*{margin: 0; padding: 0}
body{background: #fd8b29}
.contenedor {width: 960px; margin: 0 auto 0 auto; }



header {background: #4add37; height: 130px;}
nav {background:#ff67e2; height: 50px;} 
main {background: #6339c3; height: 500px;}
section {background: #009dff; height: 500px; width: 70%; position: relative; float: left}
aside {background: #7c7b77; height: 500px; width: 30%; position: relative; float: left}
footer {background: #d0deb5; height: 70px;} 
section article {background: #ffe200; height: 200px; width:30% ; position: relative; float: left; box-sizing: border-box; margin: 1.5%;padding: 2%}

.articulito {background: #ffe200; height: 250px; width:27% ; position: relative; float: left; box-sizing: border-box; margin: 2%;}