Very cool.

Small issue: I find that the cursor can be hard to use sometimes. For example, if I clear and then execute the single line

    "<style>body {background-color: #fdf6e3;}</style>"

I can no longer get an empty line at the bottom of the document. My cursor can only ever be within the outputted "<style>" tags, and hitting return from there creates a new pair of "<style>" tags.

To temper this bug-report with a cool feature, I like that the output is (usually, with the exception of the above) plain text, which can itself be executed. I haven't found a use-case for this, but I'm sure there's some interesting meta-programming that could be done.