*{margin: 0 auto 0 auto; padding: 0;}

body { background: #000 url("imagenes/trama_comercial.jpg"); 
    color: white;
    width: auto; 
    height: auto;}

.cuerpo{max-width: 900px ; height: auto;}
 
header{background: #fff; width: 100%; height: 180px;}
header nav{width: 100%; height: 30px;}
header nav ul{ list-style-type: none;}
header nav ul li{display: inline; margin: 7px;}
header nav ul li a{text-decoration: none; color: #fff;}
header nav ul li a:hover{text-decoration:none; background-color: #d0d0d0; color: #fff;}

.menu { background: #B9BBBD; max-width: 900px; height: 20px; text-align: center; margin: 20px auto 10px auto; padding: 4px;
        font-family: arial; font-size: 14px;} 

.logo{margin: 10px 10px 10px 48px;}
.login{position: relative; float: right; margin: 10px 48px 10px 10px;}

aside{width: 100%; background: #fff; min-height: 210px;}
.article1 {position: relative; float: left; margin: 50px 50px 50px 100px; }
.article2 {position: relative; float: left; margin: 20px 8px 20px 26px; }
.article3 {position: relative; float: right; margin: 20px 48px 20px 18px;}

section{width: 100%; background: #fff; min-height: 300px; }
section article img {position: relative; float: right; margin: 30px 50px 30px 50px; }

.separador{clear: both; width: 100%;}

.legal { font-size: 10px; color: #9a9c9d; text-align: center; padding: 15px;}
footer {background: #fff; }