diff --git a/frontend/src/App.tsx b/frontend/src/App.tsx
index b847623..bbcf83c 100644
--- a/frontend/src/App.tsx
+++ b/frontend/src/App.tsx
@@ -1,4 +1,4 @@
-import { useEffect, useState, useCallback } from 'react';
+import { useEffect, useState, useCallback, useRef } from 'react';
 import type { Site } from '@/types/index.ts';
 import type { Preset } from '@/services/api.ts';
 import { api } from '@/services/api.ts';
@@ -117,6 +117,46 @@ export default function App() {
   const [showShortcuts, setShowShortcuts] = useState(false);
   const [kbDeleteTarget, setKbDeleteTarget] = useState<{ id: string; name: string } | null>(null);
 
+  // Resizable sidebar
+  const PANEL_MIN = 300;
+  const PANEL_MAX = 600;
+  const PANEL_DEFAULT = 380;
+  const [panelWidth, setPanelWidth] = useState(() => {
+    const saved = localStorage.getItem('rfcp-panel-width');
+    const n = saved ? Number(saved) : PANEL_DEFAULT;
+    return n >= PANEL_MIN && n <= PANEL_MAX ? n : PANEL_DEFAULT;
+  });
+  const isDragging = useRef(false);
+
+  const handleDragStart = useCallback((e: React.MouseEvent) => {
+    e.preventDefault();
+    isDragging.current = true;
+    document.body.style.cursor = 'col-resize';
+    document.body.style.userSelect = 'none';
+
+    const onMove = (ev: MouseEvent) => {
+      if (!isDragging.current) return;
+      const newWidth = window.innerWidth - ev.clientX;
+      const clamped = Math.max(PANEL_MIN, Math.min(PANEL_MAX, newWidth));
+      setPanelWidth(clamped);
+    };
+
+    const onUp = () => {
+      isDragging.current = false;
+      document.body.style.cursor = '';
+      document.body.style.userSelect = '';
+      document.removeEventListener('mousemove', onMove);
+      document.removeEventListener('mouseup', onUp);
+      setPanelWidth((w) => {
+        localStorage.setItem('rfcp-panel-width', String(w));
+        return w;
+      });
+    };
+
+    document.addEventListener('mousemove', onMove);
+    document.addEventListener('mouseup', onUp);
+  }, []);
+
   // Load sites from IndexedDB on mount
   useEffect(() => {
     loadSites();
@@ -587,9 +627,16 @@ export default function App() {
         <div
           className={`${
             panelCollapsed ? 'hidden' : 'flex'
-          } flex-col w-full sm:w-80 lg:w-96 bg-gray-50 dark:bg-dark-bg border-l border-gray-200 dark:border-dark-border
+          } flex-col bg-gray-50 dark:bg-dark-bg border-l border-gray-200 dark:border-dark-border
             overflow-y-auto absolute sm:relative inset-0 sm:inset-auto z-[1001]`}
+          style={{ width: window.innerWidth >= 640 ? panelWidth : undefined }}
         >
+          {/* Resize drag handle (desktop only) */}
+          <div
+            onMouseDown={handleDragStart}
+            className="hidden sm:block absolute left-0 top-0 bottom-0 w-1 cursor-col-resize z-10
+              hover:bg-blue-400/50 active:bg-blue-500/60 transition-colors"
+          />
           {/* Mobile drag handle + close */}
           <div className="sm:hidden flex flex-col items-center pt-2 pb-1">
             <div className="w-12 h-1 bg-gray-300 dark:bg-dark-border rounded-full mb-2" />