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Proposed solution attached. NOTE: this may need some additional CSS. I may add that after additional testing by team's QA.

Thanks @JasonSafro this looks like a welcome change that we'd want to add.

I think the only update I'd ask for is to make sure that when the custom text option is used, that we filter the text with the "plain_text" filter to make sure there are no XSS issues with user entered text. Otherwise changes look good.

Depending on the CSS changes, if they are things that a theme should be responsible for, we shouldn't worry about that with the module.