diff --git a/calc.py b/calc.py
index 758bc87..5f8e5a2 100644
--- a/calc.py
+++ b/calc.py
@@ -1,4 +1,5 @@
 import tkinter as tk
+from tkinter import ttk
 
 LARGE_FONT_STYLE = ("Arial", 40, "bold")
 SMALL_FONT_STYLE = ("Arial", 16)
@@ -11,6 +12,11 @@
 LIGHT_GRAY = "#F5F5F5"
 LABEL_COLOR = "#25265E"
 
+# Constantes pour les textes des boutons
+CLEAR_BUTTON_TEXT = "C"
+SQUARE_BUTTON_TEXT = "x\u00b2"
+SQRT_BUTTON_TEXT = "\u221ax"
+EQUALS_BUTTON_TEXT = "="
 
 class Calculator:
     def __init__(self):
@@ -18,12 +24,39 @@ def __init__(self):
         self.window.geometry("375x667")
         self.window.resizable(0, 0)
         self.window.title("Calculator")
+        self.style = ttk.Style(self.window)
+        self.style.theme_use("clam")
 
         self.total_expression = ""
         self.current_expression = ""
-        self.display_frame = self.create_display_frame()
 
-        self.total_label, self.label = self.create_display_labels()
+        self.create_widgets()
+        self.bind_keys()
+
+    def create_widgets(self):
+        self.create_display()
+        self.create_buttons()
+
+    def create_display(self):
+        self.display_frame = tk.Frame(self.window, height=221, bg=LIGHT_GRAY)
+        self.display_frame.pack(expand=True, fill="both")
+
+        self.total_label = tk.Label(self.display_frame, text=self.total_expression, anchor=tk.E, bg=LIGHT_GRAY,
+                               fg=LABEL_COLOR, padx=24, font=SMALL_FONT_STYLE)
+        self.total_label.pack(expand=True, fill='both')
+
+        self.label = tk.Label(self.display_frame, text=self.current_expression, anchor=tk.E, bg=LIGHT_GRAY,
+                         fg=LABEL_COLOR, padx=24, font=LARGE_FONT_STYLE)
+        self.label.pack(expand=True, fill='both')
+
+    def create_buttons(self):
+        self.buttons_frame = tk.Frame(self.window)
+        self.buttons_frame.pack(expand=True, fill="both")
+
+        self.buttons_frame.rowconfigure(0, weight=1)
+        for x in range(1, 5):
+            self.buttons_frame.rowconfigure(x, weight=1)
+            self.buttons_frame.columnconfigure(x, weight=1)
 
         self.digits = {
             7: (1, 1), 8: (1, 2), 9: (1, 3),
@@ -32,71 +65,59 @@ def __init__(self):
             0: (4, 2), '.': (4, 1)
         }
         self.operations = {"/": "\u00F7", "*": "\u00D7", "-": "-", "+": "+"}
-        self.buttons_frame = self.create_buttons_frame()
 
-        self.buttons_frame.rowconfigure(0, weight=1)
-        for x in range(1, 5):
-            self.buttons_frame.rowconfigure(x, weight=1)
-            self.buttons_frame.columnconfigure(x, weight=1)
         self.create_digit_buttons()
         self.create_operator_buttons()
         self.create_special_buttons()
-        self.bind_keys()
+
+    def create_button(self, frame, text, bg, fg, font, command, row, column, columnspan=1, sticky="nsew"):
+        button = ttk.Button(frame, text=text, command=command)
+        self.style.configure(f"TButton", background=bg, foreground=fg, font=font)
+        button.grid(row=row, column=column, columnspan=columnspan, sticky=sticky)
+        return button
+
+    def create_digit_buttons(self):
+        for digit, grid_value in self.digits.items():
+            self.create_button(self.buttons_frame, str(digit), WHITE, LABEL_COLOR, DIGITS_FONT_STYLE,
+                               lambda x=digit: self.add_to_expression(x), grid_value[0], grid_value[1])
+
+    def create_operator_buttons(self):
+        i = 0
+        for operator, symbol in self.operations.items():
+            self.create_button(self.buttons_frame, symbol, OFF_WHITE, LABEL_COLOR, DEFAULT_FONT_STYLE,
+                               lambda x=operator: self.append_operator(x), i, 4)
+            i += 1
+
+    def create_special_buttons(self):
+        self.create_button(self.buttons_frame, CLEAR_BUTTON_TEXT, OFF_WHITE, LABEL_COLOR, DEFAULT_FONT_STYLE,
+                           self.clear, 0, 1)
+        self.create_button(self.buttons_frame, EQUALS_BUTTON_TEXT, LIGHT_BLUE, LABEL_COLOR, DEFAULT_FONT_STYLE,
+                           self.evaluate, 4, 3, columnspan=2)
+        self.create_button(self.buttons_frame, SQUARE_BUTTON_TEXT, OFF_WHITE, LABEL_COLOR, DEFAULT_FONT_STYLE,
+                           self.square, 0, 2)
+        self.create_button(self.buttons_frame, SQRT_BUTTON_TEXT, OFF_WHITE, LABEL_COLOR, DEFAULT_FONT_STYLE,
+                           self.sqrt, 0, 3)
+        self.create_button(self.buttons_frame, "⌫", OFF_WHITE, LABEL_COLOR, DEFAULT_FONT_STYLE,
+                           self.backspace, 4, 1)  # Ajout du bouton Backspace
 
     def bind_keys(self):
         self.window.bind("<Return>", lambda event: self.evaluate())
+        self.window.bind("<BackSpace>", lambda event: self.backspace())  # Bind pour backspace
         for key in self.digits:
             self.window.bind(str(key), lambda event, digit=key: self.add_to_expression(digit))
-
         for key in self.operations:
             self.window.bind(key, lambda event, operator=key: self.append_operator(operator))
 
-    def create_special_buttons(self):
-        self.create_clear_button()
-        self.create_equals_button()
-        self.create_square_button()
-        self.create_sqrt_button()
-
-    def create_display_labels(self):
-        total_label = tk.Label(self.display_frame, text=self.total_expression, anchor=tk.E, bg=LIGHT_GRAY,
-                               fg=LABEL_COLOR, padx=24, font=SMALL_FONT_STYLE)
-        total_label.pack(expand=True, fill='both')
-
-        label = tk.Label(self.display_frame, text=self.current_expression, anchor=tk.E, bg=LIGHT_GRAY,
-                         fg=LABEL_COLOR, padx=24, font=LARGE_FONT_STYLE)
-        label.pack(expand=True, fill='both')
-
-        return total_label, label
-
-    def create_display_frame(self):
-        frame = tk.Frame(self.window, height=221, bg=LIGHT_GRAY)
-        frame.pack(expand=True, fill="both")
-        return frame
-
     def add_to_expression(self, value):
         self.current_expression += str(value)
         self.update_label()
 
-    def create_digit_buttons(self):
-        for digit, grid_value in self.digits.items():
-            button = tk.Button(self.buttons_frame, text=str(digit), bg=WHITE, fg=LABEL_COLOR, font=DIGITS_FONT_STYLE,
-                               borderwidth=0, command=lambda x=digit: self.add_to_expression(x))
-            button.grid(row=grid_value[0], column=grid_value[1], sticky=tk.NSEW)
-
     def append_operator(self, operator):
-        self.current_expression += operator
-        self.total_expression += self.current_expression
-        self.current_expression = ""
-        self.update_total_label()
-        self.update_label()
-
-    def create_operator_buttons(self):
-        i = 0
-        for operator, symbol in self.operations.items():
-            button = tk.Button(self.buttons_frame, text=symbol, bg=OFF_WHITE, fg=LABEL_COLOR, font=DEFAULT_FONT_STYLE,
-                               borderwidth=0, command=lambda x=operator: self.append_operator(x))
-            button.grid(row=i, column=4, sticky=tk.NSEW)
-            i += 1
+        if self.current_expression:  # Empêche d'ajouter un opérateur si current_expression est vide
+            self.total_expression += self.current_expression + operator
+            self.current_expression = ""
+            self.update_total_label()
+            self.update_label()
 
     def clear(self):
         self.current_expression = ""
@@ -104,50 +125,42 @@ def clear(self):
         self.update_label()
         self.update_total_label()
 
-    def create_clear_button(self):
-        button = tk.Button(self.buttons_frame, text="C", bg=OFF_WHITE, fg=LABEL_COLOR, font=DEFAULT_FONT_STYLE,
-                           borderwidth=0, command=self.clear)
-        button.grid(row=0, column=1, sticky=tk.NSEW)
-
-    def square(self):
-        self.current_expression = str(eval(f"{self.current_expression}**2"))
-        self.update_label()
-
-    def create_square_button(self):
-        button = tk.Button(self.buttons_frame, text="x\u00b2", bg=OFF_WHITE, fg=LABEL_COLOR, font=DEFAULT_FONT_STYLE,
-                           borderwidth=0, command=self.square)
-        button.grid(row=0, column=2, sticky=tk.NSEW)
-
-    def sqrt(self):
-        self.current_expression = str(eval(f"{self.current_expression}**0.5"))
+    def backspace(self):  # Fonction pour effacer le dernier caractère
+        self.current_expression = self.current_expression[:-1]
         self.update_label()
 
-    def create_sqrt_button(self):
-        button = tk.Button(self.buttons_frame, text="\u221ax", bg=OFF_WHITE, fg=LABEL_COLOR, font=DEFAULT_FONT_STYLE,
-                           borderwidth=0, command=self.sqrt)
-        button.grid(row=0, column=3, sticky=tk.NSEW)
-
-    def evaluate(self):
-        self.total_expression += self.current_expression
-        self.update_total_label()
+    def square(self):
         try:
-            self.current_expression = str(eval(self.total_expression))
-
-            self.total_expression = ""
-        except Exception as e:
+            self.current_expression = str(eval(f"{self.current_expression}**2"))
+        except (SyntaxError, TypeError, ValueError):
             self.current_expression = "Error"
         finally:
             self.update_label()
 
-    def create_equals_button(self):
-        button = tk.Button(self.buttons_frame, text="=", bg=LIGHT_BLUE, fg=LABEL_COLOR, font=DEFAULT_FONT_STYLE,
-                           borderwidth=0, command=self.evaluate)
-        button.grid(row=4, column=3, columnspan=2, sticky=tk.NSEW)
+    def sqrt(self):
+        try:
+            value = eval(self.current_expression)
+            if value >= 0:
+                self.current_expression = str(value**0.5)
+            else:
+                self.current_expression = "Error: Racine carrée de nombre négatif"
+        except (SyntaxError, TypeError, ValueError, ZeroDivisionError) as e:
+            self.current_expression = f"Error: {e}"
+        finally:
+            self.update_label()
 
-    def create_buttons_frame(self):
-        frame = tk.Frame(self.window)
-        frame.pack(expand=True, fill="both")
-        return frame
+    def evaluate(self):
+        if self.current_expression:  # Permet d'effectuer un calcul avec seulement current_expression
+            self.total_expression += self.current_expression
+        if self.total_expression:  # Vérifie si total_expression n'est pas vide avant d'évaluer
+            self.update_total_label()
+            try:
+                self.current_expression = str(eval(self.total_expression))
+                self.total_expression = ""
+            except (SyntaxError, TypeError, ValueError, ZeroDivisionError) as e:
+                self.current_expression = f"Error: {e}"
+            finally:
+                self.update_label()
 
     def update_total_label(self):
         expression = self.total_expression
@@ -156,12 +169,11 @@ def update_total_label(self):
         self.total_label.config(text=expression)
 
     def update_label(self):
-        self.label.config(text=self.current_expression[:11])
+        self.label.config(text=self.current_expression)
 
     def run(self):
         self.window.mainloop()
 
-
 if __name__ == "__main__":
     calc = Calculator()
     calc.run()