Example of different CSS Call

Here we demonstrates two examples of css call, The blue square is the result, the red one the css lines needed

#pp_menu {float:left;width:150px;padding:10px;height:180px;background-color:#aa0022;}
#pp_menu .img {float:left;margin-right:10px;width:50px;height:50px;background-color:#aaffaa;}
#pp_menu .txt {font-weight:bold;}
#pp_productList {float:right;width:300px;background-color:#ffcc00;height:180px;padding:10px;}
#pp_productList .produit {background-color:#ffffff;overflow:hidden;margin-bottom:10px;padding:10px;overflow:hidden;}
#pp_productList .produit .img {float:left;width:45px;height:45px;margin-right:10px;background-color:#cc22aa;}
#pp_productList .produit .txt {float:left;width:150px;margin-right:10px;}
#pp_productList .produit .price {float:left;color:blue;}

#pp_menu {float:left;width:150px;padding:10px;height:180px;background-color:#aa0022;}
.pp_img_menu {float:left;margin-right:10px;width:50px;height:50px;background-color:#aaffaa;}
.pp_txt_menu {font-weight:bold;}
#pp_productList {float:right;width:300px;background-color:#ffcc00;height:180px;padding:10px;}
.pp_produit {background-color:#ffffff;overflow:hidden;margin-bottom:10px;padding:10px;overflow:hidden;}
.pp_img_produit {float:left;width:45px;height:45px;margin-right:10px;background-color:#cc22aa;}
.pp_txt_produit {float:left;width:150px;margin-right:10px;}
.pp_price_produit {float:left;color:blue;}