css单位pr,em,与颜色

HTML仅识别CSS1中的16个基本颜色关键字，使用特定算法转换未识别的值（通常为完全不同的颜色）。其他颜色关键字应仅用于CSS和SVG。与HTML不同，CSS将完全忽略未知关键字。颜色关键字全部代表纯色，纯色，没有透明度。CSS Level 1仅包含16种基本颜色，称为VGA颜色，因为它们是从VGA显卡上的可显示颜色集中获取的。CSS Level 2添加了orange关键字。尽管早期的浏览器支持不符合规范的各种颜色（大多数都是从X11颜色列表中改编而来），但直到SVG 1.0和CSS Colors Level 3才正式定义它们。它们被称为扩展颜色关键字，X11颜色或SVG颜色。CSS Colors Level 4添加了rebeccapurple关键字以表彰web先锋Eric Meyer。

颜色太多不好打字网站为：https://devdocs.io/css/color_value；颜色代码。

em：字体为斜体可以直接在HTML中使用。

pr：规则的prefix描述符@counter-style指定将被添加到标记表示的内容。如果未指定，则默认值为""（空字符串）。

`black`	`#000000`
	`silver`	`#c0c0c0`
	`gray`	`#808080`
	`white`	`#ffffff`
	`maroon`	`#800000`
	`red`	`#ff0000`
	`purple`	`#800080`
	`fuchsia`	`#ff00ff`
	`green`	`#008000`
	`lime`	`#00ff00`
	`olive`	`#808000`
	`yellow`	`#ffff00`
	`navy`	`#000080`
	`blue`	`#0000ff`
	`teal`	`#008080`
	`aqua`	`#00ffff`
CSS Level 2（修订版1）		`orange`	`#ffa500`
CSS颜色模块3级		`aliceblue`	`#f0f8ff`
		`antiquewhite`	`#faebd7`
		`aquamarine`	`#7fffd4`
		`azure`	`#f0ffff`
		`beige`	`#f5f5dc`
		`bisque`	`#ffe4c4`
		`blanchedalmond`	`#ffebcd`
		`blueviolet`	`#8a2be2`
		`brown`	`#a52a2a`
		`burlywood`	`#deb887`
		`cadetblue`	`#5f9ea0`
		`chartreuse`	`#7fff00`
		`chocolate`	`#d2691e`
		`coral`	`#ff7f50`
		`cornflowerblue`	`#6495ed`
		`cornsilk`	`#fff8dc`
		`crimson`	`#dc143c`
		`cyan` （同义词`aqua`）	`#00ffff`
		`darkblue`	`#00008b`
		`darkcyan`	`#008b8b`
		`darkgoldenrod`	`#b8860b`
		`darkgray`	`#a9a9a9`
		`darkgreen`	`#006400`
		`darkgrey`	`#a9a9a9`
		`darkkhaki`	`#bdb76b`
		`darkmagenta`	`#8b008b`
		`darkolivegreen`	`#556b2f`
		`darkorange`	`#ff8c00`
		`darkorchid`	`#9932cc`
		`darkred`	`#8b0000`
		`darksalmon`	`#e9967a`
		`darkseagreen`	`#8fbc8f`
		`darkslateblue`	`#483d8b`
		`darkslategray`	`#2f4f4f`
		`darkslategrey`	`#2f4f4f`
		`darkturquoise`	`#00ced1`
		`darkviolet`	`#9400d3`
		`deeppink`	`#ff1493`
		`deepskyblue`	`#00bfff`
		`dimgray`	`#696969`
		`dimgrey`	`#696969`
		`dodgerblue`	`#1e90ff`
		`firebrick`	`#b22222`
		`floralwhite`	`#fffaf0`
		`forestgreen`	`#228b22`
		`gainsboro`	`#dcdcdc`
		`ghostwhite`	`#f8f8ff`
		`gold`	`#ffd700`
		`goldenrod`	`#daa520`
		`greenyellow`	`#adff2f`
		`grey`	`#808080`
		`honeydew`	`#f0fff0`
		`hotpink`	`#ff69b4`
		`indianred`	`#cd5c5c`
		`indigo`	`#4b0082`
		`ivory`	`#fffff0`
		`khaki`	`#f0e68c`
		`lavender`	`#e6e6fa`
		`lavenderblush`	`#fff0f5`
		`lawngreen`	`#7cfc00`
		`lemonchiffon`	`#fffacd`
		`lightblue`	`#add8e6`
		`lightcoral`	`#f08080`
		`lightcyan`	`#e0ffff`
	`lightgoldenrodyellow`	`#fafad2`
	`lightgray`	`#d3d3d3`
	`lightgreen`	`#90ee90`
	`lightgrey`	`#d3d3d3`
	`lightpink`	`#ffb6c1`
	`lightsalmon`	`#ffa07a`
	`lightseagreen`	`#20b2aa`
	`lightskyblue`	`#87cefa`
	`lightslategray`	`#778899`
	`lightslategrey`	`#778899`
	`lightsteelblue`	`#b0c4de`
	`lightyellow`	`#ffffe0`
	`limegreen`	`#32cd32`
	`linen`	`#faf0e6`
	`magenta` （同义词`fuchsia`）	`#ff00ff`
	`mediumaquamarine`	`#66cdaa`
	`mediumblue`	`#0000cd`
	`mediumorchid`	`#ba55d3`
	`mediumpurple`	`#9370db`
	`mediumseagreen`	`#3cb371`
	`mediumslateblue`	`#7b68ee`
	`mediumspringgreen`	`#00fa9a`
	`mediumturquoise`	`#48d1cc`
	`mediumvioletred`	`#c71585`
	`midnightblue`	`#191970`
	`mintcream`	`#f5fffa`
	`mistyrose`	`#ffe4e1`
	`moccasin`	`#ffe4b5`
	`navajowhite`	`#ffdead`
	`oldlace`	`#fdf5e6`
	`olivedrab`	`#6b8e23`
	`orangered`	`#ff4500`
	`orchid`	`#da70d6`
	`palegoldenrod`	`#eee8aa`
	`palegreen`	`#98fb98`
	`paleturquoise`	`#afeeee`
	`palevioletred`	`#db7093`
	`papayawhip`	`#ffefd5`
	`peachpuff`	`#ffdab9`
	`peru`	`#cd853f`
	`pink`	`#ffc0cb`
	`plum`	`#dda0dd`
	`powderblue`	`#b0e0e6`
	`rosybrown`	`#bc8f8f`
	`royalblue`	`#4169e1`
	`saddlebrown`	`#8b4513`
	`salmon`	`#fa8072`
	`sandybrown`	`#f4a460`
	`seagreen`	`#2e8b57`
	`seashell`	`#fff5ee`
	`sienna`	`#a0522d`
	`skyblue`	`#87ceeb`
	`slateblue`	`#6a5acd`
	`slategray`	`#708090`
	`slategrey`	`#708090`
	`snow`	`#fffafa`
	`springgreen`	`#00ff7f`
	`steelblue`	`#4682b4`
	`tan`	`#d2b48c`
	`thistle`	`#d8bfd8`
	`tomato`	`#ff6347`
	`turquoise`	`#40e0d0`
	`violet`	`#ee82ee`
	`wheat`	`#f5deb3`
	`whitesmoke`	`#f5f5f5`
	`yellowgreen`	`#9acd32`
CSS颜色模块等级4		`rebeccapurple`	`#663399`

css单位pr,em,与颜色

transparent 关键词

`transparent` 关键词