<!DOCTYPE html><html lang="en"><head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>Income Tax Calculator</title> <style> body { font-family: Arial, sans-serif; text-align: center; margin: 50px; } .container { max-width: 400px; margin: auto; padding: 20px; border: 1px solid...