<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>Hello World</title> <style> html, body { height: 100%; margin: 0; padding: 0; display: flex; align-items: center; justify-content: center; font-family: Arial, sans-serif; } </style> </head> <body> <h1>Hello World</h1> </body> </html>