Made the header button show/hide work

app/styles/container.css

@@ -0,0 +1,34 @@
+/* container.css */
+.container {
+    display: flex;
+    height: 100vh;
+    width: 100vw;
+    overflow: hidden;
+    position: relative; /* Ensure relative positioning for proper transitions */
+}
+
+.left-panel {
+    width: 30vw; /* Adjust as needed */
+    transition: width 0.3s ease, visibility 0.3s ease; /* Transition for width, opacity, and visibility */
+}
+
+.left-panel.hidden {
+    opacity: 0; /* Fade out when hidden */
+    width: 0; /* Set width to 0 when hidden */
+    visibility: hidden; /* Hide the panel while keeping the space occupied */
+    margin-right: -30vw;
+}
+
+.conversation-container {
+    flex: 1;
+    transition: width 0.3s ease, visibility 0.3s ease; /* Transition for margin-left */
+}
+
+/* Adjust margin-left when panel is shown or hidden */
+.conversation-container.expanded {
+    margin-left: 0;
+}
+
+.conversation-container.collapsed {
+    margin-left: 30vw; /* Same as the width of the left-panel */
+}