Seems nice and simple, good job! Some comments/suggestions:
* There seems to be no <title> tag on the page, or at least I don't see a title for the page.
* When the browser downloads the output, it is served to it as a "binary file" (Firefox on Mac), not PDF, meaning I have no other option than to download it. I think (though I'm not sure) that if you set the content type correctly it could open straight in a new tab, or at least let me open it straight in a PDF viewer.
* The paper format looks a bit off to me, I guess it's because it's letter? In that case, not everyone uses that (we use A4), though lettings users set it would increase UI complexity.
* There seems to be no <title> tag on the page, or at least I don't see a title for the page.
* When the browser downloads the output, it is served to it as a "binary file" (Firefox on Mac), not PDF, meaning I have no other option than to download it. I think (though I'm not sure) that if you set the content type correctly it could open straight in a new tab, or at least let me open it straight in a PDF viewer.
* The paper format looks a bit off to me, I guess it's because it's letter? In that case, not everyone uses that (we use A4), though lettings users set it would increase UI complexity.