<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <style> .youtube-container { position: relative; padding-top: 56.25%; /* 16:9 aspect ratio */ overflow: hidden; } .youtube-container iframe { position: absolute; top: 0; left: 0; width: 100%; height: 100%; } </style> </head> <body> <div class="youtube-container"> <iframe src="https://www.youtube.com/embed/cKgN3XB6yM0?rel=0" frameborder="0" allowfullscreen></iframe> </div> </body> </html>