diff --git a/development-tools/index.rst b/development-tools/index.rst
index b564c933e..b62c5f801 100644
--- a/development-tools/index.rst
+++ b/development-tools/index.rst
@@ -1,13 +1,111 @@
-.. _development-tools:
+import openpyxl
+from openpyxl import Workbook
+from openpyxl.styles import Font, Alignment, Border, Side, PatternFill
 
-=================
-Development tools
-=================
+# Crear libro
+wb = Workbook()
 
-.. toctree::
-   :maxdepth: 5
+# === Estilos ===
+bold = Font(bold=True)
+center = Alignment(horizontal="center", vertical="center")
+thin_border = Border(
+    left=Side(style="thin"),
+    right=Side(style="thin"),
+    top=Side(style="thin"),
+    bottom=Side(style="thin")
+)
+fill_header = PatternFill(start_color="D9E1F2", end_color="D9E1F2", fill_type="solid")
 
-   clinic/index
-   gdb
-   clang
-   warnings
+# --- Hoja 1: Libro Diario ---
+ws1 = wb.active
+ws1.title = "Libro Diario"
+
+# Encabezados
+headers = ["Fecha", "Cuenta", "Débito", "Crédito"]
+ws1.append(headers)
+
+# Aplicar formato a encabezados
+for col in range(1, 5):
+    cell = ws1.cell(row=1, column=col)
+    cell.font = bold
+    cell.alignment = center
+    cell.fill = fill_header
+    cell.border = thin_border
+
+# Transacciones
+transacciones = [
+    ("01/10/2025", "Caja", 1500, ""),
+    ("", "Capital Social", "", 1500),
+    ("", "SUMAS IGUALES", 1500, 1500),
+
+    ("02/10/2025", "Bancos", 800, ""),
+    ("", "Caja", "", 800),
+    ("", "SUMAS IGUALES", 800, 800),
+
+    ("03/10/2025", "Inventario Mercancías", 1200, ""),
+    ("", "Proveedores", "", 1200),
+    ("", "SUMAS IGUALES", 1200, 1200),
+
+    ("04/10/2025", "Proveedores", 500, ""),
+    ("", "Bancos", "", 500),
+    ("", "SUMAS IGUALES", 500, 500),
+
+    ("05/10/2025", "Gastos de Administración", 300, ""),
+    ("", "Caja", "", 300),
+    ("", "SUMAS IGUALES", 300, 300),
+
+    ("", "TOTALES GENERALES", 4300, 4300),
+]
+
+for fila in transacciones:
+    ws1.append(fila)
+
+# Formato general
+for row in ws1.iter_rows(min_row=2, max_row=ws1.max_row, min_col=1, max_col=4):
+    for cell in row:
+        cell.border = thin_border
+        if cell.column in (3, 4):  # Débito y Crédito
+            cell.alignment = Alignment(horizontal="right")
+        else:
+            cell.alignment = Alignment(horizontal="left")
+
+# Ajustar ancho de columnas
+col_widths = [12, 30, 15, 15]
+for i, width in enumerate(col_widths, 1):
+    ws1.column_dimensions[openpyxl.utils.get_column_letter(i)].width = width
+
+
+# --- Hoja 2: Balance de Prueba ---
+ws2 = wb.create_sheet(title="Balance de Prueba")
+
+headers2 = ["Cuenta", "Débito", "Crédito"]
+ws2.append(headers2)
+
+for col in range(1, 4):
+    cell = ws2.cell(row=1, column=col)
+    cell.font = bold
+    cell.alignment = center
+    cell.fill = fill_header
+    cell.border = thin_border
+
+balance = [
+    ("Caja", 700, ""),
+    ("Bancos", 300, ""),
+    ("Inventario Mercancías", 1200, ""),
+    ("Proveedores", "", 700),
+    ("Gastos de Administración", 300, ""),
+    ("Capital Social", "", 1500),
+    ("TOTALES", 2500, 2500),
+]
+
+for fila in balance:
+    ws2.append(fila)
+
+# Formato general hoja 2
+for row in ws2.iter_rows(min_row=2, max_row=ws2.max_row, min_col=1, max_col=3):
+    for cell in row:
+        cell.border = thin_border
+        if cell.column in (2, 3):
+            cell.alignment = Alignment(horizontal="right")
+        else:
+            cell.alignment = Alignment(