Fading out text on overflow with css if the text is bigger than allowed

Looks like your requirement is just to fade out the text beginning at a certain height (about 150px), the text (if any) presenting at that height is considered as overflow. So you can try using some kind of transparent linear gradient layer placed on top of the text area, we can achieve this in a neat way using the pseudo-element :before like this:

.row:before {
  content:'';
  width:100%;
  height:100%;    
  position:absolute;
  left:0;
  top:0;
  background:linear-gradient(transparent 150px, white);
}

Fiddle

I used this method derived from reddit pages & it works fine

.fade {
    -webkit-mask-image: linear-gradient(180deg, #000 60%, transparent);
  }

<div>
    <div class="fade">
    Text text text text<br />
    Text text text text<br />
    Text text text text<br />
    Text text text text<br />
    Text text text text<br />
    Text text text text<br />
    Text text text text<br />
    Text text text text<br />
    Text text text text<br />
    Text text text text<br />
    </div>
</div>