title_body: Content Property in EPUB 2
upvoted_answer: EPUB 2 specifies content as supported property in the list of CSS properties.
  
  However, it is based on CSS 2.1, where the content property is allowed only for :before and :after pseudoelements. As the linked EPUB 3 spec shows (by linking to CSS 2.1), the same restriction applies in EPUB 3.
  
  Thus, the code in the question won’t work, to the extent that it relies on the content property. Moving the declaration to apply to a pseudo-element, if applicable, should work in conforming software:
  
  .TXBDINGBATS:before {
    content: "\2217 \a0 \a0 \a0 \a0 \a0 \2217 \a0 \a0 \a0 \a0 \a0 \2217";
  }