Tweak confirm donate message

[ajparsons]

This PR changes the confirm page to try out a 'help others' donate message, and tweaks to the display.

Happy for feedback this is the wrong visual approach, but I've:

• Removed the type writer background for clearer contrast - and added a slightly transparent black background for this.
• Slightly changed the donate green.
• Slightly longer and bigger donate message (anticipating we'll revisit this over time).

[dracos]

Not sure if it's worth putting the styling in the stylesheet (presumably changing hero-sent to remove the background image there but add the bits here), doesn't really matter. Check with Lucas if you want feedback on visuals?

[ajparsons]

Not sure if it's worth putting the styling in the stylesheet (presumably changing hero-sent to remove the background image there but add the bits here), doesn't really matter. Check with Lucas if you want feedback on visuals?

Yep, moved to the stylesheet while I'm editing it anyway.