diff --git a/web/src/App.tsx b/web/src/App.tsx
index 2c93b40..8c2650b 100644
--- a/web/src/App.tsx
+++ b/web/src/App.tsx
@@ -1,5 +1,5 @@
 import { useEffect, useMemo, useRef, useState } from "preact/hooks";
-import { Check, ChevronDown, Globe2, LogOut, MessageSquare, Plus, Search, SendHorizontal, Trash2 } from "lucide-preact";
+import { Check, ChevronDown, Globe2, Menu, MessageSquare, Plus, Search, SendHorizontal, Trash2 } from "lucide-preact";
 import { Button } from "@/components/ui/button";
 import { Textarea } from "@/components/ui/textarea";
 import { Separator } from "@/components/ui/separator";
@@ -301,6 +301,7 @@ export default function App() {
   const searchRunAbortRef = useRef<AbortController | null>(null);
   const searchRunCounterRef = useRef(0);
   const [contextMenu, setContextMenu] = useState<ContextMenuState | null>(null);
+  const [isMobileSidebarOpen, setIsMobileSidebarOpen] = useState(false);
 
   useEffect(() => {
     if (typeof document === "undefined") return;
@@ -549,6 +550,7 @@ export default function App() {
     setSelectedItem(null);
     setSelectedChat(null);
     setSelectedSearch(null);
+    setIsMobileSidebarOpen(false);
   };
 
   const handleCreateSearch = () => {
@@ -558,6 +560,7 @@ export default function App() {
     setSelectedItem(null);
     setSelectedChat(null);
     setSelectedSearch(null);
+    setIsMobileSidebarOpen(false);
   };
 
   const openContextMenu = (event: MouseEvent, item: SidebarSelection) => {
@@ -956,7 +959,21 @@ export default function App() {
   return (
     <div className="h-full">
       <div className="flex h-full w-full overflow-hidden bg-background">
-        <aside className="flex w-80 shrink-0 flex-col border-r bg-[hsl(272_34%_14%)]">
+        {isMobileSidebarOpen ? (
+          <button
+            type="button"
+            className="fixed inset-0 z-30 bg-black/45 md:hidden"
+            onClick={() => setIsMobileSidebarOpen(false)}
+            aria-label="Close sidebar"
+          />
+        ) : null}
+
+        <aside
+          className={cn(
+            "fixed inset-y-0 left-0 z-40 flex w-[85vw] max-w-80 shrink-0 flex-col border-r bg-[hsl(272_34%_14%)] transition-transform md:static md:z-auto md:w-80 md:max-w-none",
+            isMobileSidebarOpen ? "translate-x-0" : "-translate-x-full md:translate-x-0"
+          )}
+        >
           <div className="grid grid-cols-2 gap-2 p-3">
             <Button className="justify-start gap-2" onClick={handleCreateChat}>
               <Plus className="h-4 w-4" />
@@ -992,6 +1009,7 @@ export default function App() {
                     setContextMenu(null);
                     setDraftKind(null);
                     setSelectedItem({ kind: item.kind, id: item.id });
+                    setIsMobileSidebarOpen(false);
                   }}
                   onContextMenu={(event) => openContextMenu(event, { kind: item.kind, id: item.id })}
                   type="button"
@@ -1014,12 +1032,25 @@ export default function App() {
 
         <main className="flex min-w-0 flex-1 flex-col">
           <header className="flex flex-wrap items-center justify-between gap-3 border-b px-4 py-3">
-            <div>
+            <div className="flex items-start gap-2">
+              <Button
+                type="button"
+                size="icon"
+                variant="ghost"
+                className="-ml-1 h-8 w-8 md:hidden"
+                onClick={() => setIsMobileSidebarOpen(true)}
+                aria-label="Open sidebar"
+              >
+                <Menu className="h-4 w-4" />
+              </Button>
+
+              <div>
               <h1 className="text-sm font-semibold md:text-base">{selectedTitle}</h1>
               <p className="text-xs text-muted-foreground">
                 Sybil Web{authMode ? ` (${authMode === "open" ? "open mode" : "token mode"})` : ""}
                 {isSearchMode ? " • Exa Search" : ""}
               </p>
+              </div>
             </div>
             <div className="flex w-full max-w-xl items-center gap-2 md:w-auto">
               {!isSearchMode ? (