(Almost the) rest of the redesign (#880)

* Load demo img

* two-up styles

* Back button

* Button size tweak

* Move back btn

* Move options and back button into a single grid

* Simpler max height

* Responsive grid

* Feed index into options

* Option heading themes

* More option styles

* Changing checkbox position

* Theme range input & use transforms

* Range input underline theme

* Checkbox color

* Add toggle

* Reorder

* Arrow revealer

* Round two-up thumb

* Don't bundle CSS urls starting #

* Results in progress

* Fix Safari bugs

* Download blobs

* Loading spinner

* Hook up download button

* Different style for original image

* Mobile design for results

* Remove demo auto-loader

* Remove redundant colors

* Sticky headings

src/shared/prerendered-app/Intro/index.tsx

@@ -46,7 +46,7 @@ const demos = [
     url: logo,
     iconUrl: logoIcon,
   },
-];
+] as const;
 
 const blobAnimImport =
   !__PRERENDER__ && matchMedia('(prefers-reduced-motion: reduce)').matches