I'm choosing the typefaces for a Web project (a library catalog), with the additional constraint that they have to be open source. So far, I've selected a typeface for the text: Clear Sans, from Intel. I think it is a pretty legible, neutral typeface and has a beautiful texture. I've considered other options like Open Sans, Roboto, Droid Sans and Ubuntu, but settled for Clear Sans. My problem is with the typeface for the headings. I've narrowed down my choices to two fonts: Amaranth and PT Sans, but I'm not quite sure which one to use. Amaranth is kind of an upright italic and I think it combines beautifully with Clear Sans, but I'm not quite sure it evokes the right mood. PT Serif is an old style serif that also combines quite well with Clear Sans, but the contrast between them is not as high as I would like. I've attached two samples of the combinations (the text is in Spanish). I'd like to hear your opinion and anything you have to say will be more than welcome. Thanks in advance!