body{
    font-family: Helvetica, Arial, sans-serif;
    margin: 0 auto;
    width: 700px;

}
/*
div #post-list
ul .clase
*/
header, footer{
    background-color: rgb(70, 70, 80);
    color: white;
    border-radius: 5px;

}
a{
    color: green;
}
#main{
    background-color: rgba(120, 120, 50 , 0.5);
    min-height: 400px;

}
#post-list{
   float: left;
   background-color: #5Fe;
}

#ads{
    float: right;
    background: #e5F;
}

footer{
    clear: both;
}