multiple values for FONT similar to font-family

Hi,
I am hopping this is the correct place for CSS3 suggestions. I am pretty sure I cannot be the only one who needs this but just in case. Can you please add multiple values for font so in case of fallback it will choose other font sizes as well.
For example:
font: 1em "Calibri Light", 0.9em Arial, sans-serif; so when browser cannot find the calibri it uses Arial but instead of 1em this time 0.9em as the size of Arial is different.
this will have perfect for responsive design 
Best regards.Onur Topal