How can media queries in CSS be effectively used to create responsive design without the need for PHP screen width detection?

Media queries in CSS can be effectively used to create responsive design by specifying different styles based on the screen width. This eliminates the need for PHP screen width detection, as the styles will automatically adjust based on the device's screen size. ```css /* CSS */ @media only screen and (max-width: 600px) { /* Styles for screens up to 600px wide */ } @media only screen and (min-width: 601px) { /* Styles for screens wider than 600px */ } ```