I can change fontcolor, but not the \"fill\". I first tried setting background-color, but that fills the whole icon box area.
For example, I have
All you need is to set color: yellow. Because the icons are a font, they will take whatever colour you'd set to any other font (text) in the same way.
if you want to fill the whole star as yellow, try icon-star instead of icon-star-empty
you can try this
-webkit-text-stroke-width: 1px;
-webkit-text-stroke-color: orange;
to add stroke (outline) to the font itself. I hope thats what you are looking for.
and to fill it just use the normal
color: yellow;