CSS Ruby is a module of CSS that provides the rendering model and formatting controls related to display ruby annotation, a form of interlinear annotation, short runs of text alongside the base text.
The ruby-position CSS property defines the position of a ruby element relatives to its base element. It can be position over the element (over), under it (under), or between the characters, on their right side (inter-character).
The ruby-align CSS property defines the distribution of the different ruby elements over the base.