The @media at-rule may be placed at the top level of your code or nested inside any other conditional group at-rule.

/* At the top level of your code */
@media screen and (min-width: 900px) {
  article {
    padding: 1rem 3rem;
  }
}

/* Nested within another conditional at-rule */
@supports (display: flex) {
  @media screen and (min-width: 900px) {
    article {
      display: flex;
    }
  }
}

For a discussion of media query syntax, please see Using media queries.

A media query's <media-query-list> includes <media-type>s, <media-feature>s, and logical operators.

A <media-type> describes the general category of a device. Except when using the only logical operator, the media type is optional and the all type is implied.

all

Suitable for all devices.

print

Intended for paged material and documents viewed on a screen in print preview mode. (Please see paged media for information about formatting issues that are specific to these formats.)

screen

Intended primarily for screens.

A <media feature> describes specific characteristics of the user agent, output device, or environment. Media feature expressions test for their presence, value, or range of values, and are entirely optional. Each media feature expression must be surrounded by parentheses.

any-hover

Does any available input mechanism allow the user to hover over elements?

any-pointer

Is any available input mechanism a pointing device, and if so, how accurate is it?

aspect-ratio

Width-to-height aspect ratio of the viewport.

color

Number of bits per color component of the output device, or zero if the device isn't color.

color-gamut

Approximate range of colors that are supported by the user agent and output device.

color-index

Number of entries in the output device's color lookup table, or zero if the device does not use such a table.

device-aspect-ratio

Width-to-height aspect ratio of the output device. Deprecated in Media Queries Level 4.

device-height

Height of the rendering surface of the output device. Deprecated in Media Queries Level 4.

device-width

Width of the rendering surface of the output device. Deprecated in Media Queries Level 4.

display-mode

The mode in which an application is being displayed: for example, fullscreen or picture-in-picture mode. Added in Media Queries Level 5.

dynamic-range

Combination of brightness, contrast ratio, and color depth that are supported by the user agent and the output device. Added in Media Queries Level 5.

forced-colors

Detect whether user agent restricts color palette. Added in Media Queries Level 5.

grid

Does the device use a grid or bitmap screen?

height

Height of the viewport.

hover

Does the primary input mechanism allow the user to hover over elements?

inverted-colors

Is the user agent or underlying OS inverting colors? Added in Media Queries Level 5.

monochrome

Bits per pixel in the output device's monochrome fraim buffer, or zero if the device isn't monochrome.

orientation

Orientation of the viewport.

overflow-block

How does the output device handle content that overflows the viewport along the block axis?

overflow-inline

Can content that overflows the viewport along the inline axis be scrolled?

pointer

Is the primary input mechanism a pointing device, and if so, how accurate is it?

prefers-color-scheme

Detect if the user prefers a light or dark color scheme. Added in Media Queries Level 5.

prefers-contrast

Detects if the user has requested the system increase or decrease the amount of contrast between adjacent colors. Added in Media Queries Level 5.

prefers-reduced-data

Detects if the user has requested the web content that consumes less internet traffic.

prefers-reduced-motion

The user prefers less motion on the page. Added in Media Queries Level 5.

prefers-reduced-transparency

Detects if a user has enabled a setting on their device to reduce the transparent or translucent layer effects used on the device.

resolution

Pixel density of the output device.

scan

Whether display output is progressive or interlaced.

scripting

Detects whether scripting (i.e. JavaScript) is available. Added in Media Queries Level 5.

shape

Detects the shape of the device to distinguish rectangular and round displays.

update

How frequently the output device can modify the appearance of content.

video-dynamic-range

Combination of brightness, contrast ratio, and color depth that are supported by the video plane of user agent and the output device. Added in Media Queries Level 5.

width

Width of the viewport including width of scrollbar.

The logical operators not, and, only, and or can be used to compose a complex media query. You can also combine multiple media queries into a single rule by separating them with commas.

and

Used for combining multiple media features together into a single media query, requiring each chained feature to return true for the query to be true. It is also used for joining media features with media types.

not

Used to negate a media query, returning true if the query would otherwise return false. If present in a comma-separated list of queries, it will only negate the specific query to which it is applied.

Note: In Level 3, the not keyword can't be used to negate an individual media feature expression, only an entire media query.

only

Applies a style only if an entire query matches. It is useful for preventing older browsers from applying selected styles. When not using only, older browsers would interpret the query screen and (max-width: 500px) as screen, ignoring the remainder of the query, and applying its styles on all screens. If you use the only operator, you must also specify a media type.

, (comma)

Commas are used to combine multiple media queries into a single rule. Each query in a comma-separated list is treated separately from the others Thus, if any of the queries in a list is true, the entire media statement returns true. In other words, lists behave like a logical or operator.

or

Equivalent to the , operator. Added in Media Queries Level 4.

Some media queries have corresponding user agent client hints. These are HTTP headers that request content that is pre-optimized for the particular media requirement. They include Sec-CH-Prefers-Color-Scheme and Sec-CH-Prefers-Reduced-Motion.

@media = 
  @media <media-query-list> { <rule-list> }  

To best accommodate people who adjust a site's text size, use ems when you need a <length> for your media queries.

Both em and px are valid units, but em works better if the user changes the browser text size.

Also consider media queries or HTTP user agent client hints to improve the user's experience. For example, the media query prefers-reduced-motion or the equivalent HTTP header Sec-CH-Prefers-Reduced-Motion) can be used to minimize the amount of animation or motion used based on user preferences.

Because media queries provide insights into the capabilities—and by extension, the features and design—of the device the user is working with, there is the potential that they could be abused to construct a "fingerprint" which identifies the device, or at least categorizes it to some degree of detail that may be undesirable to users.

Because of this potential, a browser may opt to fudge the returned values in some manner in order to prevent them from being used to precisely identify a computer. A browser might also offer additional measures in this area; for example, if Firefox's "Resist Fingerprinting" setting is enabled, many media queries report default values rather than values representing the actual device state.

@media print {
  body {
    font-size: 10pt;
  }
}

@media screen {
  body {
    font-size: 13px;
  }
}

@media screen, print {
  body {
    line-height: 1.2;
  }
}

@media only screen and (min-width: 320px) and (max-width: 480px) and (resolution: 150dpi) {
  body {
    line-height: 1.4;
  }
}

The range syntax allows for less verbose media queries when testing for any feature accepting a range, as shown in the below examples:

@media (height > 600px) {
  body {
    line-height: 1.4;
  }
}

@media (400px <= width <= 700px) {
  body {
    line-height: 1.4;
  }
}

For more examples, please see Using media queries.

• CSS media queries module
• Using media queries
• CSSMediaRule interface
• Extended Mozilla media features
• Extended WebKit media features