Possible fix for actual dynamic tabs?

dynamic_native_tabs.css

@@ -1,27 +1,30 @@
-#main-window .toolbar-items {
+/* Transição suave para o TabsToolbar */
+#main-window #TabsToolbar {
     overflow: hidden;
-    transition: height 0.3s 0.3s !important;
+    max-height: 3em; /* Estado expandido */
+    transition: max-height 0.3s ease-in-out !important;
 }
 
-/* Default state: Set initial height to enable animation */
-#main-window .toolbar-items {
-    height: 3em !important;
+/* Toolbar items */
+#main-window #TabsToolbar .toolbar-items {
+    overflow: hidden;
+    max-height: 40px; /* Estado expandido */
+    transition: max-height 0.3s ease-in-out !important;
 }
 
-#main-window[uidensity="touch"] .toolbar-items {
-    height: 3.35em !important;
+/* Estado oculto: TabsToolbar colapsado */
+#main-window[titlepreface*="​"] #TabsToolbar {
+    max-height: 0; /* Estado colapsado */
+    visibility: hidden; /* Evita conteúdo interativo enquanto colapsado */
+    transition: max-height 0.3s ease-in-out, visibility 0s 0.3s !important; /* atraso para ocultar */
 }
 
-#main-window[uidensity="compact"] .toolbar-items {
-    height: 2.7em !important;
+/* Estado oculto para os itens da toolbar */
+#main-window[titlepreface*="​"] #TabsToolbar .toolbar-items {
+    max-height: 0;
 }
 
-/* Hidden state: Hide native tabs strip */
-#main-window[titlepreface*="​"] .toolbar-items {
-    height: 0 !important;
-}
-
-/* Hidden state: Fix z-index of active pinned tabs */
+/* Corrige o z-index de abas fixadas */
 #main-window[titlepreface*="​"] #tabbrowser-tabs {
     z-index: 0 !important;
 }

userChrome.css

@@ -1,2 +1,2 @@
 @import url(smaller_sidebar_header.css);
-@import url(autohide_tabstoolbar_v2.css);
+@import url(dynamic_native_tabs.css);