vision refactor

app/vision/page.tsx

@@ -747,23 +747,16 @@ export default function VisionPage() {
   if (selectedConference && jitsiUrl) {
     return (
       <main className="w-full h-[calc(100vh-3rem)] bg-black flex flex-col mt-12">
-        {/* Header with back button */}
-        <div className="bg-white border-b border-gray-200 px-4 py-3 flex items-center gap-4 shrink-0">
-          <Button
-            variant="ghost"
-            size="sm"
-            onClick={handleBack}
-            className="flex items-center gap-2"
-          >
-            <ArrowLeft className="h-4 w-4" />
-            Retour
-          </Button>
-          <div className="flex-1">
-            <h1 className="text-sm font-medium text-gray-900">
-              {selectedConference.type === "group" ? "Groupe" : "Mission"}: {selectedConference.name}
-            </h1>
-          </div>
-        </div>
+        {/* Floating back button */}
+        <Button
+          variant="ghost"
+          size="sm"
+          onClick={handleBack}
+          className="absolute top-16 left-4 z-10 bg-white/90 hover:bg-white text-gray-900 shadow-lg"
+        >
+          <ArrowLeft className="h-4 w-4 mr-2" />
+          Retour
+        </Button>
         
         {/* Jitsi iframe */}
         <div className="flex-1 overflow-hidden">