CSS Writing Modes is a CSS module that defines various international writing modes, such as left-to-right (e.g. used by Latin and Indic scripts), right-to-left (e.g. used by Hebrew or Arabic scripts), bidirectional (used when mixing left-to-right and right-to-left scripts) and vertical (e.g. used by some Asian scripts).
The text-combine-upright CSS property specifies the combination of multiple characters into the space of a single character. If the combined text is wider than 1em, the user agent must fit the contents within 1em. The resulting composition is treated as a single upright glyph for layout and decoration. This property only has an effect in vertical writing modes.
The text-orientation CSS property defines the orientation of the text in a line. This property only has an effect in vertical mode, that is when writing-mode is not horizontal-tb. It is useful to control the display of writing in languages using vertical script, but also to deal with vertical table headers.