UX Design and Development course

CSS media queries [syntax]

A media query consists of a media type and at least one expression that limits the style sheets' scope by using media features, such as width, height, and color. Media queries, added in CSS3, let the presentation of content be tailored to a specific range of output devices without having to change the content itself.

Syntax

https://developer.mozilla.org/en-US/docs/Web/Guide/CSS/Media_queries

Media queries consist of a media type and can, as of the CSS3 specification, contain one or more expressions, expressed as media features, which resolve to either true or false. The result of the query is true if the media type specified in the media query matches the type of device the document is being displayed on and all expressions in the media query are true.

<!-- CSS media query on a link element -->
<link rel="stylesheet" media="(max-width: 800px)" href="example.css" />

<!-- CSS media query within a style sheet -->
<style>
@media (max-width: 600px) {
  .facet_sidebar {
    display: none;
  }
}
</style>

When a media query is true, the corresponding style sheet or style rules are applied, following the normal cascading rules. Style sheets with media queries attached to their <link> tags will still download even if their media queries would return false (they will not apply, however).

Unless you use the not or only operators, the media type is optional and the all type will be implied.

and

The and keyword is used for combining multiple media features together, as well as combining media features with media types. A basic media query, a single media feature with the implied all media type, could look like this:

@media (min-width: 700px) { ... }

If, however, you wanted this to apply only if the display is in landscape, you could use an and operator to chain the media features together.

@media (min-width: 700px) and (orientation: landscape) { ... }

Now the above media query will only return true if the viewport is 700px wide or wider and the display is in landscape. If, however, you only wanted this to apply if the display in question was of the media type TV, you could chain these features with a media type using an and operator.

@media tv and (min-width: 700px) and (orientation: landscape) { ... }

Now, the above media query will only apply if the media type is TV, the viewport is 700px wide or wider, and the display is in landscape.

comma-separated lists

Comma-separated lists behave like the logical operator or when used in media queries. When using a comma-separated list of media queries, if any of the media queries returns true, the styles or style sheets get applied. Each media query in a comma-separated list is treated as an individual query, and any operator applied to one media query does not affect the others. This means the comma-separated media queries can target different media features, types, and states.

For instance, if you wanted to apply a set of styles if the viewing device either had a minimum width of 700px or was a handheld in landscape, you could write the following:

@media (min-width: 700px), handheld and (orientation: landscape) { ... }

Above, if I were on a screen device with a viewport width of 800px, the media statement would return true because the first part, interperated as @media all and (min-width: 700px) would apply to my device and therefore return true, despite the fact that my screen device would fail the handheld media type check in the second media query. Likewise, if I were on a handheld device held in landscape with a viewport width of 500px, while the first media query would fail due to the viewport width, the second media query would succeed and thus the media statement would return true.

not

The not keyword applies to the whole media query and returns true if the media query would otherwise return false (such as monochrome on a color display or a screen width of 600px with a min-width: 700px feature query). A not will only negate the media query it is applied to and not to every media query if present in a comma-separated list of media queries. The not keyword cannot be used to negate an individual feature query, only an entire media query. For example, the not is evaluated last in the following query:

@media not all and (monochrome) { ... }

This means that the query is evaluated like this:

@media not (all and (monochrome)) { ... }

... rather than like this:

@media (not all) and (monochrome) { ... }

As another example, look at the following media query:

@media not screen and (color), print and (color)

It is evaluated like this:

@media (not (screen and (color))), print and (color)

only

The only keyword prevents older browsers that do not support media queries with media features from applying the given styles:

<link rel="stylesheet" media="only screen and (color)" href="example.css" />

Media features

Most media features can be prefixed with "min-" or "max-" to express "greater or equal to" or "less than or equal to" constraints. This avoids using the "<" and ">" symbols, which would conflict with HTML and XML. If you use a media feature without specifying a value, the expression resolves to true if the feature's value is non-zero.

color

Value: <color> Media: visual Accepts min/max prefixes: yes

Indicates the number of bits per color component of the output device. If the device is not a color device, this value is zero

color-index

Value: <integer> Media: visual Accepts min/max prefixes: yes

Indicates the number of entries in the color look-up table for the output device.

aspect-ratio

Value: <ratio> Media: visual, tactile Accepts min/max prefixes: yes

Describes the aspect ratio of the targeted display area of the output device. This value consists of two positive integers separated by a slash ("/") character. This represents the ratio of horizontal pixels (first term) to vertical pixels (second term).

device-aspect-ratio

Value: <ratio> Media: visual, tactile Accepts min/max prefixes: yes

Describes the aspect ratio of the output device. This value consists of two positive integers separated by a slash ("/") character. This represents the ratio of horizontal pixels (first term) to vertical pixels (second term).

device-height

Value: <length> Media: visual, tactile Accepts min/max prefixes: yes

Describes the height of the output device (meaning the entire screen or page, rather than just the rendering area, such as the document window).

device-width

Value: <length> Media: visual, tactile Accepts min/max prefixes: yes

Describes the width of the output device (meaning the entire screen or page, rather than just the rendering area, such as the document window).

For more media types and code examples, refer to the full article.

Media queries on SassMeister

Play with this gist on SassMeister.

The dream -- Bandwidth queries

The same says it all. This is the dream of many developers. What if we could query the actual bandwidth of the user? We cold then make smarter decisions about what to send them as far as features and content.

Are we there yet? No. But Chris does a great way of speculating what this world would look like.

http://css-tricks.com/bandwidth-media-queries/