diff --git a/README.md b/README.md
index 0c4a707..404648e 100644
--- a/README.md
+++ b/README.md
@@ -1 +1,17 @@
-# MyFirst
\ No newline at end of file
+# MyFirst
+
+A simple calculator built with Python and a cute pastel-colored UI using Tkinter.
+
+## Run
+
+```bash
+python calculator.py
+```
+
+## Features
+
+- Basic arithmetic (`+`, `-`, `*`, `/`, `%`)
+- Decimal support
+- Parentheses support
+- Clear (`C`) and backspace (`⌫`) controls
+- Friendly error message for invalid expressions
diff --git a/calculator.py b/calculator.py
new file mode 100644
index 0000000..56d7ce8
--- /dev/null
+++ b/calculator.py
@@ -0,0 +1,110 @@
+import tkinter as tk
+
+
+class CuteCalculator:
+    def __init__(self, root: tk.Tk) -> None:
+        self.root = root
+        self.root.title("Cute Calculator")
+        self.root.geometry("340x500")
+        self.root.configure(bg="#ffe6f2")
+        self.root.resizable(False, False)
+
+        self.expression = ""
+
+        self.display_var = tk.StringVar(value="0")
+
+        display = tk.Entry(
+            root,
+            textvariable=self.display_var,
+            font=("Comic Sans MS", 28, "bold"),
+            bd=0,
+            relief="flat",
+            justify="right",
+            bg="#fff8fc",
+            fg="#6b3f5b",
+            insertbackground="#6b3f5b",
+        )
+        display.pack(fill="x", padx=18, pady=(24, 14), ipady=16)
+
+        button_frame = tk.Frame(root, bg="#ffe6f2")
+        button_frame.pack(expand=True, fill="both", padx=14, pady=(4, 16))
+
+        rows = [
+            ["C", "⌫", "%", "/"],
+            ["7", "8", "9", "*"],
+            ["4", "5", "6", "-"],
+            ["1", "2", "3", "+"],
+            ["0", ".", "=", "("],
+        ]
+
+        # Add closing bracket as a cute floating button near bottom right.
+        close_btn = tk.Button(
+            root,
+            text=")",
+            font=("Comic Sans MS", 16, "bold"),
+            bg="#d6f5ff",
+            fg="#4a6470",
+            bd=0,
+            activebackground="#b8ebff",
+            activeforeground="#4a6470",
+            command=lambda: self.on_click(")"),
+        )
+        close_btn.place(x=280, y=450, width=40, height=34)
+
+        for r in range(5):
+            button_frame.grid_rowconfigure(r, weight=1)
+            for c in range(4):
+                button_frame.grid_columnconfigure(c, weight=1)
+                label = rows[r][c]
+                btn = tk.Button(
+                    button_frame,
+                    text=label,
+                    font=("Comic Sans MS", 18, "bold"),
+                    bd=0,
+                    relief="flat",
+                    command=lambda x=label: self.on_click(x),
+                )
+
+                if label in {"/", "*", "-", "+", "=", "%"}:
+                    btn.configure(bg="#ffd6eb", fg="#7f3b65", activebackground="#ffc2e1")
+                elif label in {"C", "⌫"}:
+                    btn.configure(bg="#fff0b3", fg="#7f6200", activebackground="#ffe98a")
+                else:
+                    btn.configure(bg="#d6f5ff", fg="#34505b", activebackground="#b8ebff")
+
+                btn.grid(row=r, column=c, sticky="nsew", padx=6, pady=6, ipady=8)
+
+    def on_click(self, char: str) -> None:
+        if char == "C":
+            self.expression = ""
+            self.display_var.set("0")
+        elif char == "⌫":
+            self.expression = self.expression[:-1]
+            self.display_var.set(self.expression if self.expression else "0")
+        elif char == "=":
+            self.calculate()
+        else:
+            self.expression += char
+            self.display_var.set(self.expression)
+
+    def calculate(self) -> None:
+        if not self.expression:
+            return
+
+        try:
+            allowed = set("0123456789+-*/%.() ")
+            if any(ch not in allowed for ch in self.expression):
+                raise ValueError("Invalid characters")
+
+            result = eval(self.expression, {"__builtins__": {}}, {})
+            self.expression = str(result)
+            self.display_var.set(self.expression)
+        except Exception:
+            self.expression = ""
+            self.display_var.set("Oops! Try again 💖")
+
+
+if __name__ == "__main__":
+    root = tk.Tk()
+    CuteCalculator(root)
+    root.mainloop()