Use relative units like em with font-size

[thysultan]

Use relative units like 'em' with 'font-size' for better scaling support.

[ityler]

Agree with better scaling support. It's the only surface complaint I have regarding these icons in comparison to a typical "font" solution.

[wentin]

thanks for the suggestion! I will experiment and see if my concerns can be addressed (some css trick need specific exact value to work, and some relationship between elements need to be exact to look the way i want them to look)
This process reminds me of font hinting! lol

[LucaRosaldi]

+1 for this. Ems are definitely the way to go.

Quickly tried on codepen and it works fine: http://codepen.io/LucaRosaldi/pen/jrZVNW

[XiBOR]

Also you may use some keywords for better code integration, like color: inherit