add note about accessibility to README

.gitignore

@@ -28,3 +28,4 @@ yarn-error.log*
 
 # cypress
 cypress/videos/*.mp4
+cypress/screenshots/*

README.md

@@ -28,6 +28,13 @@ For better or worse, using BEM to keep CSS manageable. This may be overkill sinc
 
 The CSS font-face does not seem to apply if fonts are loaded by the Shadow DOM's styles, so a separate font stylesheet is provided for these.
 
+# Accessibility
+
+To allow this calculator to be embedded on state government websites, we require compliance with WCAG 2.1 AA accessibility guidelines.
+We use `cypress-axe` to maintain a baseline of automated conformance, and periodically review against a
+[Voluntary Product Accessibility Template](https://www.itic.org/policy/accessibility/vpat) for steps that can only be assessed manually.
+Any significant UI changes or additions will need to be manually reviewed against the VPAT.
+
 # Hosting
 
 This site is deployed using the [embed-rewiring-america](https://vercel.com/rewiring-america/embed-rewiringamerica-org) project on Vercel. The domain `embed.rewiringamerica.org` points to Vercel and is [configured in Google Domains](https://domains.google.com/registrar/rewiringamerica.org/dns).

cypress/e2e/state-calculator.cy.ts

@@ -2,15 +2,17 @@
 /// <reference types="cypress-axe" />
 
 describe('template spec', () => {
-  beforeEach( function () {
+  beforeEach(function () {
     cy.visit('http://localhost:1234/rhode-island.html');
 
     // Inject the axe-core library
     cy.injectAxe();
   });
 
   it('Has no detectable a11y violations on load', () => {
-    cy.checkA11y();
+    cy.checkA11y(null, {
+      runOnly: ['wcag2a', 'wcag2aa'],
+    });
   });
 
   it('renders the calculator', () => {