function findClassesInStylesheets(classes) {
    'use strict'

    let regexClasses = classes.map(function (className) {
      let re = new RegExp('\\.' + className)
      console.log('created regexp', re)
      return re
    })

    var sheetCount = 0,
        ruleCount = 0,
        classCount = 0,
        testCount = 0,
        matchCount = 0;

    classCount = classes.length

    for (let i = 0; i < document.styleSheets.length; i += 1) {
      sheetCount += 1
      let cssRules = document.styleSheets[i].cssRules

      for (let j = 0; j < cssRules.length; j += 1) {
        ruleCount += 1
        let rule = cssRules[j]

        regexClasses.forEach(function (reClass) {
            testCount += 1

            if (reClass.test(rule.selectorText)) {
                matchCount += 1
                console.log('match found', reClass, rule.selectorText)
            }
        })
      }
    }

    console.log('Searched', classCount, 'classes in', ruleCount, 'rules from', sheetCount, 'sheets ')
    console.log('successful matches', matchCount, 'from', testCount)
}