📅 最后修改于: 2020-10-26 04:41:37 🧑 作者: Mango
在开始实际练习之前，我们想简要介绍一下CSS度量单位。 CSS支持多种度量，包括诸如英寸，厘米，点等的绝对单位，以及诸如百分比和em单位的相对度量。在样式规则中指定各种度量时，您需要这些值，例如border =“ 1px solid red” 。
我们列出了所有CSS度量单位以及正确的示例-
| Unit | Description | Example |
|---|---|---|
| % | Defines a measurement as a percentage relative to another value, typically an enclosing element. | p {font-size: 16pt; line-height: 125%;} |
| cm | Defines a measurement in centimeters. | div {margin-bottom: 2cm;} |
| em | A relative measurement for the height of a font in em spaces. Because an em unit is equivalent to the size of a given font, if you assign a font to 12pt, each “em” unit would be 12pt; thus, 2em would be 24pt. | p {letter-spacing: 7em;} |
| ex | This value defines a measurement relative to a font’s x-height. The x-height is determined by the height of the font’s lowercase letter x. | p {font-size: 24pt; line-height: 3ex;} |
| in | Defines a measurement in inches. | p {word-spacing: .15in;} |
| mm | Defines a measurement in millimeters. | p {word-spacing: 15mm;} |
| pc | Defines a measurement in picas. A pica is equivalent to 12 points; thus, there are 6 picas per inch. | p {font-size: 20pc;} |
| pt | Defines a measurement in points. A point is defined as 1/72nd of an inch. | body {font-size: 18pt;} |
| px | Defines a measurement in screen pixels. | p {padding: 25px;} |