There comes a time when we figure who our real friends are. If you’re 30, chances are you’ve already reached this point. If so, then your birthday invitation doesn’t have to be flashy or attention-grabbing. It’s not a flyer; it’s more of a reminder. So it’s fine to go with a design that’s more subtle or subdued. Try this mature blue-green color scheme and refined off-white background. Then top it off with a modern art motif combined with a minimalist sans serif font.