RESPONSIVE.CSS

body {

background:#FFFFFF;

font-family:Arial;

}

 

.contenedor {   /*contenedor es cualquier nombre*/

width:80%;

max-width:1000px; 

margin:0 auto;

overflow:hidden; 

}

 

header {

background:#EB4A33;

margin:20px 0; 

} 

 

main {

width:70%;

padding:20px;

background:#F9F713;

float:left;

box-sizing:border-box;

}

 

aside {

width:30%;

padding:20px;

background:#278ACF;

float:left;

box-sizing:border-box;

}

 

@media screen and (max-width: 800px){

body {

background:#AF5424; 

}

 

main {

width:100%;

    }

 

    aside {

width:100%;

    } 

}

 

@media screen and (max-width:400px){

.contenedor { 

width:100%;

    } 

}