@media

概要

@media CSS at-rule 與一組被大括弧隔開、並由 media query 條件定義的 CSS 巢狀區塊有關。@media at-rule 不只能用在最頂層的 CSS 區塊,也能在任何 CSS conditional-group at-rule 使用。

@media at-rule 能透過 CSS object model 介面 CSSMediaRule (en-US) 通行。

語法

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A <media-query> is composed of a optional media type and/or a number of media features.

Media types

all
Suitable for all devices.
print
Intended for paged material and for documents viewed on screen in print preview mode. Please consult the section on paged media, and the media section of the Getting Started tutorial for information about formatting issues that are specific to paged media.
screen
Intended primarily for color computer screens.
speech
Intended for speech synthesizers. Note: CSS2 had a similar media type called 'aural' for this purpose. See the appendix on aural style sheets for details.
Note: CSS2.1 and Media Queries 3 defined several additional media types (tty, tv, projection, handheld, braille, embossed, aural), but they were deprecated in Media Queries 4 and shouldn't be used.

Media Features

Each media feature tests for one specific feature of the browser or device.

Name Summary Notes
width Viewport width
height Viewport height
aspect-ratio Width-to-height aspect ratio of the viewport
orientation Orientation of the viewport
resolution Pixel density of the output device
scan Scanning process of the output device
grid Is the device a grid or bitmap?
update-frequency How quickly (if at all) can the output device modify the appearance of the content Added in Media Queries Level 4
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
color Number of bits per color component of the output device, or zero if the device isn't color.
color-index Number of entries in the output device's color lookup table, or zero if the device does not use such a table.
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.
monochrome Bits per pixel in the output device's monochrome frame buffer, or 0 if the device is not monochrome.
inverted-colors Is the user agent or underlying OS inverting colors? 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
hover Does the primary 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
any-hover Does any available input mechanism allow the user to hover over elements? Added in Media Queries Level 4
light-level Current ambient light level Added in Media Queries Level 4
scripting Is scripting (e.g. JavaScript) available? Added in Media Queries Level 4
device-width This is an obsolete API and is no longer guaranteed to work. Width of the rendering surface of the output device Deprecated in Media Queries Level 4
device-height This is an obsolete API and is no longer guaranteed to work. Height of the rendering surface of the output device Deprecated in Media Queries Level 4
device-aspect-ratio This is an obsolete API and is no longer guaranteed to work. Width-to-height aspect ratio of the output device Deprecated in Media Queries Level 4
-webkit-device-pixel-ratio Non-Standard Number of physical device pixels per CSS pixel Nonstandard; WebKit/Blink-specific. If possible, use the resolution media feature instead.
-webkit-transform-3d Non-Standard Are CSS 3D transforms supported? Nonstandard; WebKit/Blink-specific
-webkit-transform-2d Non-Standard Are CSS 2D transforms supported? Nonstandard; WebKit-specific
-webkit-transition Non-Standard Are CSS transitions supported? Nonstandard; WebKit-specific
-webkit-animation Non-Standard Are CSS animation (en-US)s supported? Nonstandard; WebKit-specific

Examples

@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-device-width: 320px)
  and (max-device-width: 480px)
  and (-webkit-min-device-pixel-ratio: 2) {
    body { line-height: 1.4 }
}

Specifications

Specification
Media Queries Level 4
# media-descriptor-table
CSS Conditional Rules Module Level 3
# at-media

Browser compatibility

BCD tables only load in the browser

See also