Staggering <ruby> tags

[patarapolw]

Recently, I came across that, it is possible to stagger Furigana, like this 東とう南なんたつみの方角

<ruby><ruby>東<rt>とう</rt>南<rt>なん</rt></ruby><rt>たつみ</rt></ruby>の方角

Also, even already with Furigana, adding emphasis dots should also be possible - 危き険けん、、な 、秘ひ密みつ、、を 、