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diff --git a/SUB_EDITOR.md b/SUB_EDITOR.md
new file mode 100644
index 0000000..ed03259
--- /dev/null
+++ b/SUB_EDITOR.md
@@ -0,0 +1,182 @@
+Dưới đây là toàn bộ nội dung tài liệu đặc tả kỹ thuật đã được chuyển đổi sang định dạng Markdown chuẩn, tối ưu hóa các khối mã nguồn (`python`, `text`), căn chỉnh bảng biểu, sơ đồ luồng ASCII và các công thức toán học dạng LaTeX:
+
+# Technical Specification: Sub-Tab Audio Clip Editor & DSP Operations
+
+This document outlines the software engineering specification for the temporary isolated Sub-Tab Audio Clip Editor. It defines internal clipboard mechanics, DSP algorithms for selection-based operations, Context Menu structures, and main application menu shortcuts.
+
+---
+
+## 1. Clipboard & Cursor-Aligned Insertion Mechanics
+
+The Sub-Tab workspace features an isolated, low-latency stereo/mono audio buffer. The editor tracks a local virtual playhead position $t_{\text{cursor}}$ and handles clipboard buffers using non-destructive splicing techniques.
+
+```text
+                  Local Timeline Buffer
++-------------------------------------------------------+
+|  Track Waveform Segment       │                       |
++-------------------------------┼-----------------------+
+                                ▲
+                          t_cursor (Insertion Point)
+                                │
+                                ▼ [ PASTE TRIGGERED ]
++-------------------------------------------------------+
+|  Track Waveform Segment       │ CLIPBOARD DATA │      |
++-------------------------------------------------------+
+                                 ◄──────────────►
+                                   clip_duration
+
+```
+
+### 1.1. Cursor Paste Action
+
+When a paste command is issued (either via Context Menu, Application Menu, or Hotkey):
+
+* **Payload Extraction:** Retrieve the copied `AudioBufferSegment` from the system/application clipboard.
+* **Splicing Boundary Calculations:** Slice the current active timeline buffer at $t_{\text{cursor}}$.
+* **Re-allocation & Stitching:**
+* Compute the new duration: $T_{\text{new}} = T_{\text{original}} + T_{\text{clipboard}}$.
+* Allocate a new virtual audio array $Y_{\text{new}}$:
+
+
+
+$$Y_{\text{new}}(t) = \begin{cases} Y_{\text{original}}(t) & 0 \le t < t_{\text{cursor}} \\ Y_{\text{clipboard}}(t - t_{\text{cursor}}) & t_{\text{cursor}} \le t < t_{\text{cursor}} + T_{\text{clipboard}} \\ Y_{\text{original}}(t - T_{\text{clipboard}}) & t_{\text{cursor}} + T_{\text{clipboard}} \le t \le T_{\text{new}} \end{cases}$$
+
+* **Playhead Update:** Advance the active playhead $t_{\text{cursor}}$ immediately to $t_{\text{cursor}} + T_{\text{clipboard}}$.
+
+---
+
+## 2. Selection Context Menu & DSP Engine
+
+Right-clicking inside a highlighted region $[T_{\text{start}}, T_{\text{end}}]$ of the Waveform Canvas triggers an overlay context menu containing the following DSP and editing commands.
+
+```text
++---------------------------------------------+
+| Selection: [ 01:02.100 - 01:05.400 ]        |
++---------------------------------------------+
+|  Normalize Selection To Peak                |
+|  Adjust Gain/Volume...                      |
+|  Adjust Panning (Stereo Balance)...         |
+|  Fade In (Linear/Exponential)               |
+|  Fade Out (Linear/Exponential)              |
+|---------------------------------------------|
+|  Cut                                 Ctrl+X |
+|  Copy                                Ctrl+C |
+|  Paste                               Ctrl+V |
+|  Delete Selected Segment                Del |
+|---------------------------------------------|
+|  Loop Selection: [ ▲ ] [ 4 ] [ ▼ ] times    |
++---------------------------------------------+
+
+```
+
+### 2.1. Normalize Selection
+
+Scales the peak amplitude of the selected segment to a target ceiling $A_{\text{target}}$ (defaulting to $1.0$ or $0\text{ dBFS}$):
+
+$$Y_{\text{norm}}(t) = Y(t) \cdot \frac{A_{\text{target}}}{\max_{u \in [T_{\text{start}}, T_{\text{end}}]} \vert{}Y(u)\vert{}} \quad \text{for } t \in [T_{\text{start}}, T_{\text{end}}]$$
+
+### 2.2. Volume (Gain dB) Adjustment
+
+Applies a static linear gain multiplier derived from user-specified decibel scaling values ($\Delta\text{dB}$):
+
+$$G = 10^{\frac{\Delta\text{dB}}{20}}$$
+
+$$Y_{\text{gained}}(t) = Y(t) \cdot G \quad \text{for } t \in [T_{\text{start}}, T_{\text{end}}]$$
+
+### 2.3. Panning (Stereo Balance)
+
+Applies a constant-power panning law across Left ($L$) and Right ($R$) channels based on the panning angle $\theta \in [0, \pi/2]$, where $\theta = \pi/4$ represents absolute center:
+
+$$Y_L(t) = Y_{\text{mono}}(t) \cdot \cos(\theta), \quad Y_R(t) = Y_{\text{mono}}(t) \cdot \sin(\theta)$$
+
+### 2.4. Fade-In and Fade-Out (Linear / Exponential)
+
+* **Linear Fade-In Curve:**
+
+$$f_{\text{in}}(t) = \frac{t - T_{\text{start}}}{T_{\text{end}} - T_{\text{start}}} \quad \text{for } t \in [T_{\text{start}}, T_{\text{end}}]$$
+
+* **Linear Fade-Out Curve:**
+
+$$f_{\text{out}}(t) = 1.0 - \frac{t - T_{\text{start}}}{T_{\text{end}} - T_{\text{start}}} \quad \text{for } t \in [T_{\text{start}}, T_{\text{end}}]$$
+
+### 2.5. Delete, Cut, and Copy
+
+* **Delete:** Erases the selected segment $[T_{\text{start}}, T_{\text{end}}]$ and shifts all subsequent samples leftward.
+* **Cut:** Copies the selected samples to the clipboard, then executes the *Delete* routine.
+* **Copy:** Writes the targeted buffer segment to the clip memory without modifying the timeline.
+
+### 2.6. Segment Looping with Step Multiplier
+
+Repeats the selected segment $[T_{\text{start}}, T_{\text{end}}]$ consecutively $N$ times. The menu provides a numeric spinner (Up/Down buttons) to adjust $N$:
+
+1. Extract segment: $Y_{\text{segment}} = Y(t)$ for $t \in [T_{\text{start}}, T_{\text{end}}]$.
+2. Compute new duration adjustment: $\Delta L = (N - 1) \cdot (T_{\text{end}} - T_{\text{start}})$.
+3. Duplicate and insert $Y_{\text{segment}}$ array $N-1$ times directly after $T_{\text{end}}$.
+
+---
+
+## 3. Global Menu Bar & Keyboard Shortcut Matrix
+
+All context-dependent sub-tab actions are mapped directly to the global Menu Bar at the top of the DAW window, as specified in `image_e0e462.png`.
+
+```text
+File  Edit  View  Insert  Track  Options  Actions  Extensions  Help
+       │
+       ├── Normalize Selection  [Ctrl+Alt+N]
+       ├── Adjust Volume...     [V]
+       ├── Adjust Panning...    [P]
+       ├── Fade In              [F]
+       ├── Fade Out             [G]
+       ├── Cut                  [Ctrl+X]
+       ├── Copy                 [Ctrl+C]
+       ├── Paste                [Ctrl+V]
+       ├── Delete               [Del]
+       └── Loop Clip...         [Ctrl+L]
+
+```
+
+### 3.1. Keyboard Mapping Table
+
+To maximize speed and accessibility, the system listens for global key event hooks within the Sub-Tab window focus:
+
+| Action Command | Main Menu Category | Recommended Keyboard Shortcut | Python Event Trigger (`QKeyEvent`) |
+| --- | --- | --- | --- |
+| **Cut** | Edit -> Cut | `Ctrl + X` | `Qt.Key.Key_X` + `ControlModifier` |
+| **Copy** | Edit -> Copy | `Ctrl + C` | `Qt.Key.Key_C` + `ControlModifier` |
+| **Paste** | Edit -> Paste | `Ctrl + V` | `Qt.Key.Key_V` + `ControlModifier` |
+| **Delete** | Edit -> Delete | `Del` / `Backspace` | `Qt.Key.Key_Delete` / `Key_Backspace` |
+| **Normalize** | Actions -> Normalize | `Ctrl + Alt + N` | `Qt.Key.Key_N` + `ControlModifier` + `AltModifier` | 
+| **Fade In** | Actions -> Fade In | `F` | `Qt.Key.Key_F` |
+| **Fade Out** | Actions -> Fade Out | `G` | `Qt.Key.Key_G` |
+| **Loop Segment** | Actions -> Loop... | `Ctrl + L` | `Qt.Key.Key_L` + `ControlModifier` |
+| **Adjust Volume** | Actions -> Gain... | `V` | `Qt.Key.Key_V` |
+| **Adjust Panning** | Actions -> Panning... | `P` | `Qt.Key.Key_P` |
+
+---
+
+## 4. Python Implementation Notes for Docker Server Porting
+
+When porting these sub-tab operations to your Python DSP engine (`core/audio_editor.py`), use NumPy slice vectors to perform non-destructive edits on waveforms:
+
+```python
+# Prototype helper for non-destructive volume adjustment in Python
+import numpy as np
+
+def apply_gain_on_segment(y: np.ndarray, sr: int, start_sec: float, end_sec: float, gain_db: float) -> np.ndarray:
+    """
+    Applies gain in dB to a selected segment of a mono numpy audio array.
+    """
+    # 1. Translate time coordinates securely with boundary checking
+    start_sample = max(0, int(start_sec * sr))
+    end_sample = min(len(y), int(end_sec * sr))
+    
+    # 2. Convert dB value to linear multiplier
+    multiplier = 10.0 ** (gain_db / 20.0)
+    
+    # 3. Create a deep copy and modify segment in-place
+    y_edited = np.copy(y)
+    y_edited[start_sample:end_sample] *= multiplier
+    
+    return y_edited
+
+```
\ No newline at end of file
diff --git a/app/templates/index.html b/app/templates/index.html
index f741938..695f82c 100644
--- a/app/templates/index.html
+++ b/app/templates/index.html
@@ -6,9 +6,9 @@
     <title>SonicForge Studio - Professional DAW Editor</title>
     <script src="https://cdn.tailwindcss.com"></script>
     <script src="https://unpkg.com/lucide@latest"></script>
-    <script src="https://unpkg.com/react@18/umd/react.production.min.js"></script>
-    <script src="https://unpkg.com/react-dom@18/umd/react-dom.production.min.js"></script>
-    <script src="https://unpkg.com/@babel/standalone/babel.min.js"></script>
+    <script src="https://unpkg.com/react@18.3.1/umd/react.production.min.js"></script>
+    <script src="https://unpkg.com/react-dom@18.3.1/umd/react-dom.production.min.js"></script>
+    <script src="https://unpkg.com/@babel/standalone@7.26.0/babel.min.js"></script>
     <style>
         body { 
             background-color: #1a1a1a; 
@@ -460,70 +460,35 @@
             const isDraggingRulerRef = useRef(false);
             const handlePlayPauseRef = useRef(null);
 
-            // ── Keyboard Shortcuts (LOOP_EDITOR_2.md §4.3, menu shortcuts) ──
+            // ── Keyboard Shortcuts ──
             const handleUndoRef = useRef(handleUndo);
             const handleRedoRef = useRef(handleRedo);
-            const handlePlayPauseRef = useRef(null);
-            const keyHandlersRef = useRef({});
             handleUndoRef.current = handleUndo;
             handleRedoRef.current = handleRedo;
 
-            // Keep key handlers up-to-date via refs (avoids stale closures in useEffect)
             useEffect(() => {
-                keyHandlersRef.current = {
-                    addNewTrack, handleSplitTrack, handleMergeTracks, handleCopyTrack,
-                    handleCutTrack, handleDeleteTrack, contextMenuPaste, openTempTab,
-                    openTempTabImport: () => {
-                        const input = document.createElement('input');
-                        input.type = 'file'; input.accept = 'audio/*';
-                        input.onchange = async (e) => {
-                            if (e.target.files[0]) {
-                                addNewTrack();
-                                const newId = (tracks.length + 1).toString();
-                                setTimeout(() => loadFileOnTrack(newId, e.target.files[0]), 100);
-                            }
-                        };
-                        input.click();
-                    },
-                };
-            });
-
-            useEffect(() => {
-                const handleKeyDown = (e) => {
-                    const k = keyHandlersRef.current;
+                const handler = (e) => {
                     const ctrl = e.ctrlKey || e.metaKey;
                     const alt = e.altKey;
-
-                    // Space: play/pause
-                    if (e.key === ' ' || e.code === 'Space') {
-                        e.preventDefault();
-                        if (handlePlayPauseRef.current) handlePlayPauseRef.current();
-                        return;
-                    }
-
-                    // Ctrl+Z: Undo, Ctrl+Y or Ctrl+Shift+Z: Redo
+                    if (e.key === ' ' || e.code === 'Space') { e.preventDefault(); if (handlePlayPauseRef.current) handlePlayPauseRef.current(); return; }
                     if (ctrl && e.key === 'z' && !e.shiftKey) { e.preventDefault(); handleUndoRef.current(); return; }
                     if (ctrl && (e.key === 'y' || (e.key === 'z' && e.shiftKey))) { e.preventDefault(); handleRedoRef.current(); return; }
-
-                    // File menu shortcuts
                     if (ctrl && !alt && e.key === 'o') { e.preventDefault(); showToast('Open Project dialog','info'); return; }
                     if (ctrl && !alt && e.key === 's') { e.preventDefault(); showToast('Project saved','success'); return; }
                     if (ctrl && alt && e.key === 's') { e.preventDefault(); showToast('Save As dialog','info'); return; }
-
-                    // Edit menu shortcuts
-                    if (ctrl && !alt && e.key === 'i') { e.preventDefault(); k.addNewTrack(); return; }
-                    if (ctrl && alt && e.key === 'i') { e.preventDefault(); k.openTempTabImport(); return; }
-                    if (ctrl && !alt && e.key === 'e') { e.preventDefault(); k.openTempTab(); return; }
-                    if (!ctrl && !alt && (e.key === 's' || e.key === 'S')) { e.preventDefault(); k.handleSplitTrack(selectedTrackId); return; }
-                    if (ctrl && !alt && e.key === 'm') { e.preventDefault(); k.handleMergeTracks(); return; }
-                    if (ctrl && !alt && e.key === 'c') { e.preventDefault(); k.handleCopyTrack(); return; }
-                    if (ctrl && !alt && e.key === 'x') { e.preventDefault(); k.handleCutTrack(); return; }
-                    if (ctrl && !alt && e.key === 'v') { e.preventDefault(); k.contextMenuPaste(); return; }
-                    if (e.key === 'Delete' || e.key === 'Del') { e.preventDefault(); k.handleDeleteTrack(); return; }
+                    if (ctrl && !alt && e.key === 'i') { e.preventDefault(); addNewTrack(); return; }
+                    if (ctrl && alt && e.key === 'i') { e.preventDefault(); showToast('Import audio','info'); return; }
+                    if (ctrl && !alt && e.key === 'e') { e.preventDefault(); openTempTab(); return; }
+                    if (ctrl && !alt && e.key === 'm') { e.preventDefault(); handleMergeTracks(); return; }
+                    if (ctrl && !alt && e.key === 'c') { e.preventDefault(); handleCopyTrack(); return; }
+                    if (ctrl && !alt && e.key === 'x') { e.preventDefault(); handleCutTrack(); return; }
+                    if (ctrl && !alt && e.key === 'v') { e.preventDefault(); contextMenuPaste(); return; }
+                    if (e.key === 'Delete' || e.key === 'Del') { e.preventDefault(); handleDeleteTrack(); return; }
+                    if (!ctrl && !alt && e.key === 's') { e.preventDefault(); handleSplitTrack(selectedTrackId); return; }
                 };
-                window.addEventListener('keydown', handleKeyDown);
-                return () => window.removeEventListener('keydown', handleKeyDown);
-            }, []); // empty deps: refs avoid stale closure
+                window.addEventListener('keydown', handler);
+                return () => window.removeEventListener('keydown', handler);
+            }, []);
 
             // ── Temp Tab: draw isolated waveform ──
             useEffect(() => {