diff --git a/src/components/CodeEditor.jsx b/src/components/CodeEditor.jsx
index abdce7d..770a1c8 100644
--- a/src/components/CodeEditor.jsx
+++ b/src/components/CodeEditor.jsx
@@ -13,7 +13,7 @@ import { showMinimap } from '@replit/codemirror-minimap';
 import { X, Save, Download, Maximize2, Minimize2, Eye, EyeOff } from 'lucide-react';
 import { api } from '../utils/api';
 
-function CodeEditor({ file, onClose, projectPath }) {
+function CodeEditor({ file, onClose, projectPath, isSidebar = false }) {
   const [content, setContent] = useState('');
   const [loading, setLoading] = useState(true);
   const [saving, setSaving] = useState(false);
@@ -321,14 +321,23 @@ function CodeEditor({ file, onClose, projectPath }) {
             }
           `}
         </style>
-        <div className="fixed inset-0 z-50 md:bg-black/50 md:flex md:items-center md:justify-center">
-          <div className="code-editor-loading w-full h-full md:rounded-lg md:w-auto md:h-auto p-8 flex items-center justify-center">
+        {isSidebar ? (
+          <div className="w-full h-full flex items-center justify-center bg-white dark:bg-gray-900">
             <div className="flex items-center gap-3">
               <div className="animate-spin rounded-full h-6 w-6 border-b-2 border-blue-600"></div>
               <span className="text-gray-900 dark:text-white">Loading {file.name}...</span>
             </div>
           </div>
-        </div>
+        ) : (
+          <div className="fixed inset-0 z-50 md:bg-black/50 md:flex md:items-center md:justify-center">
+            <div className="code-editor-loading w-full h-full md:rounded-lg md:w-auto md:h-auto p-8 flex items-center justify-center">
+              <div className="flex items-center gap-3">
+                <div className="animate-spin rounded-full h-6 w-6 border-b-2 border-blue-600"></div>
+                <span className="text-gray-900 dark:text-white">Loading {file.name}...</span>
+              </div>
+            </div>
+          </div>
+        )}
       </>
     );
   }
@@ -403,33 +412,32 @@ function CodeEditor({ file, onClose, projectPath }) {
           }
         `}
       </style>
-      <div className={`fixed inset-0 z-50 ${
+      <div className={isSidebar ?
+        'w-full h-full flex flex-col' :
+        `fixed inset-0 z-50 ${
           // Mobile: native fullscreen, Desktop: modal with backdrop
           'md:bg-black/50 md:flex md:items-center md:justify-center md:p-4'
         } ${isFullscreen ? 'md:p-0' : ''}`}>
-        <div className={`bg-white shadow-2xl flex flex-col ${
-        // Mobile: always fullscreen, Desktop: modal sizing
-        'w-full h-full md:rounded-lg md:shadow-2xl' +
-        (isFullscreen ? ' md:w-full md:h-full md:rounded-none' : ' md:w-full md:max-w-6xl md:h-[80vh] md:max-h-[80vh]')
-      }`}>
+        <div className={isSidebar ?
+          'bg-white dark:bg-gray-900 flex flex-col w-full h-full' :
+          `bg-white shadow-2xl flex flex-col ${
+          // Mobile: always fullscreen, Desktop: modal sizing
+          'w-full h-full md:rounded-lg md:shadow-2xl' +
+          (isFullscreen ? ' md:w-full md:h-full md:rounded-none' : ' md:w-full md:max-w-6xl md:h-[80vh] md:max-h-[80vh]')
+        }`}>
         {/* Header */}
-        <div className="flex items-center justify-between p-4 border-b border-gray-200 flex-shrink-0 min-w-0">
+        <div className="flex items-center justify-between p-4 border-b border-gray-200 dark:border-gray-700 flex-shrink-0 min-w-0">
           <div className="flex items-center gap-3 min-w-0 flex-1">
-            <div className="w-8 h-8 bg-blue-600 rounded flex items-center justify-center flex-shrink-0">
-              <span className="text-white text-sm font-mono">
-                {file.name.split('.').pop()?.toUpperCase() || 'FILE'}
-              </span>
-            </div>
             <div className="min-w-0 flex-1">
               <div className="flex items-center gap-2 min-w-0">
-                <h3 className="font-medium text-gray-900 truncate">{file.name}</h3>
+                <h3 className="font-medium text-gray-900 dark:text-white truncate">{file.name}</h3>
                 {file.diffInfo && (
-                  <span className="text-xs bg-blue-100 text-blue-600 px-2 py-1 rounded whitespace-nowrap">
+                  <span className="text-xs bg-blue-100 dark:bg-blue-900 text-blue-600 dark:text-blue-300 px-2 py-1 rounded whitespace-nowrap">
                     📝 Has changes
                   </span>
                 )}
               </div>
-              <p className="text-sm text-gray-500 truncate">{file.path}</p>
+              <p className="text-sm text-gray-500 dark:text-gray-400 truncate">{file.path}</p>
             </div>
           </div>
 
@@ -496,13 +504,15 @@ function CodeEditor({ file, onClose, projectPath }) {
               )}
             </button>
 
-            <button
-              onClick={toggleFullscreen}
-              className="hidden md:flex p-2 text-gray-600 dark:text-gray-400 hover:text-gray-900 dark:hover:text-white rounded-md hover:bg-gray-100 dark:hover:bg-gray-800 items-center justify-center"
-              title={isFullscreen ? 'Exit fullscreen' : 'Fullscreen'}
-            >
-              {isFullscreen ? <Minimize2 className="w-4 h-4" /> : <Maximize2 className="w-4 h-4" />}
-            </button>
+            {!isSidebar && (
+              <button
+                onClick={toggleFullscreen}
+                className="hidden md:flex p-2 text-gray-600 dark:text-gray-400 hover:text-gray-900 dark:hover:text-white rounded-md hover:bg-gray-100 dark:hover:bg-gray-800 items-center justify-center"
+                title={isFullscreen ? 'Exit fullscreen' : 'Fullscreen'}
+              >
+                {isFullscreen ? <Minimize2 className="w-4 h-4" /> : <Maximize2 className="w-4 h-4" />}
+              </button>
+            )}
 
             <button
               onClick={onClose}
@@ -565,7 +575,6 @@ function CodeEditor({ file, onClose, projectPath }) {
           <div className="flex items-center gap-4 text-sm text-gray-600 dark:text-gray-400">
             <span>Lines: {content.split('\n').length}</span>
             <span>Characters: {content.length}</span>
-            <span>Language: {file.name.split('.').pop()?.toUpperCase() || 'Text'}</span>
           </div>
 
           <div className="text-sm text-gray-500 dark:text-gray-400">
diff --git a/src/components/MainContent.jsx b/src/components/MainContent.jsx
index a9b1b81..dc84661 100644
--- a/src/components/MainContent.jsx
+++ b/src/components/MainContent.jsx
@@ -11,7 +11,7 @@
  * No session protection logic is implemented here - it's purely a props bridge.
  */
 
-import React, { useState, useEffect } from 'react';
+import React, { useState, useEffect, useRef } from 'react';
 import ChatInterface from './ChatInterface';
 import FileTree from './FileTree';
 import CodeEditor from './CodeEditor';
@@ -28,13 +28,13 @@ import { useTaskMaster } from '../contexts/TaskMasterContext';
 import { useTasksSettings } from '../contexts/TasksSettingsContext';
 import { api } from '../utils/api';
 
-function MainContent({ 
-  selectedProject, 
-  selectedSession, 
-  activeTab, 
-  setActiveTab, 
-  ws, 
-  sendMessage, 
+function MainContent({
+  selectedProject,
+  selectedSession,
+  activeTab,
+  setActiveTab,
+  ws,
+  sendMessage,
   messages,
   isMobile,
   isPWA,
@@ -61,6 +61,9 @@ function MainContent({
   const [editingFile, setEditingFile] = useState(null);
   const [selectedTask, setSelectedTask] = useState(null);
   const [showTaskDetail, setShowTaskDetail] = useState(false);
+  const [editorWidth, setEditorWidth] = useState(600);
+  const [isResizing, setIsResizing] = useState(false);
+  const resizeRef = useRef(null);
   
   // PRD Editor state
   const [showPRDEditor, setShowPRDEditor] = useState(false);
@@ -153,6 +156,52 @@ function MainContent({
     console.log('Update task status:', taskId, newStatus);
     refreshTasks?.();
   };
+
+  // Handle resize functionality
+  const handleMouseDown = (e) => {
+    if (isMobile) return; // Disable resize on mobile
+    setIsResizing(true);
+    e.preventDefault();
+  };
+
+  useEffect(() => {
+    const handleMouseMove = (e) => {
+      if (!isResizing) return;
+
+      const container = resizeRef.current?.parentElement;
+      if (!container) return;
+
+      const containerRect = container.getBoundingClientRect();
+      const newWidth = containerRect.right - e.clientX;
+
+      // Min width: 300px, Max width: 80% of container
+      const minWidth = 300;
+      const maxWidth = containerRect.width * 0.8;
+
+      if (newWidth >= minWidth && newWidth <= maxWidth) {
+        setEditorWidth(newWidth);
+      }
+    };
+
+    const handleMouseUp = () => {
+      setIsResizing(false);
+    };
+
+    if (isResizing) {
+      document.addEventListener('mousemove', handleMouseMove);
+      document.addEventListener('mouseup', handleMouseUp);
+      document.body.style.cursor = 'col-resize';
+      document.body.style.userSelect = 'none';
+    }
+
+    return () => {
+      document.removeEventListener('mousemove', handleMouseMove);
+      document.removeEventListener('mouseup', handleMouseUp);
+      document.body.style.cursor = '';
+      document.body.style.userSelect = '';
+    };
+  }, [isResizing]);
+
   if (isLoading) {
     return (
       <div className="h-full flex flex-col">
@@ -234,10 +283,10 @@ function MainContent({
   return (
     <div className="h-full flex flex-col">
       {/* Header with tabs */}
-      <div 
+      <div
         className="bg-white dark:bg-gray-800 border-b border-gray-200 dark:border-gray-700 p-3 sm:p-4 pwa-header-safe flex-shrink-0"
       >
-        <div className="flex items-center justify-between">
+        <div className="flex items-center justify-between relative">
           <div className="flex items-center space-x-2 sm:space-x-3">
             {isMobile && (
               <button
@@ -409,11 +458,13 @@ function MainContent({
         </div>
       </div>
 
-      {/* Content Area */}
-      <div className="flex-1 flex flex-col min-h-0 overflow-hidden">
-        <div className={`h-full ${activeTab === 'chat' ? 'block' : 'hidden'}`}>
-          <ErrorBoundary showDetails={true}>
-            <ChatInterface
+      {/* Content Area with Right Sidebar */}
+      <div className="flex-1 flex min-h-0 overflow-hidden">
+        {/* Main Content */}
+        <div className={`flex-1 flex flex-col min-h-0 overflow-hidden ${editingFile ? 'mr-0' : ''}`}>
+          <div className={`h-full ${activeTab === 'chat' ? 'block' : 'hidden'}`}>
+            <ErrorBoundary showDetails={true}>
+              <ChatInterface
               selectedProject={selectedProject}
               selectedSession={selectedSession}
               ws={ws}
@@ -513,14 +564,45 @@ function MainContent({
             onClearLogs={() => setServerLogs([])}
           /> */}
         </div>
+        </div>
+
+        {/* Code Editor Right Sidebar - Desktop only, Mobile uses modal */}
+        {editingFile && !isMobile && (
+          <>
+            {/* Resize Handle */}
+            <div
+              ref={resizeRef}
+              onMouseDown={handleMouseDown}
+              className="flex-shrink-0 w-1 bg-gray-200 dark:bg-gray-700 hover:bg-blue-500 dark:hover:bg-blue-600 cursor-col-resize transition-colors relative group"
+              title="Drag to resize"
+            >
+              {/* Visual indicator on hover */}
+              <div className="absolute inset-y-0 left-1/2 -translate-x-1/2 w-1 bg-blue-500 dark:bg-blue-600 opacity-0 group-hover:opacity-100 transition-opacity" />
+            </div>
+
+            {/* Editor Sidebar */}
+            <div
+              className="flex-shrink-0 border-l border-gray-200 dark:border-gray-700 h-full overflow-hidden"
+              style={{ width: `${editorWidth}px` }}
+            >
+              <CodeEditor
+                file={editingFile}
+                onClose={handleCloseEditor}
+                projectPath={selectedProject?.path}
+                isSidebar={true}
+              />
+            </div>
+          </>
+        )}
       </div>
 
-      {/* Code Editor Modal */}
-      {editingFile && (
+      {/* Code Editor Modal for Mobile */}
+      {editingFile && isMobile && (
         <CodeEditor
           file={editingFile}
           onClose={handleCloseEditor}
           projectPath={selectedProject?.path}
+          isSidebar={false}
         />
       )}