Welcome the Technical Support section. Help us in assisting you by providing us with a concise and descriptive elaboration of your issues. Be specific and if possible, provide us with a step-by-step instruction in replicating your problem.
in /components/com_community/templates/default/css/style.css
you can find the following and edit it using an override or directly in the file but remember your change will be gone if directly edited and the file is changed during an upgrade