Thick underline behind text

Question

How to reproduce this sort of underline behind the text ABC using spans and css?

Answer 1

http://codepen.io/OxyDesign/pen/eHAac

With :before in absolute position

CSS

.underlined-text {
  font-size:100px;
}
.underlined {
  display: block;
  float:left;
  height:92px;
  position:relative;
}
.underlined:before {
  display: block;
  content:'';
  position:absolute;
  width:100%;
  bottom:0;
  left:0;
  background:#f66;
  z-index:-1;
}
.underlined.first:before {
  height:15px;
}
.underlined.second:before {
  height:30px;
}
.underlined.third:before {
  height:45px;
}