<!doctype html> <html> <head> <meta charset="utf-8"> <title>Simple Custom Responsive Grid Layout</title> <meta name="viewport" content="width=device-width, initial-scale=1"> <link rel="stylesheet" type="text/css" href="style.css"> </head> <body> <div class="left-column" style="background-color: yellow"> View this page on devices with screen width larger than 767px and also on devices with screen width less than 767px. </div><!-- --><div class="right-column" style="background-color: aqua"> You can use Chrome "Device Mode and Mobile Emulation" to view this page as mobile devices </div> </body> </html>