Refactor code structure for improved readability and maintainability

Website/templates/base.html

@@ -143,22 +143,12 @@
         .brand {
             display: inline-flex;
             align-items: center;
-            gap: 0.72rem;
-            font-family: "Merriweather", Georgia, serif;
-            font-size: 1.22rem;
-            font-weight: 700;
-            letter-spacing: 0.03em;
-            color: var(--brand-strong);
         }
 
         .brand img {
-            width: 48px;
             height: 48px;
-            border-radius: 12px;
-            object-fit: cover;
-            border: 1px solid #bccdc4;
-            box-shadow: 0 8px 16px rgba(19, 49, 54, 0.14);
-            background: #ffffff;
+            width: auto;
+            object-fit: contain;
         }
 
         .nav-links {
@@ -511,8 +501,7 @@
     <nav class="site-nav" role="navigation" aria-label="Hauptnavigation">
         <div class="site-shell site-nav-inner">
             <a class="brand" href="{{ url_for('default') }}">
-                <img src="{{ url_for('static', filename='images/Logo-clear.png') }}" alt="Invario Logo">
-                <span>Invario</span>
+                <img src="{{ url_for('static', filename='logos/Logo ohne Background .png') }}" alt="Invario Logo">
             </a>
             <button type="button" class="nav-toggle" id="mobileMenuToggle" aria-expanded="false" aria-controls="mainNav" aria-label="Navigation öffnen">
                 <svg viewBox="0 0 24 24" aria-hidden="true" focusable="false">