sass基础语法
sass基础语法
!default 表示默认值
+ 拼接字符串
#{ } 识别为变量名
demo.scss
$width:300px; $height:300px; $color:#e03434; $baseWidth:200px; $baseWidth:100px !default; .div1{ width:$width; height:$height; background-color:$color; } .div2{ width:$baseWidth; height:$baseWidth; background-color:$color; }
demo.css
.div1 { width: 300px; height: 300px; background-color: #e03434; } .div2 { width: 200px; height: 200px; background-color: #e03434; }
变量作用域
内部变量只能在内部使用,否则会报错
demo.scss
$width: 300px; $color: #ffe932; .div1 { height: $width; $widthInner: 100px; width: $widthInner; } .div2 { width: $width; }
demo.css
.div1 { height: 300px; width: 100px; } .div2 { width: 300px; }
通常,@import
寻找 Sass 文件并将其导入,但在以下情况下,@import
仅作为普通的 CSS 语句,不会导入任何 Sass 文件。
- 文件拓展名是
.css
; - 文件名以
http://
开头; - 文件名是
url()
; @import
包含 media queries。
org.scss
@import ‘org.css‘;
org.css
@import url(org.css); /*# sourceMappingURL=org.css.map */
正常情况下的使用:
在_base.scss中写入通用样式
$color: red !default; body { margin: 0; padding: 0; }
引用通用样式文件
demo.scss
@import ‘base‘; $width: 300px; $color: #ffe932; .div { width: $width; background-color: $color; }
demo.css
body { margin: 0; padding: 0; } .div { width: 300px; background-color: #ffe932; }
sass常见的基本数据类型
list 数组下标从1开始
demo.scss
$width: 300px; $zoomValue: 2; $color: red; $colorHex: #ffe932; $str: ‘hello.jpeg‘; $list: (100px,200px,‘string‘,2); $map: (top:1px,left:2px,bottom:3px,right:4px); /*number*/ .div { width: $width; height: $width; zoom: $zoomValue; } /*color*/ .div { color: $color; background-color: $colorHex; } /*string*/ .div { background-image: url(‘images/‘+$str); } /*list*/ .div { width: nth($list, 1); height: nth($list, 2); zoom:index($list,‘string‘); } /*map*/ .div { top:map-get($map,top); left:map-get($map,left); } .div { @each $key, $value in $map { #{$key}:$value; } }
demo.css
/*number*/ .div { width: 300px; height: 300px; zoom: 2; } /*color*/ .div { color: red; background-color: #ffe932; } /*string*/ .div { background-image: url("images/hello.jpeg"); } /*list*/ .div { width: 100px; height: 200px; zoom: 3; } /*map*/ .div { top: 1px; left: 2px; } .div { top: 1px; left: 2px; bottom: 3px; right: 4px; }
sass加减乘除基本运算
直接运算需要加 ()
通过变量进行运算不需要加 ()
demo.scss
$num1:100px; $num2:200px; $width: $num1 + $num2; $color1: #010203; $color2: #040506; $color3: #a69e61; $str:‘hello.jpeg‘; .div { width: $width; } /* 加减乘除 */ .div { font: 10px/8px; font: (10px/8); font: (10px*8); width: $width/2; margin-left: (5px + 8px/2); } /*颜色运算*/ // 不建议直接运算 .div { color: $color1 + $color2; } // 建议使用sass内置函数 .div { color: mix($color1, $color2);//混合色 color: red($color1);//red 取出红色值 color: red($color3); color: green($color3); color: blue($color3); color: rgb(red($color3),green($color3),blue($color3));//拼接处想要的色值 } /*字符串*/ .div { background-image: url(‘images/‘+$str); }
demo.css
@charset "UTF-8"; .div { width: 300px; } /* 加减乘除 */ .div { font: 10px/8px; font: 1.25px; font: 80px; width: 150px; margin-left: 9px; } /*颜色运算*/ .div { color: #050709; } .div { color: #030405; color: 1; color: 166; color: 158; color: 97; color: #a69e61; } /*字符串*/ .div { background-image: url("images/hello.jpeg"); } /*# sourceMappingURL=demo.css.map */
mixin 语法块
demo.scss
/*一般mixin*/ @mixin helloMixin { display: inline-block; padding: 20px; font: { size: 20px; weight: 500; } color: red; } /*嵌套mixin*/ @mixin helloMixin2 { padding: 10px; @include helloMixin; background-color: red; } /*参数mixin*/ @mixin sexy-border($color, $width) { border: { color: $color; width: $width; style:dashed; }; } .div { width: 100px; @include helloMixin2; } .div { @include sexy-border(blue,2px); }
demo.css
@charset "UTF-8"; /*一般mixin*/ /*嵌套mixin*/ /*参数mixin*/ .div { width: 100px; padding: 10px; display: inline-block; padding: 20px; font-size: 20px; font-weight: 500; color: red; background-color: red; } .div { border-color: blue; border-width: 2px; border-style: dashed; }
sass继承和嵌套
demo.scss
/*简单继承*/ .div { border:1px; background-color: red; } .divext { @extend .div; border-width: 3px; } /*关联属性继承*/ .div1 { border:1px; background-color: red; } .div1.other { background-image: url(‘hello.jpeg‘); } .divext { @extend .div1; } /*链式继承*/ .div1 { border: 1px solid #000; color: blue; } .div2 { @extend .div1; color: red; } .div3 { @extend .div2; color: #000; } /*伪类继承*/ a:hover { text-decoration: underline; } .hoverlink { color: red; @extend :hover; }
demo.css
@charset "UTF-8"; /*简单继承*/ .div, .divext { border: 1px; background-color: red; } .divext { border-width: 3px; } /*关联属性继承*/ .div1, .divext, .div2, .div3 { border: 1px; background-color: red; } .div1.other, .other.divext, .other.div2, .other.div3 { background-image: url("hello.jpeg"); } /*链式继承*/ .div1, .divext, .div2, .div3 { border: 1px solid #000; color: blue; } .div2, .div3 { color: red; } .div3 { color: #000; } /*伪类继承*/ a:hover, a.hoverlink { text-decoration: underline; } .hoverlink { color: red; } /*# sourceMappingURL=demo.css.map */
嵌套--子元素的样式
嵌套--样式属性分离
demo.scss
$width: 300px; $color: #fff; .div1 { width: $width; height: $width;; background-color: #color; .div-inner { width: $width; height: $width; background-color: #color; .div-inner-inner { width: $width; height: $width; background-color: #color; } } a { color: red; } } .div1 { width: $width; height: $width;; background-color: #color; .div-inner { border: { left: 1px solid #000; top: 2px solid #000;; }; background: { image:url(‘abc.png‘); color: #000;; }; } }
demo.css
.div1 { width: 300px; height: 300px; background-color: #color; } .div1 .div-inner { width: 300px; height: 300px; background-color: #color; } .div1 .div-inner .div-inner-inner { width: 300px; height: 300px; background-color: #color; } .div1 a { color: red; } .div1 { width: 300px; height: 300px; background-color: #color; } .div1 .div-inner { border-left: 1px solid #000; border-top: 2px solid #000; background-image: url("abc.png"); background-color: #000; }
sass条件控制
demo.scss
/*if*/ $type: ‘bufy‘; p { @if $type == ‘bufy‘ { color: red; } @else if $type == ‘tim‘ { color: blue; } @else if $type == ‘tony‘ { color: green; } @else { color: black; } } @if $type == ‘bufy‘ { .div { color: red; } }@else { .div { color: blue; } } /*for*/ @for $i from 1 through 3 { .item#{$i} { width: 1px * $i; } } @for $i from 1 to 3 { .item#{$i} { width: 1px * $i; } } /*for list*/ $list:(1,2,3,4,5); @for $i from 1 through length($list) { .item#{$i} { width: 1px * $i; } } /*while*/ $i: 6; @while $i > 0 { .item#{$i} { width: 1px * $i; } $i: $i - 2; } /*each*/ $map:(top: 1px,left:2px,bottom: 3px,right: 4px); .div { @each $key , $value in $map { #{$key}:$value; } }
demo.css
/*if*/ p { color: red; } .div { color: red; } /*for*/ .item1 { width: 1px; } .item2 { width: 2px; } .item3 { width: 3px; } .item1 { width: 1px; } .item2 { width: 2px; } /*for list*/ .item1 { width: 1px; } .item2 { width: 2px; } .item3 { width: 3px; } .item4 { width: 4px; } .item5 { width: 5px; } /*while*/ .item6 { width: 6px; } .item4 { width: 4px; } .item2 { width: 2px; } /*each*/ .div { top: 1px; left: 2px; bottom: 3px; right: 4px; }
内置函数
@debug 实时打印结果
demo.scss
$number: 70; $number2: 71; $numberPercent: 0.77; $numberRound: 25.9; $abs: 3; /*number*/ .div { zoom:percentage($numberPercent); zoom:round($numberRound); zoom:ceil($numberRound); zoom:floor($numberRound); zoom:abs($abs); zoom:min($number,$number2); zoom:max($number,$number2); zoom: random(100); } /*list*/ $list:(1,‘p‘,3,4,5); .div { zoom: length($list);//获取数组长度 zoom: nth($list,2);//获取指定下标的元素 @debug set-nth($list, 1 ,‘x‘);//替换指定下标的元素 @debug join($list, (6,7,8));//拼接数组 @debug append($list,‘999‘);//从数组尾部添加元素 @debug index($list,‘p‘);//返回指定元素在数组中的位置 } /*string*/ $string:‘hello‘; $stringNo:hello; $stringUP: ‘HELLO‘; .div { background-image: unquote($string);//去除引号 background-image: quote($stringNo);//添加引号 background-image: str-length($string);//获取字符串长度 @debug str-insert($string,‘p‘,2);//在指定位置插入字符 @debug str-index($string,‘l‘);//返回指定字符在字符串中的位置 background-image: to-upper-case($string);//转大写 background-image: to-lower-case($stringUP);//转小写 } /*map*/ $map:(top: 1px,left:2px,bottom: 3px,right: 4px); .div { width: map-get($map,top);//根据key获取相关值 //map-merge($map1,$map2) //将两个map合并成一个新的map @debug map-remove($map,bottom);//从map中删除一个kep,返回一个新map @debug map-keys($map);//返回map中所有的key @debug map-values($map);//返回map中所有的value @debug map-has-key($map,abc);//判断map中是否有key对应的value值 } @mixin foo($args...) { @debug keywords($args); //返回一个函数的参数,这个参数可以动态的设置key和value } @include foo($arg1:‘abc‘,$arg2:‘efg‘); /*自定义函数*/ $rem1: 100px; @function px2rem($px) { $rem: 37.5px; @debug $px; @return ($px/$rem) + rem; }; .div { width: px2rem($rem1); }
demo.css
@charset "UTF-8"; /*number*/ .div { zoom: 77%; zoom: 26; zoom: 26; zoom: 25; zoom: 3; zoom: 70; zoom: 71; zoom: 28; } /*list*/ .div { zoom: 5; zoom: "p"; } /*string*/ .div { background-image: hello; background-image: "hello"; background-image: 5; background-image: "HELLO"; background-image: "hello"; } /*map*/ .div { width: 1px; } /*自定义函数*/ .div { width: 2.6666666667rem; } /*# sourceMappingURL=demo.css.map */
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