What is the grammatical composition of media queries in css3

The syntax of media query is "@media not|only mediatype and (expressions) {CSS code...;}"; media query can be composed of multiple media and can contain one or more expressions. The expression returns true or false depending on whether the condition is true.

The operating environment of this tutorial: Windows 7 system, CSS3&&HTML5 version, Dell G3 computer.

CSS3's multimedia queries inherit all the ideas of CSS2 multimedia types: instead of looking for device types, CSS3 displays adaptively according to settings.

Media queries can be used to detect many things, such as:

• The width and height of the viewport(window)

• The device Width and height

• Orientation (horizontal screen, vertical screen of smartphone)

• Resolution

Currently, many devices such as Apple phones, Android phones, tablets, etc. use multimedia queries.

Query syntax

@media not|only mediatype and (expressions) {
    CSS 代码...;
 }

Multimedia query consists of a variety of media and can contain one or more expressions. The expression is based on whether the condition is true. Returns true or false.

Media type

#If the specified multimedia type matches the device type, the query result returns true, and the document will be on the matching device Display the specified style effect.

Unless the not or only operators are used, all styles will adapt to display on all devices.

Value	Description
all	is used for All media devices
print	for printers
screen	for computer screens, tablets , smartphones, etc.
speech	for screen readers

Media Function

Value	Description
aspect- ratio	Define the ratio of the width and height of the visible area of ​​the page in the output device
color	Define the number of color originals in each set of the output device . If it is not a color device, the value is equal to 0
color-index	The number of entries defined in the output device's color lookup table. If no color lookup table is used, the value is equal to 0
device-aspect-ratio	Defines the ratio of the visible width to height of the screen of the output device.
device-height	Define the screen visible height of the output device.
device-width	Define the visible width of the screen of the output device.
height	Define the height of the visible area of ​​the page in the output device.
max-aspect-ratio	Defines the maximum ratio of the output device's screen visible width to height.
max-color	Define the maximum number of color originals in each group of output devices.
max-color-index	Defines the maximum number of entries in the output device's color lookup table.
max-device-aspect-ratio	Defines the maximum ratio of the output device's screen visible width to height.
max-device-height	Defines the maximum height visible on the screen of the output device.
max-device-width	Define the maximum visible width of the screen of the output device.
max-height	Define the maximum visible area height of the page in the output device.
max-resolution	Define the maximum resolution of the device.
max-width	Define the maximum visible area width of the page in the output device.
min-device-width	Define the minimum visible width of the screen of the output device.
min-device-height	Defines the minimum visible height of the screen of the output device.
min-height	Define the minimum visible area height of the page in the output device.
min-width	Define the minimum visible area width of the page in the output device.
orientation	Defines whether the height of the visible area of ​​the page in the output device is greater than or equal to the width.
resolution	Define the resolution of the device. For example: 96dpi, 300dpi, 118dpcm
width	Define the width of the visible area of ​​the page in the output device.

For example
The screen width is greater than 480px, and the font size is set to 16px.

@media screen and (min-width: 480px) {
    body {
       font-size:16px;
    }
}

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