I think blue looks good, but you should use the image data URI scheme to encode the image so that everything is in a self contained html page like the original page.
This is somewhat off-topic, but has anyone considered refactoring the code to have the pieces split into separate files that are built into one big file for release? I think it is a bit unmanageable with all the scripts, CSS, base64 images in one huge file, with deeply-nested indentation. I might have done it earlier, but didn't want to waste the time if pointbiz rejected it for whatever reason.
The encryption/decryption is implemented asynchronously, so when the unit tests run, the browser will be trying to perform 6 decryptions and 4 encryptions from the official test vectors and 2 random encryption-decryption cycles, all at once!
Author of the decryption code for Casascius' bounty here. I enjoyed having them all run concurrently on my 8-core machine, others may not like it so much.
It should be possible to chain the asynchronous tests so they run serially, and they probably should be chained into the standard tests so the alert at the end can mean the async tests passed too. (There could also be a flag to force scrypt to run synchronously for the tests, but then I would worry about the web-worker asynchronous version not being tested.)