bbcode font-size semantics

[PinkMilk]

Thanks but that's not what I mean, converting sizes to Points/Pixels/Ems is the easy part, I'm needing to change how vbulletin converts the members bbcode choice:

PHP Code:

html' => '<span style="font-size:%2$spx;">%1$s</span>, 


Rather than:

PHP Code:

html' => '<font size="%2$s">%1$s</font>, 


Now one way I guess would be to add a "1" before the replace var turning 1 into 11, 2 into 12 etc etc

html' => '<span style="font-size:1%2$spx;">%1$s</span>,

..but I would still like to know where in vbulletin the font-size function, CSS or whatever is allowing me to choose specifically which font sizes I wish whether it be within a template or php file as I can't find where myself.