Here iI will advice to fix this issue by addingusing the css injector https://www.drupal.org/project/css_injectorCSS injector module to add the necessary CSS styles to show an icon before the field label.
Allows administrators to inject CSS into the page output based on configurable rules. It's useful for adding simple CSS tweaks without modifying a site's official theme. The CSS is added using Drupal's standard
drupal_add_css()function and respects page caching, etc. The 2.x brach leverages CTools so CSS can be included with Feature changes (ie. CSS that improves the look of a View can be packaged with the View).
