@mixin GOD($SHOW:true) {
  @if $SHOW {
      display: block;
    }
    @else {
      display: none;
    }
}

.block {
  @include GOD;
}

.hidden{
  @include GOD(false);
}

@for $i from 1 through 5 { //生成到col-5
  .col-#{$i} { width: 2rem * $i; }
}

@for $i from 1 to 5 { //生成到col-4
  .col-#{$i} { width: 2rem * $i; }
}

$number: 5;
$number-width: 20px;

@while $number > 0 {
    .col-#{$number} {
        width: $mumber-width * $number;
    }
    $number: $number - 1;
}

$list: adam john wynn mason kuroir;//$list 就是一个列表

@mixin author-images {
    @each $author in $list {
        .photo-#{$author} {
            background: url("/images/avatars/#{$author}.png") no-repeat;
        }
    }
}

.author-bio {
    @include author-images;
}

@import "foo.css";
@import "foo" screen;
@import "http://foo.com/bar";
@import url(foo);

.test1 {
    content:  unquote('Hello Sass!') ;//结果->content: Hello Sass!;
}
.test2 {
    content: quote(Hello Sass!);//结果->content: "Hello Sass!";
}
.test3 {
    content: to-upper-case("Hello Sass!");//结果->content: "HELLO SASS!" ;
}
.test4 {
    content:  to-lower-case("'Hello Sass!'");//结果->content: "hello sass!";
}

.div1{
    width : percentage(5px / 10px) //20%
}
.div2{
    width : round(5.4px) //5px
}
.div3{
    width : ceil(7.1px) //8px
}
.div4{
    width : floor(9.9px) //9px
}
.div5{
    width : abs(-10px) //10px
}
.div6{
    width : min(5px ,10px) //5px
}
.div7{
    width : max(5px , 10px) //10px
}
.div8{
    width : random()px //鬼才知道的随机数
}

length(10px) //1
length(10px 20px (border 1px solid) 2em) //4
length(border 1px solid) //3

nth(10px 20px 30px,1) //10px
nth((Helvetica,Arial,sans-serif),2) //"Arial"
nth((1px solid red) border-top green,1) //(1px "solid" #ff0000)

join(10px 20px, 30px 40px) //(10px 20px 30px 40px)
join((blue,red),(#abc,#def)) //(#0000ff, #ff0000, #aabbcc, #ddeeff)
join((blue red), join((#abc #def),(#dee #eff))) //(#0000ff #ff0000 #aabbcc #ddeeff #ddeeee #eeffff)

append(10px 20px ,30px) //(10px 20px 30px)

zip(1px 2px 3px,solid dashed dotted,green blue red) //((1px "solid" #008000), (2px "dashed" #0000ff), (3px "dotted" #ff0000))

index(1px solid red, solid) //2

type-of(100) //"number"
type-of(100px) //"number"
type-of("asdf") //"string"
type-of(asdf) //"string"
type-of(true) //"bool"
type-of(#fff) //"color"

unit(100) //""
unit(100px) //"px"
unit(20%) //"%"
unit(10px * 3em) //"em*px"
unit(10px * 2em / 3cm / 1rem) //"em/rem"

unitless(100) //true
unitless(100px) //false
unitless(100em) //false
unitless(1 /2 + 2 ) //true
unitless(1px /2 + 2 ) //false

comparable(2px,1%) //false
comparable(2px,1em) //false
comparable(2px,1cm) //true

{
"employees": [
{ "firstName":"John" , "lastName":"Doe" },
{ "firstName":"Anna" , "lastName":"Smith" },
{ "firstName":"Peter" , "lastName":"Jones" }
]
}

hsl(200,30%,60%) //通过h200,s30%，l60%创建一个颜色 #7aa3b8
hsla(200,30%,60%,.8)//通过h200,s30%，l60%,a80%创建一个颜色 rgba(122, 163, 184, 0.8)
hue(#7ab)//得到#7ab颜色的色相值 195deg
saturation(#7ab)//得到#7ab颜色的饱和度值 33.33333%
lightness(#7ab)//得到#7ab颜色的亮度值 60%
adjust-hue(#f36,150deg) //改变#f36颜色的色相值为150deg #33ff66
lighten(#f36,50%) //把#f36颜色亮度提高50% #ffffff
darken(#f36,50%) //把#f36颜色亮度降低50% #33000d
saturate(#f36,50%) //把#f36颜色饱和度提高50% #ff3366
desaturate(#f36,50%) //把#f36颜色饱和度降低50% #cc667f
grayscale(#f36) //把#f36颜色变成灰色 #999999
complement(#f36) //#33ffcc
invert(#f36) //#00cc99

$oneWidth: 10px;  
$twoWidth: 40px;  
  
@function widthFn($n) {  
  @return $n * $twoWidth + ($n - 1) * $oneWidth;  
}  
  
.leng {   
    width: widthFn(5);  
}