@import
Baseline
Widely available
*
This feature is well established and works across many devices and browser versions. It’s been available across browsers since 2015年7月.
* Some parts of this feature may have varying levels of support.
概述
@import CSS @ 规则用于从其他样式表导入样式规则。这些规则必须先于所有其他类型的规则，@charset 规则除外；因为它不是一个嵌套语句，@import 不能在条件组的规则中使用。
因此，用户代理可以避免为不支持的媒体类型检索资源，作者可以指定依赖媒体的 @import 规则。这些条件导入在 URI 之后指定逗号分隔的媒体查询。在没有任何媒体查询的情况下，导入是无条件的。指定所有的媒体具有相同的效果。
语法
@import url; @import url list-of-media-queries;
其中：
正规语法
@import =
@import [ <url> | <string> ] [ layer | layer( <layer-name> ) ]? <import-conditions> ;
<layer-name> =
<ident> [ '.' <ident> ]*
<import-conditions> =
[ supports( [ <supports-condition> | <declaration> ] ) ]? <media-query-list>?
<supports-condition> =
not <supports-in-parens> |
<supports-in-parens> [ and <supports-in-parens> ]* |
<supports-in-parens> [ or <supports-in-parens> ]*
<supports-in-parens> =
( <supports-condition> ) |
<supports-feature> |
<general-enclosed>
<supports-feature> =
<supports-selector-fn> |
<supports-font-tech-fn> |
<supports-font-format-fn> |
<supports-at-rule-fn> |
<supports-decl>
<general-enclosed> =
[ <function-token> <any-value>? ) ] |
[ ( <any-value>? ) ]
<supports-selector-fn> =
selector( <complex-selector> )
<supports-font-tech-fn> =
font-tech( <font-tech> )
<supports-font-format-fn> =
font-format( <font-format> )
<supports-at-rule-fn> =
at-rule( <at-keyword-token> )
<supports-decl> =
( <declaration> )
<complex-selector> =
<complex-selector-unit> [ <combinator>? <complex-selector-unit> ]*
<font-tech> =
<font-features-tech> |
<color-font-tech> |
variations |
palettes |
incremental
<font-format> =
<string> |
collection |
embedded-opentype |
opentype |
svg |
truetype |
woff |
woff2
<complex-selector-unit> =
[ <compound-selector>? <pseudo-compound-selector>* ]!
<combinator> =
'>' |
'+' |
'~' |
[ '|' '|' ]
<font-features-tech> =
features-opentype |
features-aat |
features-graphite
<color-font-tech> =
color-COLRv0 |
color-COLRv1 |
color-SVG |
color-sbix |
color-CBDT
<compound-selector> =
[ <type-selector>? <subclass-selector>* ]!
<pseudo-compound-selector> =
<pseudo-element-selector> <pseudo-class-selector>*
<type-selector> =
<wq-name> |
<ns-prefix>? '*'
<subclass-selector> =
<id-selector> |
<class-selector> |
<attribute-selector> |
<pseudo-class-selector>
<pseudo-element-selector> =
: <pseudo-class-selector> |
<legacy-pseudo-element-selector>
<pseudo-class-selector> =
: <ident-token> |
: <function-token> <any-value> )
<wq-name> =
<ns-prefix>? <ident-token>
<ns-prefix> =
[ <ident-token> | '*' ]? '|'
<id-selector> =
<hash-token>
<class-selector> =
'.' <ident-token>
<attribute-selector> =
'[' <wq-name> ']' |
'[' <wq-name> <attr-matcher> [ <string-token> | <ident-token> ] <attr-modifier>? ']'
<legacy-pseudo-element-selector> =
: [ before | after | first-line | first-letter ]
<attr-matcher> =
[ '~' | '|' | '^' | '$' | '*' ]? '='
<attr-modifier> =
i |
s
示例
css
@import url("fineprint.css") print;
@import url("bluish.css") projection, tv;
@import "custom.css";
@import url("chrome://communicator/skin/");
@import "common.css" screen, projection;
@import url("landscape.css") screen and (orientation: landscape);
规范
| Specification |
|---|
| CSS Cascading and Inheritance Level 5 # at-import |
浏览器兼容性
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