CSS border-width border-width : medium : See the Pen <a href="http://codepen.io/w3tr/pen/xOjwJk/">border-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/dXZYjN/">border-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/RRyWBk/">border-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/wWjKxX/">border-width length</a> by W3TR (<a href="http://codepen.io/w3tr">@w3tr</a>) on <a href="http://codepen.io">CodePen</a>.<br />