I emailed the HR lady and she just said black or khaki pants and a white or black shirt. Pretty simple. She didn't say anything about tattoos or piercings. I have a number of ear piercings and my nose pierced, and 1 tattoo (though that's on my foot, so it's generally covered by shoes).
Sucks that you can't wear any colors. I am a person that does color all day every day. Guess I'll have to get some fun colored hair ties and headbands. And maybe a fun colored pair of shoes since she said any color shoes are fine as long as they aren't sneakers.