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Getting Started with Sass and Compass_html/css_WEB-ITnose
- WBOYOriginal
- 2016-06-24 11:46:111098browse
1./*Background knowledge*/
1. What is Sass?
Sass can simplify your CSS workflow and make it easier to extend and maintain your CSS! For example, there was a time when you had to constantly change a pixel value through find and replace because the customer's needs changed. Or, in order to determine the width of a column in a multi-column layout, you needed to use software to calculate the pixel value. Done.
Sass introduces some new concepts such as, variables, mixins, nesting and selector inheritance . Sass generates well-formatted CSS code that is easy to organize and maintain.
SASS is an expansion of the syntax of CSS3 (Cascading Style Sheet). It can use functions such as nesting, mix-in, selector inheritance, etc., and can write Stylesheet more efficiently and flexibly.
Sass will eventually compile legal CSS so that it can be used by browsers, which means that its own syntax is not easy for browsers to recognize (although it is very similar to the syntax of CSS, almost Same), because it is not a standard CSS format, you can use dynamic variables, etc. inside its syntax, so it is more like an extremely simple dynamic language.
2. What is Compass?
Compass was created by Chris Eppstein, a core team member of SASS. It is a very rich style framework, including A large number of well-defined mixins, functions, and extensions to SASS.
2./*Sass and Compass installation*/
// SASS is written in Ruby language, but the syntax of the two has nothing to do with it. If you don’t understand Ruby, you can still use it. It’s just thatRuby must be installed first, and then SASS.
// Assume you have installed Ruby, then enter the following command on the command line:
1 1.gem安装Sass 2 C:\Users\DELL>gem install sass 3 4 2.查看Sass版本 5 C:\Users\DELL>sass -v 6 Sass 3.4.13 (Selective Steve) 7 8 3.编译Sass文件 9 sass main.scss main css10 // 一般很少使用sass命令,一般都是用Compass命令;11 12 4.gem安装Compass13 C:\Users\DELL>gem install compass14 15 5.查看Compass版本16 C:\Users\DELL>compass -v17 Compass 1.0.3 (Polaris)
1 6.Compass搭建项目 2 C:\Users\DELL\compass create sass 3 // 结果:↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓ 5 directory sass/ 6 directory sass/sass/ // sass文件所在目录; 7 directory sass/stylesheets/ // css文件所在目录; 8 create sass/config.rb // 项目配置文件; 9 create sass/sass/screen.scss // 主要针对屏幕的sass文件;10 create sass/sass/print.scss // 主要针对打印设备;11 create sass/sass/ie.scss // 主要针对IE浏览器;12 write sass/stylesheets/ie.css13 write sass/stylesheets/print.css14 write sass/stylesheets/screen.css // scss文件编译后对应的css文件;最终将引入到HTML中的文件;15 16 // You may now add and edit sass stylesheets in the sass subdirectory of your project.17 // 你现在可以在sass文件的子文件中(screen.scss/print.scss/ie.scss)添加和编辑项目的样式表;18 19 // Sass files beginning with an underscore are called partials and won't be compiled to CSS, but they can be imported into other sass stylesheets.20 //<strong> Sass文件以"_"开头的叫做局部文件</strong>,<strong>不会被编译成CSS;但它们可以被引入到其他Sass文件中;</strong>21 22 // You can configure your project by editing the config.rb configuration file.23 // 你可以通过编辑config.rb配置文件来配置项目信息; 24 25 // You must compile your sass stylesheets into CSS when they change.26 //<strong> 当Sass文件被修改后,必须要编译Sass文件到CSS;</strong>27 28 // 1. To compile on demand: // 直接编译; 29 //<strong> compass compile</strong> [path/to/project]30 // 2. To monitor your project for changes and automatically recompile: 31 //<strong> compass watch</strong> [path/to/project] // 监听项目变化并且自动编译; 32 33 // To import your new stylesheets add the following lines of HTML (or equivalent) to your webpage:34 // <head>35 // <link href="/stylesheets/screen.css" media="screen, projection" rel="stylesheet" type="text/css" />36 // <link href="/stylesheets/print.css" media="print" rel="stylesheet" type="text/css" />37 // <!--[if IE]>38 // <link href="/stylesheets/ie.css" media="screen, projection" rel="stylesheet" type="text/css" />39 // <![endif]-->40 // </head>41 //<strong> 将编译后的文件引入到HTML页面中;</strong>
Three./*Sass syntax basics*/
1 1.scss和sass文件转换 2 sass-convert main.scss main.sass 3 // 将scss文件转换为sass文件; 4 5 2.开启监听编译 6 C:\Users\DELL>cd sass 7 // 进入项目文件夹; 8 C:\Users\DELL\sass><strong>compass watch </strong> 9 >>> Compass is watching for changes. Press Ctrl-C to Stop.10 // 开启监听并自动编译;11 12 3.变量13 //<strong> Sass通过"$"声明变量;</strong>14 >1.声明变量15 $headline-ff:"宋体",Arial,sans-serif;16 $main-sec-ff:Arial,sans-serif;17 >2.引用变量18 .headline {19 font-family:<strong> $headline-ff; </strong>20 }21 .main-sec {22 font-family: <strong>$main-sec-ff; </strong>23 }24 25 4.@import引入文件26 >1.新建局部文件27 _variables.scss28 //<strong> 以"_"开头的局部文件,不会被编译到css;作为引入文件使用;</strong>29 >2.@import引入文件30 @improt "variables";31 // 基于Sass的既定规则:32 //<strong> 1.没有文件后缀名的时候,sass会添加.scss或.sass的后缀;</strong>33 //<strong> 2.用同一目录下,局部文件和非局部文件不能重名;</strong>34 >3.使用css原生@import的既定规则:35 >>1.当@import后边跟的文件名是以".css"结尾的时候;36 >>2.当@import后边跟的是"http://"开头的字符串的时候;37 >>3.当@import后边跟的是一个url()函数的时候38 >>4.当@import后边带有media queries的时候;39 40 5.注释41 >1.以"/**/"注释的内容最后被输出到了对应的css文件中;42 >2.以"//"注释的内容则没有输出到对应的css文件;43 44 6.<strong>类嵌套语法 </strong>45 .main-sec{46 font-family: $main-sec-ff;47 .headline {48 font-family: $main-sec-ff;49 }50 }51 52 7.<strong>属性嵌套语法 </strong>53 .headline {54 font:{55 family:$main-sec-ff;56 size:16px;57 }58 }59 60 8.<strong>父类选择器(自身调用) </strong>61 a {62 &:hover {63 color:red;64 }65 } Four./*Sass syntax advanced*/
1 1.变量操作 2 >1.直接操作变量,即变量表达式; 3 >2.通过函数; 4 >>1.<strong>跟代码块无关的函数,多是自己内置函数,称为functions; </strong> 5 >>2.可重用的代码块:<strong>称为mixin; </strong> 6 >>>1.@include; //<strong> 以复制/拷贝的方式存在;</strong> 7 >>>2.@extend; //<strong> 以组合声明的方式存在;</strong> 8 9 2.颜色值转换;10 Sass:11 color:hsl(270,100%,50%);12 Css:13 color:#7f00ff;14 15 3.@mixin引用16 Sass:17 @mixin col-6 { //<strong> 声明col-6()函数;</strong>18 width:50%;19 float:left;20 }21 .webdemo-sec {22 <strong>@include col-6 // 通过@include引入@col-6()函数;并且可以引入多个;</strong>23 &:hover { // &:表示父类选择器;24 background-color:#f5f5f5;25 }26 }27 Css:28 .webdemo-sec { <strong> // 继承了col-6()函数的属性值;</strong>29 width:50%;30 float:left;31 }32 .webdemo-sec:hover { // 通过"&"调用到本身;33 background-color:#f5f5f5;34 }35 36 4.<strong>@mixin包含参数引用; </strong>37 Sass:38 <strong>@mixin col($width:50%){ // 设置默认参数值;不传参数时,属性值为默认;</strong>39 width:$width;40 float:right;41 }42 .webdemo-abc {43 @include col(60%); <strong>// 设置传参数;</strong>44 }45 Css:46 .webdemo-abc {47 width:60%; <strong>// 编译后的属性值;</strong>48 float:right;49 }50 51 5.@extend继承52 >1.extend不可以继承选择器序列;53 >2.<strong>使用</strong>%<strong>,用来构建只用来继承的选择器; </strong>54 Sass:55 .error {56 color:#f00;57 }58 <strong> %error { // 构建只用来要继承的选择器;</strong>59 background:#0f0;60 }61 .serious-error {62 @extend .error;63 @extend %error;64 border:1px solid #f00;65 }66 Css:67 .error, .serious-error { // 继承自.error;68 color:#f00;69 }70 .serious-error { // 继承自%serious-error;71 background:#0f0;72 }73 .serious-error { // 自己的属性;74 border:1px solid #f00;75 } 5./*Sass advanced syntax*/
1 2 1.@media用法 3 // Sass中的@media与Css中的@media区别: 4 // 1.<strong>Sass中的media query可以内嵌在css规则中;</strong> 5 // 2.<strong>在生成css的时候,media query才会被提到样式的最高级;</strong> 6 // 3.好处:避免了重复书写选择器或者打乱样式表的流程; 7 Sass: 8 @mixin col-sm ($width:50%){ 9 @media (min-width:768px){10 width:$width;11 float:left;12 }13 }14 .webdemo-sec {15 @include col-sm();16 }17 Css:18 <strong>@media (min-width:768px){ 19 .webdemo-sec { 20 width:50%; 21 float:left; 22 } 23 } </strong>24 25 2.@at-root指令26 //<strong> 嵌套副作用:增加了样式修饰的权重;制造了样式位置的依赖;</strong>27 Sass:28 .main-sec {29 font-size:12px;30 @at-root { //<strong> 在嵌套的时候使用@at-root指令;</strong>31 .main-sec-headline { //<strong> 指定被嵌套的内容输出到样式表的顶层;</strong>32 font-size:16px;33 }34 .main-sec-detail {35 font-size:14px;36 }37 }38 }39 Css:40 .main-sec {41 font-size:12px;42 }43 .main-sec-headline { <strong>// 编译后成功输出到样式表的顶层;</strong> 44 font-size:16px;45 }46 .main-sec-detail {47 font-size:14px;48 }49 50 3.if操作符51 @mixin col-sa ($width:50%){52 <strong>// 使用type-of()方法:检测$width是否是数值类型;</strong>53 @if type-of($width) != number {54 <strong>// #{}:可以引用Sass的变量;--Ruby语法;</strong>55 //<strong> @error:表示错误信息;</strong>56 @error "$width必须是一个数值类型,你输入的width是:#{$width}.";57 }58 59 // 使用unitless()方法:判断当前的数值是否跟有单位;60 //<strong> 前置not表示否定,双重否定表示肯定;</strong>61 @if not unitless($width){ //<strong> 判断数值有单位;</strong>62 @if unit($width) != "%" { //<strong> 如果单位不是%;</strong>63 @error "$width必须是一个数值类型,你输入的width是:#{$width}.";64 }65 } @else { //<strong> 判断数值没有单位;</strong>66 @warn "$width必须是一个数值类型,你输入的width是:#{$width}.";67 <strong> $width:(percentage($width)/100); // 换算成带%单位的数值; </strong>68 }69 @media (min-width:768px){70 width:$width;71 float:left;72 }73 }74 75 4.Sass的输出格式76 //<strong> 在config.rb配置文件里;</strong>77 >1.output_style = :expanded or :nested or :compact or :compressed78 >>0.:expanded => 编译后的文件是展开的;79 >>1.:nested => 根据嵌套,在输出的时候代码缩进;80 >>2.:compact => 将所有的属性汇总到一行;选择器之间的关系更清晰;81 >>3.:compressed => 将所有的代码压缩以占用最小的空间;
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