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.

Media types describe the general category of a device. Except when using the not or only logical operators, 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.

Media features describe specific characteristics of the user agent, output device, or environment. Media feature expressions test for their presence or value, 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? Added in Media Queries Level 4.

any-pointer

Is any available input mechanism a pointing device, and if so, how accurate is it? Added in Media Queries Level 4.

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. Added in Media Queries Level 4.

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 Deprecated

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

device-height Deprecated

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

device-width Deprecated

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

display-mode

The display mode of the application, as specified in the web app manifest's display member. Defined in the Web App Manifest spec.

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? Added in Media Queries Level 4.

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 frame 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? Added in Media Queries Level 4.

overflow-inline

Can content that overflows the viewport along the inline axis be scrolled? Added in Media Queries Level 4.

pointer

Is the primary input mechanism a pointing device, and if so, how accurate is it? Added in Media Queries Level 4.

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-motion

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

resolution

Pixel density of the output device.

scripting

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

update

How frequently the output device can modify the appearance of content. Added in Media Queries Level 4.

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. If you use the not operator, you must also specify a media type.

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.

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 using Level 4 media queries to improve the user's experience. For example, prefers-reduced-motion to detect if the user has requested that the system minimize the amount of animation or motion it uses.

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

@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;
  }
}

Introduced in Media Queries Level 4 is a new range syntax that 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.

• Using media queries
• In JavaScript, @media can be accessed via the CSS object model interface CSSMediaRule.
• Extended Mozilla media features
• Extended WebKit media features