There are various options for theming: You can create CSS rules on your local site that target the classes; you can include raw CSS below; you can also add your own CSS classes to certain elements below.
Add raw CSS here. Your mistakes are your own. Document structure:
div.inlay-update-giving
h2
div.test-mode
div.public-intro
div.confirm-user
div.current-giving
form.change-form
div.change-amount
label
input
div.change-go
button