1. visibility：hidden;与display:none;的区别
   1. visibility：hidden;仅隐藏块元素内容
   2. display:none;完全隐藏块元素（包括占位）
2. 分支主题 3
3. 1.学习lynda Learning css2视频
   1. @import
   2. incorporating css in html
      1. grouping selectors
      2. types of elements
         1. 两种元素:块元素和行内元素
            1. 块元素和行内元素的区别
            2. 在页面中流方式不同
         2. css 指定元素模式的方法:display
            1. block
            2. inline
            3. none
            4. list-item
            5. ...
      3. <div>和<span>
         1. <div>是块元素\<span>是行内元素
   3. color
      1. foreground: color
      2. background :background-color
   4. layout
      1. float
         1. float和流的区别？
      2. box model
         1. border
            1. border-width
            2. border-top-width
            3. ...
            4. borer-color
            5. border-style
         2. margin
            1. margin:<top> <right> <bottom> <left>
         3. padding
         4. element position
            1. z-index:元素层级优先级
         5. clear
            1. 和float属性配合使用
         6. Layer presentation
         7. overflow
            1. visible
            2. hidden
            3. scroll
            4. auto
         8. visibility
            1. hidden
            2. visible
            3. collapse
   5. 伪类：first-line
   6. background
      1. background-image:url("<localtion>");
      2. background-repeat
      3. background-attachment
         1. scroll
         2. fixed
         3. inherit
      4. background-position
   7. typography
      1. font-family
      2. font-style
         1. oblique
         2. italic
         3. normal
      3. font-weight
      4. font-size
      5. line-height
      6. font-variant
         1. narmal
         2. small-caps
4. 分支主题 2