title: css position guide
body: <p>In my work,I often use the css to make the page layout,however I found that I can not make it well beacuse of the css position.</p>
  
  <p>I know the float/absolute/releative and etc.</p>
  
  <p>But when I use them I often can not get what I wanted. Expecially when I use the nested layout,for example,using a absoluted position element within a float element and etc.</p>
  
  <p>I have read the w3cschool tutorial,but I also can not exactly sure I understand it.</p>
  
  <p>So I wonder if there is any detailed css guide? Or some common rules when I layout the element?</p>