fix(css): kebab-case keyframe name and empty line before rule

fix(php): duplicate id 'form-result' → 'form-errors' for error container

css/haus-schleusingen.css

@@ -1216,7 +1216,7 @@ footer {
     gap: 0;
     z-index: 95;
     border-bottom: 1px solid var(--warm);
-    animation: slideDown 0.3s ease;
+    animation: slide-down 0.3s ease;
   }
 
   nav.mobile-open .nav-links a {
@@ -1239,11 +1239,12 @@ footer {
     background: transparent;
   }
 
-  @keyframes slideDown {
+  @keyframes slide-down {
     from {
       opacity: 0;
       transform: translateY(-10px);
     }
+
     to {
       opacity: 1;
       transform: translateY(0);