I see the difference you pointed out (the "p" and the "h1" ids) but I'm really working with a grandchild theme. (Cataylst is the parent theme, Dynamik is the child theme and my custom.css file (I suppose) would be the grandchild theme. Since I'm already working two tiers removed, I don't know how to remove the <p id="title"> and wrap it in h1#tagline without manipulating the parent theme (sorry, I don't know exactly how to ask this question, I hope you know what I mean).
As a more immediate (but not proper, I don't think) solution, if I just comment out the /*line-height:155%;*/, then the #tagline style is the same for both and I can adjust the top margin. ...is this what I should do? (it works, I just don't think it's the right way to go).