使用RUBY将值写入CSV列(Write value to CSV Column with RUBY)

 那么，用于居中#centered元素的CSS实际上是正确的！ 所以不要担心，你在那里正确的轨道。 
 
 问题实际上在于#centered元素的内容 - .content元素的样式。 给定position:absolute ，这意味着它从布局中取出，因此#centered的定位#centered没有影响（因为#centered没有position:relative ）。 
 
 有两种方法可以解决这个问题，我现在可以看到：首先，你可以添加position:relative对于#centered的定义，所以你的CSS看起来像这样： 
 
#centered {
    width:900px;
    height:auto;
    margin:0px auto;
    position:relative;
}
 
 这将导致您的绝对定位.content相对于#centered元素定位。 或者（和我喜欢的方法），你可以删除.content上的绝对定位，因为它似乎不需要在那里。 删除一些其他不必要的属性并添加一个边距，它看起来像这样： 
 
.content {
    margin-top:115px;
    background:none;
}
 
 这是第二个解决方案的JSFiddle演示 。 如果展开视口，您将看到元素现在在屏幕中居中。 请注意，如果您插入服务器端的内容不是绝对定位的（或者更确切地说，将在文档的流程中），则甚至不需要margin-top:115px ，因为您添加的任何内容都将只需根据需要向下推动.content元素即可。 
 
 如果这不是你想要的，请告诉我，我会很乐意进一步提供帮助。 祝你好运！ 

Well, your CSS for centering the #centered element is in fact correct! So don't worry, you were on the right track there.
 
The problem actually lies with the content of the #centered element - the styling of the .content element. It is given position:absolute, which means it gets taken out of the layout, and as such the positioning of #centered has no effect over it (since #centered does no have position:relative).
 
There are two ways to fix this that I can see right now: First, you could add position:relative to the definition for #centered, so your CSS looks like this:
 
#centered {
    width:900px;
    height:auto;
    margin:0px auto;
    position:relative;
}
 
This will cause your absolutely-positioned .content to be positioned relative to the #centered element. Alternatively (and the approach I prefer), you can remove the absolute positioning on .content, since it doesn't seem to needed to be there. With removal of some other attributes rendered unnecessary and adding of a margin instead, it would look like this:
 
.content {
    margin-top:115px;
    background:none;
}
 
Here's a JSFiddle demonstration of the second solution. If you expand the viewport, you'll see that the elements are now centered in the screen. Note that if the content you're inserting server-side won't be absolutely positioned (or rather, will be in the flow of the document), the margin-top:115px isn't even necessary, since any content you add will simply push the .content element downwards as needed.
 
If this isn't what you were looking for, let me know and I'll be happy to help further. Good luck!