In the event that you need to add custom css codes, you should add these codes into the custom.css file in your template folder to avoid your css changes to be overwritten when you upgrade.
To do so, you need to create a
custom.cssfile in the file path that looks similar as below./templates/YOUR_TEMPLATE_NAME/html/com_easysocial/css/custom.cssReplace YOUR_TEMPLATE_NAME with your current Joomla template folder.Once the file is created, you may start adding your codes into the file and the site will automatically render them on the page.