Declare a size/partial border

gistfile1.txt

Method 1: http://dabblet.com/gist/e5a78f2d4bf50b6be4d3
CSS:
div {
	text-align:center;
}
  
h1 {
	position: relative;
	display: inline-block;
	color: #818488;
	font-family: "Century Gothic", CenturyGothic, AppleGothic, sans-serif;
}
h1:after {
	content: '';
	width: 75%;
	left: 12.5%;
	height: 1px;
	background: #b0b0b0;
	position: absolute;
	bottom: -1px;
}

HTML:
<div><h1>Something</h1></div>

Method 2:
http://dabblet.com/gist/1601054

CSS:
div {width:350px; height:100px; background:lightgray; position:relative; margin:20px;}
div:after{content:''; width:60px; height:4px; background:gray; position:absolute; bottom:-4px;}

HTML:
<div></div>