FreeCodeCamp

Update bootstrap.json

fixed line 1886, changed col-xs-12 to col-xs-6
"assert($('.col-xs-6').children('h4') && $('.col-xs-6').children('h4').length > 1, 'Add an <code>h4</code> element to each of your <code>&#60;div class=\\'col-xs-6\\'&#62;</code> elements.');",