Custom back button styling for a UINavigation bar.

gistfile1.css

.myLeftNavButtons {
  top             : 6;
  size            : 115 31;
  shape           : arrow-button-left;
  content-edge-inset : 0 0 0 6;
  font-weight     : regular;
  font-size       : 12px;
  color           : #ffffff;
  border-radius   : 3px;
  background-color: linear-gradient(#215a88, #4d93dd);
  border-width    : 1px;
  border-color    : #212325;
  box-shadow      : inset 0 1px 0 rgba(101,177,232,0.9),
                          0 1px 0 rgba(255,255,255,0.1);
}