gilby:
Whats the best way for a contrib?
I am working on a sidebox, the content of which needs to be centered or padded into the middle... Any guidelines on the best way to do it?
In regards to 1.3x based shops you have likely already located /includes/templates/template_default/css/CSS_read_me.txt. It does not directly respond to your inquiry but may help.
Assuming the mod is for 1.3x shops, and assuming the sidebox will display most/all of the time, and since you are only referring to one single style, adding the style to the main stylesheet is appropriate. Indeed if you expect the style will never ever require adjustment by the shop owner, you can "get by" with inline CSS or a separate style sheet. But these days I avoid inline when possible, even if "at first" it is most easy for me as developer, and you/me as shop owner. And I avoid going with a separate stylesheet, unless the style is only relevant to specific page(s) and/or is language dependent and/or the style does not need to be loaded constantly. Too many external style pages can become overly confusing.
On the contrary the default 1.3.0.1 stylesheet.css is 11KB (and likely larger if working on a heavily customized shop). And with separate stylesheets for third party mods, it is easy to identify/remove styles when/if the mod is ever uninstalled (rather than allowing the unneeded style info linger in the main stylesheet for eternity).
Opportunity costs in everything. So pick your poison ;)
Thanks to the updated div/id/class code in 1.3x, and with tools like Web Developer available, shop owners can now easily experiment with their shop CSS to match their creative desires. So when possible going the main stylesheet route is the way to go and generally pays off in the end if the custom style info is well documented within the stylesheet. (ease of maintenance).
Woody