ruby-overhang

The ruby-overhang CSS property specifies whether or not a <ruby> annotation overhangs any surrounding text.

The ruby-overhang property controls whether the ruby annotation text box (<rt>) may overlap adjacent text outside the <ruby> container box.

When ruby annotation text is not allowed to overhang — when ruby-overhang: none is set on the <ruby> element — that element behaves like an inline box, as if its display property were set to inline with only its own contents rendered within its boundaries and adjacent elements not crossing the boundary box.

By default, the content of an <rt> element is allowed to overhang, so content may overlap the <ruby> container box, partially rendering over or under surrounding inline-level content. With auto, the default, content may overhang, but it will not overhang if doing so would overlap adjacent <rt> elements or elements with a display value resolving to ruby-base or ruby-text.

Syntax example: ruby-overhang: auto;