wufoo form is not working with my CSS file in pastebin

I'm trying to connect in the themes section of wufoo my .css file, but it has no effect.

The css code is available here and the this is my form.

To test it, I'm trying to put a blue header and a red label

.wufoo .info h2 {
  color: blue;
}

.wufoo label.desc, .wufoo legend.desc, .likert caption {
  font-size: 95% !important;
  font-family: inherit;
  font-style: normal;
  font-weight: bold;
  color: #ef0000 !important;
}

1. Create your CSS file and save it with a .css extension. Save this file in the Dropbox folder on your computer or upload the file using the Dropbox web app.

2. Navigate to the file you saved in the Dropbox web app. Click the 3 dots on the right side of the file and choose Share. Click Create Link then Close. If you are using Dropbox Business or Professional, you will also need to click Link Settings and change the Link Access setting to Anyone.

3. Head over to your Docs Settings page and click into the Custom Code section. Paste the URL you just copied into the Custom Stylesheet URL field.

But wait, there's more! This next part is super important!

The link you just pasted looks something like this: https://www.dropbox.com/s/19kh2r77nipor2w/test.css?dl=0

You need to change the www in the URL to dl, and remove the ?dl=0 from the end so it looks like this: https://dl.dropbox.com/s/19kh2r77nipor2w/test.css

This allows Docs to access the source of the file rather than the Dropbox page for the file. Click the Save button at the bottom of the page when you're finished.