*/

a:hover {	
	text-decoration:none; color:#FFF; background: #09C
} /*Mause sobre el link*/

.fecha {
	font-family: Arial, Helvetica, sans-serif;
	font-size: 10px;
	color: #FF0000;
}
.mensaje {
	font-family: "Lucida Sans Unicode", "Lucida Grande", sans-serif, sans-serif;
	font-size: 10px ;
	color: #333399;
	font-weight: bold;
}

.usuario {
	font-family: Arial, Helvetica, sans-serif;
	font-size: 11px;
	color: #000000;
	font-weight: bold;
}

.button 
{
	border: 1px solid #DDD;
	border-radius: 3px;
	text-shadow: 0 1px 1px white;
	-webkit-box-shadow: 0 1px 1px #fff;
	-moz-box-shadow:    0 1px 1px #fff;
	box-shadow:         0 1px 1px #fff;
	font: bold 11px Sans-Serif;
	padding: 6px 10px;
	white-space: nowrap;
	vertical-align: middle;
	color: #666;
	background: transparent;
	cursor: pointer;
}
.button:hover, .button:focus 
{
	border-color: #999;
	background: -webkit-linear-gradient(top, white, #E0E0E0);
	background:    -moz-linear-gradient(top, white, #E0E0E0);
	background:     -ms-linear-gradient(top, white, #E0E0E0);
	background:      -o-linear-gradient(top, white, #E0E0E0);
	-webkit-box-shadow: 0 1px 2px rgba(0,0,0,0.25), inset 0 0 3px #fff;
	-moz-box-shadow:    0 1px 2px rgba(0,0,0,0.25), inset 0 0 3px #fff;
	box-shadow:         0 1px 2px rgba(0,0,0,0.25), inset 0 0 3px #fff;
}

.button:active 
{
	border: 1px solid #AAA;
	border-bottom-color: #CCC;
	border-top-color: #999;
	-webkit-box-shadow: inset 0 1px 2px #aaa;
	-moz-box-shadow:    inset 0 1px 2px #aaa;
	box-shadow:         inset 0 1px 2px #aaa;
	background: -webkit-linear-gradient(top, #E6E6E6, gainsboro);
	background:    -moz-linear-gradient(top, #E6E6E6, gainsboro);
	background:     -ms-linear-gradient(top, #E6E6E6, gainsboro);
	background:      -o-linear-gradient(top, #E6E6E6, gainsboro);
}
		
.button:after
{
	content: "";
	display: inline-block;
	width: 0;
	height: 0;
	border-top: 4px solid #999;
	border-left: 4px solid transparent;
	border-right: 4px solid transparent;
	margin: 0 0 0 4px;
	position: relative;
	top: -1px;
}
	
.button:hover:after 
{
	border-top-color: black;
}


UL LI {
   list-style-image: url(../imagenes/estrella.png);
}


.Formulario {
    font-family: 'Raleway', 'Lato', Arial, sans-serif;
}

.Formulario h1 {
    font-size: 12px;
    padding-bottom: 5px;
}

.Formulario input[type=text],
.Formulario input[type=password] {
    border: 1px solid #4e3043;
    border: 1px solid rgba(78,48,67, 0.8);
    background: #666;
    border-radius: 2px;
    box-shadow: 
        0 1px 0 rgba(255,255,255,0.2), 
        inset 0 1px 1px rgba(0,0,0,0.1);
    -webkit-transition: all 0.3s ease-out;
    -moz-transition: all 0.3s ease-out;
    -ms-transition: all 0.3s ease-out;
    -o-transition: all 0.3s ease-out;
    transition: all 0.3s ease-out;

    font-family: 'Raleway', 'Lato', Arial, sans-serif;
    color: #FFF;
    font-size: 14px;
}

.Formulario input[type=text]:hover,
.Formulario input[type=password]:hover {
    border-color: #0CF;
	background: #CCC;
	color:#000;
}

.Formulario label {
    display: none;
    padding: 0 0 5px 2px;
    cursor: pointer;
}

.Formulario label:hover ~ input {
    border-color: #333;
}

.no-placeholder .Formulario label {
    display: block;
}

.Footer{     
	float: left;
	width: 100%;
	height: 100%;
	background-image:url(../imagenes/background-fullsite-1.jpg);
}

.Footer .text{
	width: 16%;
	margin: 5px 2% 10px 2%;
	float: left;
	color: #000;
	font-size: 16px;
	text-align: justify;
	letter-spacing: 0px;
}

.Footer .text h1{
	border-bottom: 1px dashed #ccc;
	color:#09F
}

aca el index

Código PHP:

 <!DOCTYPE html>
<html lang = "es">
    <head>
        <meta charset="UTF-8" />
        <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1"> 
        <meta name = "description" content = "revista web con los mejores articulos"/>
        <meta name = "keywords" content = "articulos,ciencia,arte,cultura,tecnologia,eventos,morelos,cuernavaca,uaem"/>
        <meta name = "author" content = "C-Mushroom" />
        <meta name = "viewport" content = "width=device-width, initial-scale=1.0"> 
        <title>Base WebMagazine</title>
        <link rel = "shortcut icon" href="imagenes/c-mushroom.ico" type = "image/x-icon"/>
        <link rel = "stylesheet" type = "text/css" href = "css/estilo.css"/>
       </head>

    <body>
        <div class = "Cabecera">
            <?php include('Header.php');?>
        </div>
        
           <div class = "BarraLateralIzquierda">
            <?php include('ListaCategoria.php');?>
            <?php include('Administrador.php');?>        
         </div>
            
        <div class = "ContenedorPrincipal">
               <?php include('Buscador.php');?>  
            <?php include('ListaNoticia.php');?>
        </div>
            
        <div class = "BarraLateralDerecha">
            <?php include('Chat.php');?>
            <?php include('Recomendaciones.php');?>
        </div>
        
        <div class = "Footer">
            <?php include('Footer.php');?> 
        </div>
    </body>
</html>  

y aqui la foto normal del index



y aca deformada