Add placeholder app, frame

main.py

@@ -0,0 +1,48 @@
+import customtkinter as ctk
+
+MAIN_RED = "#eb4034"
+RED_HOVER = "#f75a4f"
+
+ctk.set_appearance_mode("dark")
+ctk.set_default_color_theme("blue")
+
+
+class PomodoroFrame(ctk.CTkFrame):
+    def __init__(self, master, start_func):
+        super().__init__(master)
+
+        # Placeholder
+        self.timer_display = ctk.CTkLabel(self, text="00:25:00", font=("Helvetica", 48))
+        self.timer_display.pack(pady=50)
+
+        self.start_button = ctk.CTkButton(self, text="Start", fg_color="transparent", border_color=MAIN_RED,
+                                          border_width=2, corner_radius=32, hover_color=RED_HOVER, command=start_func)
+        self.start_button.pack()
+
+
+class PomodoroApp(ctk.CTk):
+    WIDTH = 400
+    HEIGHT = 400
+
+    def __init__(self):
+        super().__init__()
+
+        self.title("Pomodoro Tracker")
+        self.geometry(f"{PomodoroApp.WIDTH}x{PomodoroApp.HEIGHT}")
+
+        tabview = ctk.CTkTabview(master=self)
+        tabview.pack(padx=20, pady=20)
+
+        tabview.add("Main")
+        tabview.add("Settings")
+
+        self.main_frame = PomodoroFrame(tabview.tab("Main"), self.start_timer)
+        self.main_frame.pack()
+
+    def start_timer(self):
+        print("Timer started")
+
+
+if __name__ == "__main__":
+    app = PomodoroApp()
+    app.mainloop()