Refactor social login button styles and update text for Facebook login

- Updated CSS for social login buttons to improve layout and hover effects.
- Changed the text for the Facebook login button from "Sign in with Facebook" to "Zaloguj się za pomocą Facebook" for localization.
- Adjusted JavaScript to reflect the new button text.

modules/thecheckout/views/templates/front/blocks/login-form.tpl

@@ -43,7 +43,7 @@
         {/if}
         {if $z_tc_config->social_login_fb && $z_tc_config->social_login_fb_app_id && $z_tc_config->social_login_fb_app_secret}
           {*<div class="fb-login-button" data-max-rows="1" data-onlogin="fb_checkLoginState();" data-size="medium" data-button-type="login_with" data-show-faces="false" data-auto-logout-link="false" data-use-continue-as="false"></div>*}
-          <div id="tc-facebook-signin" class="tc-social-login-btn"><span class="social-logo"><span class="facebook-logo"></span></span>{l s='Sign in with Facebook' mod='thecheckout'}</div>
+          <div id="tc-facebook-signin" class="tc-social-login-btn"><span class="social-logo"><span class="facebook-logo"></span></span>{l s='Zaloguj się za pomocą Facebook' mod='thecheckout'}</div>
         {/if}
         {if $z_tc_config->social_login_google && $z_tc_config->social_login_google_client_id && $z_tc_config->social_login_google_client_secret}
           {*Google+ login <div class="g-signin2" data-onsuccess="tc_onSignIn"></div>*}