Use Unicode characters instead of multiple latin letters: Ⅰ instead of I, Ⅱ instead of II, Ⅲ instead of III, Ⅳ instead of IIII and Ⅴ instead of IIIII.

While non-subtractive forms like "IIII" are allowed at least "IIIII" becomes even more uncommon. If you argue with https://tracker.phpbb.com/browse/WEBSITE-1066 then I have never seen a clock that not uses Ⅴ. I'm refering to https://www.phpbb.com/downloads/3.0/ where (in contrast to https://www.phpbb.com/downloads/3.1/) "I" to "IIIII" appears (not only "I" to "IIII").

Or just use proper HTML/CSS:

list-style-type: upper-roman