attempt at multiple loop with in_category

Hi guys,

I’d like to change the multiple loop in TwentyTen to a very simple one where I can use in_category to define a few variables in the design of posts (borders, fonts).

I’ve come up with this so far:

[Code moderated as per the Forum Rules. Please use the pastebin]

Are my endifs and endwhiles in the right place? Is it correct of me to assume I can add classes to my child theme stylesheet to alter fonts etcetera for the content?

In the end, the three categories will turn up as posts on three pages, each accessed from my menu.