I would like to use media queries to resize elements based on the size of a div
element they are in. I cannot use the screen size as the div
is jus
No, media queries aren't designed to work based on elements in a page. They are designed to work based on devices or media types (hence why they are called media queries). width, height, and other dimension-based media features all refer to the dimensions of either the viewport or the device's screen in screen-based media. They cannot be used to refer to a certain element on a page.
If you need to apply styles depending on the size of a certain div
element on your page, you'll have to use JavaScript to observe changes in the size of that div
element instead of media queries.
Alternatively, with more modern layout techniques introduced since the original publication of this answer such as flexbox and standards such as custom properties, you may not need media or element queries after all. Djave provides an example.