Address CSS linting issue assets/css/src/amp-default.css  76:37  ✖  Expected double quotes   string-quotes Simply change the ' to ".
Address CSS linting issue
assets/css/src/amp-default.css
 76:37  ✖  Expected double quotes   string-quotes
Simply change the ' to ".

ampproject/amp-toolbox-php,ampproject/amp-toolbox-php