This issue is applicable to most languages.

Text that is normally written horizontally may need to be written vertically for special effects (the spine of a book, table column headings, etc). Typographically, it is simply horizontal text that is rotated.

The GAP

The CSS feature defined in Writing Modes Level 4, which is in CR, provides a solution using sideways-lr|sideways-rl values of the writing-mode property.

There is no way to do this effectively until browsers support the new CSS properties.

writing-mode:vertical-lr/rl is not appropriate for achieving this, because of things such as wrong locations for line start and end, and incorrect direction of line wrapping, not to mention the implications for glyph rotation.

Only Gecko supports these values. Blink and WebKit do not.

Priority

Support is needed sooner rather than later, since people are writing tutorials or explainers that show how to do this using the currently supported writing-modes values. However, the currently supported values only work properly for CJK languages, and produce incorrect results for normally horizontal scripts unless used in the simplest way possible (for example, line breaking and text alignment break things).

The sideways values were moved from CSS Writing Modes 3 to level 4 because implementation support was there for the values needed for CJK. However, CSS Writing Modes 4 went to CR almost immediately with the expectation that support for the sideways features would follow soon.

Tests & results

interactive test, sideways-rl is supported in browsers

interactive test, sideways-lr is supported in browsers

Action taken

Chromium • WebKit

Outcomes

With the release of Safari 18.4 all major desktop browsers now support the sideways values of writing-mode.