Specifies the horizontal alignment of the Ruby text defined by the rt tag, relative to the base text defined by the ruby tag.
Default. Browser determines how the Ruby text (rt) is to be aligned.
The Ruby text rt is centered within the width of the base ruby's content.
If the width of the Ruby text (rt) is smaller than the width of the base ruby's content, then the Ruby text (rt) is evenly distributed across the width of the base content ruby.
If the width of the Ruby text (rt) is smaller than the width of the base ruby's content, then the Ruby text (rt) is centered and the left/right margin is filled up with whitespaces.
The Ruby text rt is aligned to the left of the contents of the base ruby.
If it is not adjacent to a line edge, the Ruby text is centered.
The Ruby text rt is aligned to the right of the contents of the base ruby.