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