Ebook reading systems support a fairly limited subset of HTML and CSS. Of particular relevance, most of them do not support the advanced CSS selectors like the type being used in the checkbox hack that you link—there's no selecting the adjacent sibling.
The only other option that I can think of is epub 3.0's
epub:trigger. Unfortunately, at present that only allows you to toggle
visibility:hidden and not
display:none, which means the space the invisible paragraphs take up will still be there, so you'll have giant translation-sized holes in your text. Even if the IDPF adds a
display control to