I wrote this guide with the intention that it would cover everything I have to share about HTML and CSS in regards to writing CSS for deviantART jorunals - but it would have been outside the initial scope to include everything on HTML and CSS. For those that do want to learn everything there is to know about HTML and CSS, I've collected the following helpful resources.
Additionaly I've linked to tutorials and resources about writing journal skins written by other members of deviantART. While I'd like to think Creative Journal CSS covers everything you'd need to know, it's really only everything I know, written in the way my mind works. You might have better luck learning through someone elses teachings. Even if you find success after reading my guide, you will still find benifit in reading those by others too.
Note that this guide is not specificaly for deviantART, it is about CSS in general, so it mentions some things (particularly id's) that we can't use on deviantART - but it's still well worth reading.