The codes have to be added to the end of the functions.php file of your WordPress theme.
By doing so your changes will not be overwritten when you install a new version of Social Login.

********************************************************************************
* Use your own CSS
********************************************************************************
 
 function oa_social_login_set_custom_css($css_theme_uri)
 {
 	//Replace the URL by an URL to your own CSS Stylesheet
	$css_theme_uri = 'http://public.oneallcdn.com/css/api/socialize/themes/buildin/connect/large-v1.css';
	
	//Done
	return $css_theme_uri;
 }
 add_filter('oa_social_login_default_css', 'oa_social_login_set_custom_css');
 add_filter('oa_social_login_widget_css', 'oa_social_login_set_custom_css');


********************************************************************************
* Restrict access and allow only email addresses of a specific domain
********************************************************************************

function oa_social_login_filter_new_user_email ($user_email)
{
	//Only users with social network accounts having an email address ending in @gmail.com may register
	if ( ! preg_match ('/@gmail\.com$/i', trim ($user_email)))
	{
		return 'disallowed';
	}
	return $user_email;
}
add_filter('oa_social_login_filter_new_user_email', 'oa_social_login_filter_new_user_email');


********************************************************************************
* Custom redirections
********************************************************************************

//Redirection for new users
function oa_social_login_filter_redirect_for_new_users ($url, $user_data)
{
	//Force the url to something else
	$url = 'http://my-website.com/welcome-new-user/';

	//New users will be redirected here
	return $url;
}
add_filter('oa_social_login_filter_registration_redirect_url', 'oa_social_login_filter_redirect_for_new_users', 10, 2);


//Redirection for existing users
function oa_social_login_filter_redirect_for_existing_users ($url, $user_data)
{
	//Force the url to something else
	$url = 'http://my-website.com/welcome-back/';
	
	//Returning users will be redirected here
	return $url;
}
add_filter('oa_social_login_filter_login_redirect_url', 'oa_social_login_filter_redirect_for_existing_users', 10, 2);