.container{
  width: 960px;
}
#main_content{
  width: 740px;
  padding-top: 10px;
}
#sidebar{
  width: 180px;
  margin-left: 25px;
  padding-top: 10px;
}
@media screen and (max-width: 896px){
  .container{
    width: 100%;
  }
  #main_content{
    width: 100%;
  }
  #sidebar{
    width: 100%;
    margin-left: 0px;
  }
}