[css] Can media queries resize based on a div element instead of the screen?

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 just used like a widget within the webpage, and its size can vary.

Update

Looks like there is work being done on this now: https://github.com/ResponsiveImagesCG/cq-demos

I was also thinking of media queries, but then I found this:

• http://www.mademyday.de/css-height-equals-width-with-pure-css.html
• Maintain the aspect ratio of a div with CSS

Just create a wrapper <div> with a percentage value for padding-bottom, like this:

div {_x000D_
  width: 100%;_x000D_
  padding-bottom: 75%;_x000D_
  background:gold; /** <-- For the demo **/_x000D_
}

<div></div>

It will result in a <div> with height equal to 75% of the width of its container (a 4:3 aspect ratio).

This technique can also be coupled with media queries and a bit of ad hoc knowledge about page layout for even more finer-grained control.

It's enough for my needs. Which might be enough for your needs too.

For mine I did it by setting the div's max width, hence for small widget won't get affected and the large widget is resized due to the max-width style.

  // assuming your widget class is "widget"
  .widget {
    max-width: 100%;
    height: auto;
  }

I've just created a javascript shim to achieve this goal. Take a look if you want, it's a proof-of-concept, but take care: it's a early version and still needs some work.

https://github.com/marcj/css-element-queries

This is currently not possible with CSS alone as @BoltClock wrote in the accepted answer, but you can work around that by using JavaScript.

I created a container query (aka element query) prolyfill to solve this kind of issue. It works a bit different than other scripts, so you don’t have to edit the HTML code of your elements. All you have to do is include the script and use it in your CSS like so:

.element:container(width > 99px) {
    /* If its container is at least 100px wide */
}

https://github.com/ausi/cq-prolyfill

From a layout perspective, it is possible using modern techniques.

Its made up (I believe) by Heydon Pickering. He details the process here: http://www.heydonworks.com/article/the-flexbox-holy-albatross

Chris Coyier picks it up and works through a demo of it here: https://css-tricks.com/putting-the-flexbox-albatross-to-real-use/

To restate the issue, below we see 3 of the same component, each made up of three orange divs labelled a, b and c.

The second two's blocks display vertically, because they are limited on horizontal room, while the top components 3 blocks are laid out horizontally.

It uses the flex-basis CSS property and CSS Variables to create this effect.

.panel{
  display: flex;
  flex-wrap: wrap;
  border: 1px solid #f00;
  $breakpoint: 600px;
  --multiplier: calc( #{$breakpoint} - 100%);
  .element{
    min-width: 33%;
    max-width: 100%;
    flex-grow: 1;
    flex-basis: calc( var(--multiplier) * 999 );
  }
}

Demo

Heydon's article is 1000 words explaining it in detail, and I'd highly recommend reading it.

The only way I can think that you can accomplish what you want purely with css, is to use a fluid container for your widget. If your container's width is a percentage of the screen then you can use media queries to style depending on your container's width, as you will now know for each screen's dimensions what is your container's dimensions. For example, let's say you decide to make your container's 50% of the screen width. Then for a screen width of 1200px you know that your container is 600px

.myContainer {
  width: 50%;
}

/* you know know that your container is 600px 
 * so you style accordingly
*/
@media (max-width: 1200px) { 
  /* your css for 600px container */
}

You can use the ResizeObserver API. It's still in it's early days so it's not supported by all browsers yet (but there several polyfills that can help you with that).

Basically this API allow you to attach an event listener to the resize of a DOM element.

Demo 1 - Demo 2

The question is very vague. As BoltClock says, media queries only know the dimensions of the device. However, you can use media queries in combination with descender selectors to perform adjustments.

.wide_container { width: 50em }

.narrow_container { width: 20em }

.my_element { border: 1px solid }

@media (max-width: 30em) {
    .wide_container .my_element {
        color: blue;
    }

    .narrow_container .my_element {
        color: red;
    }
}

@media (max-width: 50em) {
    .wide_container .my_element {
        color: orange;
    }

    .narrow_container .my_element {
        color: green;
    }
}

The only other solution requires JS.

I ran into the same problem a couple of years ago and funded the development of a plugin to help me in my work. I've released the plugin as open-source so others can benefit from it as well, and you can grab it on Github: https://github.com/eqcss/eqcss

There are a few ways we could apply different responsive styles based on what we can know about an element on the page. Here are a few element queries that the EQCSS plugin will let you write in CSS:

@element 'div' and (condition) {
  $this {
    /* Do something to the 'div' that meets the condition */
  }
  .other {
    /* Also apply this CSS to .other when 'div' meets this condition */
  }
}

So what conditions are supported for responsive styles with EQCSS?

Weight Queries

• min-width in px
• min-width in %
• max-width in px
• max-width in %

Height Queries

• min-height in px
• min-height in %
• max-height in px
• max-height in %

Count Queries

• min-characters
• max-characters
• min-lines
• max-lines
• min-children
• max-children

Special Selectors

Inside EQCSS element queries you can also use three special selectors that allow you to more specifically apply your styles:

• $this (the element(s) matching the query)
• $parent (the parent element(s) of the element(s) matching the query)
• $root (the root element of the document, <html>)

Element queries allow you to compose your layout out of individually responsive design modules, each with a bit of 'self-awareness' of how they are being displayed on the page.

With EQCSS you can design one widget to look good from 150px wide all the way up to 1000px wide, then you can confidently drop that widget into any sidebar in any page using any template (on any site) and

A Media Query inside of an iframe can function as an element query. I've successfully implement this. The idea came from a recent post about Responsive Ads by Zurb. No Javascript!