bootstrap "center-block"

I'm using bootstrap to make a UI like the following：

 ------------------------------------------------ | | | div-outside | | ---------------------------- | | | | | | | | | | | div-inside | | | | | | | | | | | ---------------------------- | | | | | ------------------------------------------------- 

The code is:

 <div> <div> .... </div> </div> 

To make the inner div center at the outer div, I'm using. It works well if the screen is wider than a specific number, such as 1000px, but if the screen width is not big enough, the inner div will be adjacent to the right of outer div:

 ---------------------------------------- | | | div-outside | | ---------------------------- | | | | | | | | | | left | div-inside | | | margin | | | | | | | | ---------------------------- | | | | | ----------------------------------------- 

With Chrome's developer tool, I found that when the inner div is not centered, the left margin will be a fixed number (it seems have a lower bound). But when the screen's width is varying above the boundary value, the left margin number will vary according to the width thus making the inner div always centered. In fact, when the inner div is not horizontally centered, if I manually adjust the left margin number, then the inner div will be centered.

3 Answers

Your example is working. The problem is that the layout does not work if the screen width is smaller than 350px, because you have chosen a fixed width.

Demo

If the <div> should center all the time, use cols and offset:

<div> <div> <div> center with offset </div> </div> </div> 

Example offset

More information about Bootstrap's grid offsetting.

Bootstrap's .center-block contains nothing more than

.center-block { display: block; margin-right: auto; margin-left: auto; } 

There should be something else which is adding some other rules to your container. From the Inspector, try to check the CSS (fixed left margin) which you are talking about is getting added from which file.

I think this is what you're trying to do.

#app-layout-body { height: auto; margin: 0 auto; padding: 25px; position: relative; border: 5px solid red; text-align: center; } #div-register { border: 5px solid green; padding: 10px; background: red; color: white; }

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