Add pa11y and fix accessibility issues

accessibility.js

@@ -0,0 +1,55 @@
+const pa11y = require('pa11y')
+const chalk = require('chalk')
+const puppeteer = require('puppeteer')
+
+const check = async (browser, theme) => {
+  console.log(chalk`{bold Checking {blue ${theme}} theme...}`)
+
+  const page = await browser.newPage()
+  page.emulateMediaFeatures([
+    { name: 'prefers-color-scheme', value: theme }
+  ])
+
+  const results = await pa11y('./dist/docs/index.html', {
+    ignore: [
+      'WCAG2AA.Principle3.Guideline3_2.3_2_2.H32.2' // Ignore "this form does not contain a submit button"
+    ],
+    browser,
+    page
+  })
+
+  if (results.issues.length === 0) {
+    await page.close()
+    console.log(chalk`{green No issues found!}`)
+    return false
+  }
+
+  for (const issue of results.issues) {
+    console.log()
+    console.log(chalk`{red Error:} ${issue.message}`)
+    console.log(chalk`{gray -> ${issue.code}}`)
+    console.log(chalk`{gray -> ${issue.selector}}`)
+    console.log(chalk`{gray -> ${issue.context}}`)
+  }
+
+  await page.close()
+  return true
+}
+
+const go = async () => {
+  try {
+    const browser = await puppeteer.launch()
+
+    const lightResult = await check(browser, 'light')
+    console.log()
+    const darkResult = await check(browser, 'dark')
+
+    await browser.close()
+    if (lightResult || darkResult) process.exit(1)
+  } catch (error) {
+    console.log()
+    console.log(chalk`{red An unexpected error occured!} ${error.message}`)
+  }
+}
+
+go()