The OP asked for feedback, and I figured it was better he heard it from me than from 37signals' lawyers. It doesn't look like 37 signals has trademarked that p

The OP asked for feedback, and I figured it was better he heard it from me than from 37signals' lawyers. It doesn't look like 37 signals has trademarked that particular color scheme or design, and I don't see any evidence that they own or have an exclusive license to the font in question; so there really seems to be no legal concern here at all.