CSS3 Writing modes section

writing-mode: horizontal-tb
Latin based: left-to-right inline direction with a downward (top-to-bottom) block flow direction

writing-mode: vertical-rl
Han-based: top-to-bottom inline direction with a leftward (right-to-left) block flow direction

writing-mode: vertical-lr
Mongolian-based or Manchu-based: top-to-bottom inline direction with a rightward (left-to-right) block flow direction