I don't know the particulars for FA uniforms, but stripes their widths, location and colors usually indicate rank or position and service longevity on uniforms. Airline uniforms were originally based on military service uniforms, and they follow many of their peculiarities.

I am curious if a name tag is a mandatory or optional uniform item, as on a recent flight, punctuated by unsatisfactory service, the FAs in the F cabin declined to wear name tags - it almost made me think one FA was already planning her indiscretions, or at least knew enough of her poor service record she plans to avoid getting written up. (This flight was very unlike the vast majority of AA flights I have enjoyed good to excellent service on.)