.mich
{
 padding:15px;
 font: 15px Verdana;
 text-align:left;
 color:#333;	
}

ul {padding-left:15px;}

ul.circle {
 list-style-type: circle;
 margin-left:40px;
 padding-bottom:10px; 
 font-style:italic;
}

#ab {
  width: 30%;
  height:510px;
  border:0px solid yellow;
  background: url(ab01.jpg) center center no-repeat; background-size:cover;
  float:left;
  margin-right:4%;
  border:0px solid red;
}

.testo1 {}
.testo2 { width:66%; border:0px solid red;float:right; padding-bottom:20px; }



@media only screen and (max-width: 780px) {
#ab {
  width: 100%;
  height:250px;
  background: url(ab02.jpg) center right no-repeat; background-size:cover;
  margin:0 auto; float:none;
  }
.testo2 { padding-top:20px; width:96%;float:none;}
}