fix(home): restore homepage event banner styling

The .event-banner rules were dropped during an _event.css rewrite, so the
homepage promo banner rendered unstyled (full-width dark text, no gradient).
Restored the banner styles and removed the em-dash from the banner copy.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

en/index.html

@@ -213,7 +213,7 @@
             <div class="event-banner-inner">
                 <div class="event-banner-copy">
                     <span class="event-banner-tag"><i class="fas fa-bullhorn" aria-hidden="true"></i> Upcoming event</span>
-                    <p class="event-banner-text"><strong>Meet Student Slovenia 2026</strong> &middot; Friday, 4 September, NLB Banka, Skopje &amp; live stream &mdash; for future students and their parents.</p>
+                    <p class="event-banner-text"><strong>Meet Student Slovenia 2026</strong> &middot; Friday, 4 September, NLB Banka, Skopje &amp; live stream, for future students and their parents.</p>
                 </div>
                 <a class="btn btn-primary-orange event-banner-cta" href="../en/news/meet-student-slovenia-2026/">Learn more &amp; register</a>
             </div>