This skin is now too buggy to use. I do not recommend you install it.
I'll be writing a new version for deviantART v6.x eventually, but these things take up so much time and effort that I'm not that motivated right now.
If someone wants to put forward a donation to motivate me to update the skin now, well, I wouldn't say no to that, but otherwise you'll just have to be patient.
STEP ONE: Visit dA5pook Black @ userstyles.org and see the section titled 'Install options'. Firefox users will see a button that reads 'Load into Stylish' or 'Update in Stylish' if you've got it installed already. If you don't have Stylish, get it.
Alternatively, if you know what you're doing, you can @import it from http://devart.koopseht.net/skins/black/
If you're a Firefox user still using DeviantSkin to install your skins - disable/uninstall any skins you have, uninstall DeviantSkin and start using Stylish instead. DeviantSkin was awesome when `bluespeed9 first published it, but to compare it to Stylish would be like comparing IE with Firefox.
If you use Opera, you can still install it, though you'll probably need to edit the skin beforehand (to remove the Firefox only @-moz-document bits. I've only tested the skin in Firefox.
If you still use IE - got cry to mommy, you're not ready to use the internet.
STEP TWO: Install the following Greasemonkey script - noCSSForJournals.user.js - it's a helper script that makes sure journals look pretty. If you don't have the Greasemonkey extension installed, click the link and get it.
You could get away with not installing the script, but some journals (those without CSS) might be hard to read or look wrong. So, INSTALL IT!