<!DOCTYPE html> <html lang="en"> <head> <meta charset="utf-8"> <title>CSS Grouping Selectors</title> <style> h1, h2, h3 { font-weight: normal; } h1 { font-size: 30px; } h2 { font-size: 25px; } h3 { font-size: 20px; } </style> </head> <body> <h1>This is main heading.</h1> <h2>This is a next heading.</h2> <h3>This is a sub heading.</h3></body> </html>