Adding a text resizer control for visitors?

I need to make a text resize tool available to visitors who are visually impaired. It’s a requirement of local accessibility laws, and needs to affect all text elements on the page.

It’s a very simple site. Header is logo graphic, all pages use 2 column layout (primary sidebar at right) with 1 footer widget space.

I’ve read the documentation, gone several months back in this support forum, and Googled for hours. All I’ve found are a few plugins that either seem abandoned, or are exhibiting some scary issues.

Am I missing something simple? It seems weird that such a common task on such a common platform wouldn’t be crawling in solutions.

Does anyone have a simple and stable solution in place for this? Or a suggestion of somewhere else I should be looking?

Thanks very kindly!