<hr> – Horizontale Linien und Trenner
»Flat design vector concept« von Shutterstock

CSS Code Snippets

<hr> – Horizontale Linien und Trenner

border: 0;
height: 1px;
background: -webkit-linear-gradient(left, transparent, rgba(0, 0, 0, 0.5), transparent);
background: linear-gradient(left, transparent, rgba(0, 0, 0, 0.5), transparent);
margin: 35px 0 33px 0;

Source: http://css-tricks.com/css-tricks-chronicle-xxi/