样式表文件开发规范

    .
    ├── src         //源文件目录
        ├── less         //less 样式文件目录
            ├── reset.less       //通用样式重置
            ├── tools.less       //通用工具类css（clearfix, wordwrap, ...）
            ├── layout.less      //通用布局类css
            ├── grid.less        //栅格化 css
            ├── responsive.less  //基础响应式样式布局文件
    

    /*伪元素*/
    p::after{
        content: " ";
    }
    /*
        主要伪元素选择器：
        ::after, ::before, ::first-letter, ::first-line, ::selection
    */
    
    /*伪类*/
    a:hover{
        color: #000;
    }
    /*
        主要伪类选择器：
        :active, :checked, :disabled, :empty, :enabled, :first-child, :first-of-type, :focus, 
        :hover, :in-range, :invalid, :lang(language), :last-child, :last-of-type, :link, :not(selector),
        :nth-child(n), :nth-last-child(n), :nth-last-of-type(n), :nth-of-type(n), :only-of-type, :only-child,
        :optional, :out-of-range, :read-only, :read-write, :required, :root, :target, :valid, :visited
    */
    
    

    .
    ├── less                 //样式文件目录
        ├── home.less                   //默认页面最小宽度样式
        ├── home_width_l_1280.less      //浏览器宽度 <= 1280px && > min 样式
        ├── home_width_l_1680.less      //浏览器宽度 <= 1600px && > 1280 样式
        ├── home_width_l_1920.less      //浏览器宽度 <= 1920px && > 1600 样式
        ├── ...