I want to create a responsive div that can change its width/height as the window's width changes. Are there any CSS rules that would allow the height to change according to the width, while maintaining its aspect ratio? I know I can do this via JavaScript, but I would prefer using only CSS.
![Maintain the aspect ratio of a div with CSS](https://cdn-ak-scissors.b.st-hatena.com/image/square/98d6f053a97a87156775f60757c60865d0f2c47d/height=288;version=1;width=512/https%3A%2F%2Fcdn.sstatic.net%2FSites%2Fstackoverflow%2FImg%2Fapple-touch-icon%402.png%3Fv%3D73d79a89bded)