html
{
    margin:0;
    padding:0;
}
body {
}
.Contenedor
{
    width:80%;
    max-width:1000px;
    margin:0 auto;
    overflow:hidden;
}
.main{
  width:70%;
   padding:20px;
    float:left;
    box-sizing:border-box;
}
.main img{
    width:100%;
    height:auto;
}
/*@media screen and (max-width:800px){
    body{background:#4cff00;}
}*/
@media screen and (max-width:800px){
    .Contenedor{width:100%;}
}
@media screen and (max-width:800px){
    .main{width:350px;}
}