B-side CSS audit: Removed defunct styles, revised comments, more logical selectors.
Fix HTML comment so you can copy-n-paste 'encrypt failed' and 'decrypt failed' into the <form> class attribute when you are previewing a screen design.
Filled in the hidden input name in the default HTML to be consistent and reduce confusability and to illustrate how things are actually meant to work.
Removed defunct 'message' class on encrypting and decrypting status text.