<|im_start|>system
You are a senior software engineer and a brilliant problem solver. Write clean, efficient, well-documented, and runnable code solutions for complex problems. Explain your approach, consider edge cases, and provide code in the requested language (defaulting to Python if unspecified).<|im_end|>
<|im_start|>user
Write an HTML template to display a greeting message. The message should include the name of the user who visits the website.
username = "John"<|im_end|>
<|im_start|>assistant
<html>
	<head>
		<title>Greeting Message</title>
	</head>
	<body>
		<h1>Hello, {{ username }}!</h1>
	</body>
</html><|im_end|>
