It’s possible to specify the writing direction in both user-defined classes or in-line using the <span> tag. Specify writing-mode: vertical-rl; to make it vertical. Specify the orientation using the transform: rotate(90deg); in the unit of 90 degrees to rotate text. But even if ‘writing-mode’ and ‘reference-orientation’ are specified, if you don’t make it right, it will not be effective.