feat(ui): improve sidebar logo visibility

Author: ReturnFI

core/scripts/webpanel/assets/img/favicon-bg.ico

@@ -53,7 +53,7 @@
             <!-- Brand Logo -->
             <a href="{{ url_for('index') }}" class="brand-link">
                 <img src="{{ url_for('assets', path='img/logo.png') }}" alt="Blitz Logo"
-                    class="brand-image img-circle elevation-3" style="opacity: .8">
+                    class="brand-image img-circle elevation-3" style="background-color: #f8f9fa; padding: 3px;">
                 <span class="brand-text font-weight-light">Blitz Dashboard</span>
             </a>