Den Customization Not Applying

Ran the code through Stylus and CSSLint, no errors are being found. Warnings, but no errors that break the code. Everything appears functional on Stylus, yet when I attempt to actually apply the code to my den, nothing is happening. I'm not finding any breaks manually either.

I'm not sure at this point if it is a issue of how I'm applying the code, or the code itself. Since I plan on this being a F2U CSS, just doing it for re-introduction to coding mostly, I don't mind if ya'll take a look at the code itself as well. HERE

Here is how I'm applying the code to my den:

<link rel="stylesheet" type="text/css" href="https://www.dropbox.com/s/cxc02g7etw8dfzv/Blue%20Pattern%20WD.css?dl=0">

Hello, I think you put the wrong link in, it redirects to this chatter page rather than the dropbox. Don't know if that was intentional, but just thought i'd let you know!
Also, I am by no means an expert in code, heck I barely have any experience, but from my trials of messing around with it yesterday, I'd recommend adding < style > at the beginning and < /style >  at the end (remove the spaces, had to add them so they would show up). When I put those in the code and put it in my den desc, everything showed up, although you'd have to check yourself to see if it's all correct. Hope this helps, honestly I have no idea if it'll work lmao but it's worth a shot!

Gave it a shot, but still nothing. I'm stumped...

Tried it on my other devices (I have HP laptop, Apple tablet and a Samsung cell) and still nothing. I am able to upload other folk's codes no problem, so I'm not sure what's going on.

Here's (hopefully) the correct link: https://www.dropbox.com/home/Free%20to%20Use%20CSS?preview=Blue+Pattern+WD.css