html - Absoloute position div to bottom of relative parent -

i'm trying place 'blue' @ bottom of parent container 'green'. i've tried following this answer, can't work. want blue div @ bottom of green div.

#green {  	position:relative;  	width:auto;  	height:200px;  	background-color:green;  }          #blue {  	position:absoloute;  	bottom:0;  	height:75px;  	width:auto;  	background-color:blue;  }

<div id="green">  	<div id="blue"></div>  </div>

thanks.

1- need change position absoloute absolute of #blue, after width auto width 100%.

#blue {     position: absolute;     bottom: 0;     height: 75px;     width: 100%;     background-color: blue; } 

here working example http://codepen.io/saorabhkr/pen/boqjvn