Subscript is not being styled

[HerbCaudill]

See the last paragraph under https://book.keybase.io/docs/teams/puk#cryptographic-specifics for example.

On book site, subscripts are styled as normal text.

On docs site, subscripts are styled correctly.

[shiflett]

Yeah, it looks like the markup is correct, and we need a style defined for <sub>:

Also, whenever the key rolls over, the previous seed <em>s</em><sub>i</sub> is encrypted with <em>c</em><sub><em>i</em>+1</sub>