解决font property font-family does not have generic default

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原因

编辑器检查 css 错误的时候，总是提示“font property font-family does not have generic default”，编辑器是根据W3C标准来提示的，原来是因为没有定义 “generic-family”即 字体的所属风格。
例如：serif，sans-serif，cursive。

解决

加上generic-family就好了，中文用serif 或 sans-serif。
示例

body{font-family:"宋体"，serif;}

W3C: Font family: the ‘font-family’ property

Name: font-family

Value: [family-name | generic-family ]， [ family-name| generic-family ]* ] | inherit
Initial: depends on user agent
Applies to: all elements
Inherited: yes
Percentages: N/A
Media: visual
Computed value: as specified
The property value is a prioritized list of font family names and/or generic family names. Unlike most other CSS properties, component values are separated by a comma to indicate that they are alternatives:

body { font-family: Gill, Helvetica, sans-serif }
Although many fonts provide the “missing character” glyph, typically an open box, as its name implies this should not be considered a match for characters that cannot be found in the font. (It should, however, be considered a match for U+FFFD, the “missing character” character’s code point).

There are two types of font family names:

The name of a font family of choice. In the last example, “Gill” and “Helvetica” are font families.

In the example above, the last value is a generic family name. The following generic families are defined:
‘serif’ (e.g., Times)
‘sans-serif’ (e.g., Helvetica)
‘cursive’ (e.g., Zapf-Chancery)
‘fantasy’ (e.g., Western)
‘monospace’ (e.g., Courier)
Style sheet designers are encouraged to offer a generic font family as a last alternative. Generic font family names are keywords and must NOT be quoted.

Font family names must either be given quoted as strings, or unquoted as a sequence of one or more identifiers. This means most punctuation characters and digits at the start of each token must be escaped in unquoted font family names.

For example, the following declarations are invalid:

font-family: Red/Black, sans-serif;
font-family: “Lucida” Grande, sans-serif;
font-family: Ahem!, sans-serif;
font-family: test@foo, sans-serif;
font-family: #POUND, sans-serif;
font-family: Hawaii 5-0, sans-serif;
If a sequence of identifiers is given as a font family name, the computed value is the name converted to a string by joining all the identifiers in the sequence by single spaces.

To avoid mistakes in escaping, it is recommended to quote font family names that contain white space, digits, or punctuation characters other than hyphens:

body { font-family: “New Century Schoolbook”, serif }

Unquoted font family names that happen to be the same as the keyword values ‘inherit’, ‘default’ and ‘initial’ or the generic font keywords (‘serif’, ‘sans-serif’, ‘monospace’, ‘fantasy’, and ‘cursive’) do not match the ‘’ type. These names must be quoted to prevent confusion with the keywords with the same names. Note that ‘font-family: Times, inherit’ is therefore an invalid declaration, because ‘inherit’ in that position can neither be a valid keyword nor a valid font family name.

Generic font families

Generic font families are a fallback mechanism, a means of preserving some of the style sheet author’s intent in the worst case when none of the specified fonts can be selected. For optimum typographic control, particular named fonts should be used in style sheets.

All five generic font families are defined to exist in all CSS implementations (they need not necessarily map to five distinct actual fonts). User agents should provide reasonable default choices for the generic font families, which express the characteristics of each family as well as possible within the limits allowed by the underlying technology.

User agents are encouraged to allow users to select alternative choices for the generic fonts.

serif

Glyphs of serif fonts, as the term is used in CSS, tend to have finishing strokes, flared or tapering ends, or have actual serifed endings (including slab serifs). Serif fonts are typically proportionately-spaced. They often display a greater variation between thick and thin strokes than fonts from the ‘sans-serif’ generic font family. CSS uses the term ‘serif’ to apply to a font for any script, although other names may be more familiar for particular scripts, such as Mincho (Japanese), Sung or Song (Chinese), Totum or Kodig (Korean). Any font that is so described may be used to represent the generic ‘serif’ family.

Examples of fonts that fit this description include:

Latin fonts Times New Roman, Bodoni, Garamond, Minion Web, ITC Stone Serif, MS Georgia, Bitstream Cyberbit
Greek fonts Bitstream Cyberbit
Cyrillic fonts Adobe Minion Cyrillic, Excelsior Cyrillic Upright, Monotype Albion 70, Bitstream Cyberbit, ER Bukinist
Hebrew fonts New Peninim, Raanana, Bitstream Cyberbit
Japanese fonts Ryumin Light-KL, Kyokasho ICA, Futo Min A101
Arabic fonts Bitstream Cyberbit
Cherokee fonts Lo Cicero Cherokee

sans-serif

Glyphs in sans-serif fonts, as the term is used in CSS, tend to have stroke endings that are plain – with little or no flaring, cross stroke, or other ornamentation. Sans-serif fonts are typically proportionately-spaced. They often have little variation between thick and thin strokes, compared to fonts from the ‘serif’ family. CSS uses the term ‘sans-serif’ to apply to a font for any script, although other names may be more familiar for particular scripts, such as Gothic (Japanese), Kai (Chinese), or Pathang (Korean). Any font that is so described may be used to represent the generic ‘sans-serif’ family.

Examples of fonts that fit this description include:

Latin fonts MS Trebuchet, ITC Avant Garde Gothic, MS Arial, MS Verdana, Univers, Futura, ITC Stone Sans, Gill Sans, Akzidenz Grotesk, Helvetica
Greek fonts Attika, Typiko New Era, MS Tahoma, Monotype Gill Sans 571, Helvetica Greek
Cyrillic fonts Helvetica Cyrillic, ER Univers, Lucida Sans Unicode, Bastion
Hebrew fonts Arial Hebrew, MS Tahoma
Japanese fonts Shin Go, Heisei Kaku Gothic W5
Arabic fonts MS Tahoma

cursive

Glyphs in cursive fonts, as the term is used in CSS, generally have either joining strokes or other cursive characteristics beyond those of italic typefaces. The glyphs are partially or completely connected, and the result looks more like handwritten pen or brush writing than printed letterwork. Fonts for some scripts, such as Arabic, are almost always cursive. CSS uses the term ‘cursive’ to apply to a font for any script, although other names such as Chancery, Brush, Swing and Script are also used in font names.

Examples of fonts that fit this description include:

Latin fonts Caflisch Script, Adobe Poetica, Sanvito, Ex Ponto, Snell Roundhand, Zapf-Chancery
Cyrillic fonts ER Architekt
Hebrew fonts Corsiva
Arabic fonts DecoType Naskh, Monotype Urdu 507

fantasy

Fantasy fonts, as used in CSS, are primarily decorative while still containing representations of characters (as opposed to Pi or Picture fonts, which do not represent characters). Examples include:

Latin fonts Alpha Geometrique, Critter, Cottonwood, FB Reactor, Studz

monospace

The sole criterion of a monospace font is that all glyphs have the same fixed width. (This can make some scripts, such as Arabic, look most peculiar.) The effect is similar to a manual typewriter, and is often used to set samples of computer code.

Examples of fonts which fit this description include:

Latin fonts Courier, MS Courier New, Prestige, Everson Mono
Greek Fonts MS Courier New, Everson Mono
Cyrillic fonts ER Kurier, Everson Mono
Japanese fonts Osaka Monospaced
Cherokee fonts Everson Mono

感觉对中文的意义不大，因为字体显示总归要来源当前系统所安装的字体。