CSS border-bottom-width border-bottom-width : medium : See the Pen <a href="http://codepen.io/w3tr/pen/qNYbop/">border-bottom-width: medium</a> by W3TR (<a href="http://codepen.io/w3tr">@w3tr</a>) on <a href="http://codepen.io">CodePen</a>.<br /> thin : See the Pen <a href="http://codepen.io/w3tr/pen/oLdbqq/">border-bottom-width: thin</a> by W3TR (<a href="http://codepen.io/w3tr">@w3tr</a>) on <a href="http://codepen.io">CodePen</a>.<br /> thick : See the Pen <a href="http://codepen.io/w3tr/pen/PzZkRL/">border-bottom-width: thick</a> by W3TR (<a href="http://codepen.io/w3tr">@w3tr</a>) on <a href="http://codepen.io">CodePen</a>.<br /> length : See the Pen <a href="http://codepen.io/w3tr/pen/rLvxvL/">border-bottom-width length</a> by W3TR (<a href="http://codepen.io/w3tr">@w3tr</a>) on <a href="http://codepen.io">CodePen</a>.<br />