What is css3 unit

In CSS3, the unit is a unit of measurement, which can be divided into two types: 1. Size unit, used to express length, including em, rem, vw, vh, % and other relative length units and px , cm, pc and other absolute length units; 2. Color units, used to represent colors, including color names (such as red), "rgb(x,x,x)" and so on.

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

In CSS3, a unit is a unit of measurement that can be divided into two types: size units and color units.

css size units:

There are many css size units, which can be described as diverse, but they can basically be divided into two categories: relative length units , absolute length unit.

Relative length units

Relative length units specify the properties of one length relative to another length. It is more suitable for different device relative lengths.

Unit	Description
em	It is the description relative to the current application The font size of the element, so it is also a relative length unit. The default font size of general browsers is 16px, then 2em == 32px;
ex	depends on the height of the English letter x
ch	The width of the number 0
#rem	rem is the abbreviation of root em (root em), rem acts on non-root When the element is used, it is relative to the font size of the root element; when rem acts on the font size of the root element, it is relative to its initial font size.
vw	viewpoint width, window width, 1vw=1% of the window width
vh	viewpoint height, window height, 1vh=1% of the window height
vmin	The smaller of vw and vh.
vmax	The larger of vw and vh.
%

Tip: What is the difference between rem and em? The difference is that when using rem to set the font size for an element, it is still a relative size, but it is only relative to the HTML root element.

Absolute length unit

The absolute length unit is a fixed value that reflects a real physical size. Absolute length units depend on the output medium and are independent of the environment (monitor, resolution, operating system, etc.).

Unit	Description
cm	cm
mm	MM
in	Inches (1in = 96px = 2.54cm)
px *	pixel (1px = 1/96th of 1in)
pt	point, approximately 1/72 inch; (1pt = 1/72in)
pc	pica, about 12pt, 1/6 inch; (1pc = 12 pt)

Pixels may be considered the best "device pixels", and this pixel length has nothing to do with the text screen pixels you see on your monitor. px is actually a unit measured in degrees.

Color unit:

##UnitDescription(color name)Color name(such as red)rgb(x,x,x)RGB value (such as rgb(255,0,0))rgb(x%, x%, x%)RGB percentage value (such as rgb( 100%,0%,0%))#rrggbbHexadecimal number (such as #ff0000) (Learning video sharing:

css video tutorial, web front-end)

The above is the detailed content of What is css3 unit. For more information, please follow other related articles on the PHP Chinese website!