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What new units are added in css3

青灯夜游

Release： 2022-01-12 17:17:07

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New units added in css3: 1. "ch", the width of character 0; 2. "rem", a relative unit, mainly relative to the size of the root element font; 3. "vw", the window Width; 4. "vh", window height; 5. "vmin"; 6. "vmax", etc.

What new units are added in css3

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

New length units in CSS3

The new length units in CSS3 are as follows,

ch, the width of character 0
rem, is a relative unit, mainly relative to the size of the root element font, To use rem, we need to refer to the specified root element.
vw, viewpoint width, window width, 1vw=1% of the window width
vh, viewpoint height, window height, 1vh=1% of the window height
vmin, vmax, etc.

The newly added viewpoint-related units are generally targeted at mobile devices.

rem is actually the same thing as em, except that rem has an additional restriction, which represents the root element (html element) font-size. We can take a look at the difference between

rem and em through the following example,

<html style="font-size: 12px;">
<body>
    <div id="div1" style="font-size: 16px">
        <div id="div2" style="font-size: 1.2em"></div>
        <div id="div3" style="font-size: 1.2rem">
            <div id="div4" style="font-size: 1.2em"></div>
        </div>
    </div>
</body>
</html>

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At this time,

font-size of div2: 16px*1.2em=19.2px
##font-size of div3:
12px*1.2 rem=14.4px
font-size of div4:
12px*1.2rem*1.2em=17.28px

It can be seen that

rem does not have a cascading relationship, but em does.

It is worth noting that IE8 and below, Safari 4, IOS 3.2, etc. do not support

rem units.

(Learning video sharing:

css video tutorial)

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