.icon-envelope { background-image: url(png/envelope.png); background-repeat: no-repeat; }

.icon-facebook { background-image: url(png/facebook.png); background-repeat: no-repeat; }

.icon-menu { background-image: url(png/menu.png); background-repeat: no-repeat; }

.icon-twitter { background-image: url(png/twitter.png); background-repeat: no-repeat; }