Credits

Blue Sun Background Tiles (on the old CSS): From here
The current background on the default CSS is an edit of a background from Pesterquest. The original image was drawn by the legendary Xamag!
Pink Cat Background Tiles: Cairovercoat and Cinnamonbird, plus some custom editing in MS Paint.
Green Sburb/Sgrub tiles: also Cairovercoat!
The Wood Tile Background is from here.
The Neocities button is from Neocities, obviously. I forgot where I found the one used on the pink CSS test page, but might have been another site here.
The "under construction" gif on many pages was found via A.N. Lucas's lounge.
The comic pages 0 and 2 are from XKCD and MS Paint Adventures, respectively. I just used them as example images.
The pixel art cherry tree, fish pond (both), and city backgrounds on various test pages are all by the amazing 1041uuu!
The background image of the Alternian page is from Hiveswap Friendsim, and was obtained from Eldritchdraak's Hiveswap Asset Rips.
All pictures and videos on the 'cute' page link back to their sources unless otherwise specified.
The header image for the Golden Sun page was made using this image from the wiki.
Jade Harley stuff is mostly credited on the pages.

The background of Tall Sidebar Test is from the Pesterquest backgrounds from Jade's route.
The current background of the actual Jade Pages CSS (both old and new) is a custom edit of cairovercoat's godtier space background.

I wrote the code for this site myself, but made heavy use of W3 CSS's guides and tutorials. They're super useful, and you're new to this, you should check it out! :D
This stackexchange thread for information and code for text-shadow. Don't remember if I actually used it or not, but it's probably worth linking.
The table of contents on my page for Alternian uses CSS list code from this stackexchange thread. (I used the second answer's code.)

The Alternian Script font comes from Hiveswap, and the font itself was put together by the amazing OrangeyPeels on Deviantart!
The "Friendsim" font (Berlin Sans FB) was found via Eldritchdraaks, and downloaded from AZFonts

HTML Color Codes was really useful for finding colors for this site.
Some of the other color palettes used here were made from various pretty images using Canva.com's color palette generator. It's really cool!
The placeholder text on most pages is from Neocities.
I used this site for the Lorem Ipsum text, both with the original couple paragraphs and a gibberish generator! It's pretty cool.
A few pages use text from the first chapter Lewis Carrol's "Alice in Wonderland" as sample text.
One of the CSS sample pages uses two lines from Owl City's "Fireflies", for some reason? Why did I do that. I don't know.
The style and format of fanfiction in the Jade Pages CSS 3.0 is heavily based on (and basically uses the rating system of) Archive Of Our Own, a large and popular fanfiction archive.
The two alternate Alternian fonts were made using a font-making site called Calligraphr.
This is just a cool site, and might be useful for you.

Other stuff not listed here is probably mine! :)