.main {
  padding:10px;
  float:left;
  width:60%; /* The width is 60%, by default */
}

.right {
  padding:10px;
  float:left;
  width:40%; /* The width is 20%, by default */
}

/* Use a media query to add a break point at 800px: */
@media screen and (max-width:800px) {
  .left, .main, .right {
    width:100%; /* The width is 100%, when the viewport is 800px or smaller */
  }
}
.network {
  width:700px; 
  height:250px;
}
@media screen and (max-width:800px) {
.network {
  max-width:100%;
  display:block;
  height:auto;
}
}