Override Theme CSS

At the moment, the plugin will get the layout and style of your theme. In your case, you can override the CSS via the style.css file of your theme or create a folder with name: dwqa-templates 
then create a style.css file in this folder. 

Also, you need to add the following code to the functions.php file: 

/* load style for DW Q&A plugin */
if( !function_exists('dwqa_dom_amor_scripts') ){
function dwqa_dom_amor_scripts(){
wp_enqueue_style( 'dw-dom-amor-qa', get_stylesheet_directory_uri() . '/dwqa-templates/style.css' );
}
add_action( 'wp_enqueue_scripts', 'dwqa_dom_amor_scripts' );
}

I have checked your site and see that you have removed the plugin then I have installed the plugin to check the issues. After activating the plugin I see that the plugin working and look good now.
I think you have some confuse in the configure of the plugin. 
Please check and let me know if you have any issue.