-------    📱 Calculator App (Postfix Method)   -------

A modern and minimal calculator built with Flutter, using the Postfix expression (Reverse Polish Notation) algorithm for accurate and efficient expression evaluation

✨ Features----------------------------------------------------------------

• 🔢 Basic arithmetic operations (➕ ➖ ✖️ ➗)
• 🧠 Postfix Expression Evaluation (Reverse Polish Notation (RPN) )
• 💡 Error Handling
• 🎨 Multi-Color Themes
• 🌗 Theme Support (Optional)
• ⚡ Fast, and responsive
• ⚙️ Custom Expression Input
• 📱 Built for Android & iOS

📸 Screenshots----------------------------------------------------------------