Ok so first off you need to understand that everything you see in front of you is divided into lots and lots of templates (you can argue that vB is a dumb **** and most of these are useless and unnecessary, but sadly we can't do anything about that). These templates define layouts of certain areas within the webpage, such as the
postbit template, the
forumhome template, or the
header template.
When you load up the PC index.html page, that html doc contains variables and directories to all sorts of templates that are loaded into the page to form the site that you see.
Now, there's no necessary tool for creating styles, but since PC has made numerous edits and changes to many templates that we want to appear throughout all of our styles, we've (or rather the administration) created a Master Style. All other styles are child-skins from the Master Style (it's an option in ACP, wherein the child-style inherits all template changes from the mother-style aka the Mater Style in our case). You'd need to get access to that first before making a skin.
Now, last I checked we didn't have access to the Master Styles because of the internal works going on right now. Idk.
Furthermore, you'd need a vB test board where you have access to ACP and can work on the skins from there. I think there may be other methods, but idk.
As for necessary knowledge, you'd need to know CSS in order to make the simplest edits. HTML is required if you want to go ahead and edit the templates thus changing certain layouts like the position of the linkbar or adding a side-bar... etc. And Javascript or Ajax would be necessary for adding such features as an animated dropdown menu or animated expandable panel or w/e.
Resources:
HTML Tutorial
CSS Tutorial
Javascript Tutorial
Interactive Javascript Tutorial
