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CSS Reference Manual

CSS Reference Manual CSS Selector CSS Voice Reference CSS Web Secure Font CSS Animation CSS unit CSS Colour CSS Legal color values CSS The color name CSS Color Hexadecimal value CSS Browser support

CSS Attributes

align-content align-items align-self all animation animation-delay animation-direction animation-duration animation-fill-mode animation-iteration-count animation-name animation-play-state animation-timing-function appearance backface-visibility background background-attachment background-blend-mode background-clip background-color background-image background-origin background-position background-repeat background-size border border-bottom border-bottom-color border-bottom-left-radius border-bottom-right-radius border-bottom-style border-bottom-width border-collapse border-color border-image border-image-outset border-image-repeat border-image-slice border-image-source border-image-width border-left border-left-color border-left-style border-left-width border-radius border-right border-right-color border-right-style border-right-width border-spacing border-style border-top border-top-color border-top-left-radius border-top-right-radius border-top-style border-top-width border-width bottom box-align box-direction box-flex box-flex-group box-lines box-ordinal-group box-orient box-pack box-shadow box-sizing caption-side clear clip color column-count column-fill column-gap column-rule column-rule-color column-rule-style column-rule-width column-span column-width columns content counter-increment counter-reset cursor direction display empty-cells filter flex flex-basis flex-direction flex-flow flex-grow flex-shrink flex-wrap float font @font-face font-family font-size font-size-adjust font-stretch font-style font-variant font-weight grid-columns grid-rows hanging-punctuation height icon justify-content @keyframes left letter-spacing line-height list-style list-style-image list-style-position list-style-type margin margin-bottom margin-left margin-right margin-top max-height max-width @media min-height min-width nav-down nav-index nav-left nav-right nav-up opacity order outline outline-color outline-offset outline-style outline-width overflow overflow-x overflow-y padding padding-bottom padding-left padding-right padding-top page-break-after page-break-before page-break-inside perspective perspective-origin position punctuation-trim quotes resize right rotation tab-size table-layout target target-name target-new target-position text-align text-align-last text-decoration text-decoration-color text-decoration-line text-decoration-style text-indent text-justify text-outline text-overflow text-shadow text-transform text-wrap top transform transform-origin transform-style transition transition-delay transition-duration transition-property transition-timing-function unicode-bidi vertical-align visibility white-space width word-break word-spacing word-wrap z-index

CSS unit

CSS has several different units used to represent the length.

Some properties are set CSS length width, margin, padding, font-size, border-width, and so on.

Length and a digital units such as 10px, 2em, and so on.

Can not have spaces between numbers and units. If the length is 0, the unit can be omitted.

For some CSS properties, length can be negative.

There are two types of length units: relative and absolute.

Browser Support

The following table indicate the minimum browser versions that support units of length.

Unit of length
em, ex,%, px, cm, mm, in, pt, pc 1.0 3.0 1.0 1.0 3.5
ch 27.0 9.0 1.0 7.0 20.0
rem 4.0 9.0 3.6 4.1 11.6
vh, vw 20.0 9.0 19.0 6.0 20.0
vmin 20.0 9.0 * 19.0 6.0 20.0
vmax 26.0 not support 19.0 not support 20.0

Note: Internet Explorer 9 by non-standard name vm support vmin.

Relative length

Relative length units specify a length relative to the length of the property of another. Depending on the device the relative lengths more suitable.

unit description Online examples
em It is described with respect to the application of the font size of the current element, it is also relative length units. Usually the browser default font size is 16px, then 2em == 32px; try it
ex English picture depends on the height of the small x try it
ch The width of the number 0
rem Root element (html) The font-size
vw viewpoint width, the width of the window, 1vw = 1% of the width of the window try it
vh viewpoint height, window height, 1vh = window height of 1% try it
vmin vw and vh smaller one. try it
vmax vw and vh larger one. try it

NoteTip: rem em and what difference does it?Except that the element rem set the font size is still relatively size, but just the opposite HTML root element.

Absolute length

Absolute length unit is a fixed value, it reflects a real physical size. Absolute length units are highly dependent on the output medium, it does not depend on the environment (monitor, resolution, operating system, etc.).

unit description Online examples
cm cm try it
mm Millimeter try it
in Inch (1in = 96px = 2.54cm) try it
px * Pixel (1px = 1 / 96th of 1in) try it
pt point, about 1/72 of an inch; (1pt = 1 / 72in) try it
pc pica, about 6pt, 1/6 Yingcun; (1pc = 12 pt) try it

Perhaps the pixel is considered to be the best "device pixels" and this pixel length and you see the text on the display screen pixels irrelevant. px is actually a measure of an angle unit.