[css] How to use border with Bootstrap

How can I solve this problem? When you add borders to a div, the div is not centered and the span12 class is not centered.

I would like to center the div with the borders

<div class="row" >
   <div class="span12" style="border: 2px solid black">
      <div class="row">
         <div class="span4">
            1
         </div>
         <div class="span4">
            2
         </div>
         <div class="span4">
            3
         </div>
      </div>
   </div>
</div>

What others have mentioned about border vs border box is definitely correct. You can still get this to work without having to create any custom classes though: http://jsfiddle.net/panchroma/yfzdD/

HTML

<div class="container">
<div class="row" >
    <div class="span12">
       <div class="row">
        <div class="span4"> 1 </div>
        <div class="span4"> 2 </div>
        <div class="span4"> 3 </div>
        </div><!-- end nested row -->
    </div><!-- end span 12 -->

</div> <!-- end row -->
</div><!-- end container -->

CSS

.span12{
border:solid 2px black;
background-color:grey;  
}  

Good luck!

If you are using Bootstrap 4 and higher try this to put borders around your empty divs use border border-primary here is an example of my code:

<div class="row border border-primary">
        <div class="col border border-primary">logo</div>
        <div class="col border border-primary">navbar</div>
    </div>

Here is the link to the border utility in Bootstrap 4: https://getbootstrap.com/docs/4.2/utilities/borders/

If you need a basic border around you just need to use bootstrap wells.

For example the code below:

<div class="well">Basic Well</div>

You can't just add a border to the span because it will break the layout because of the way width is calculate: width = border + padding + width. Since the container is 940px and the span is 940px, adding 2px border (so 4px altogether) will make it look off centered. The work around is to change the width to include the 4px border (original - 4px) or have another div inside that creates the 2px border.

Depending what size you want your div to be, you could utilize Bootstrap's built-in component thumbnail class, along with (or without) the grid system to create borders around each of your div items.

These examples on Bootstrap's website demonstrates the ease-of-use and lack of need for any special additional CSS:

<div class="row">
    <div class="col-xs-6 col-md-3">
        <a href="#" class="thumbnail">
            <img src="..." alt="...">
        </a>
    </div>
    ...
</div>

which produces the following div grid items:

or add some additional content:

<div class="row">
  <div class="col-sm-6 col-md-4">
    <div class="thumbnail">
      <img src="..." alt="...">
      <div class="caption">
        <h3>Thumbnail label</h3>
        <p>...</p>
        <p>
            <a href="#" class="btn btn-primary" role="button">Button</a>
            <a href="#" class="btn btn-default" role="button">Button</a>
       </p>
      </div>
    </div>
  </div>
</div>

which produces the following div grid items:

There's a property in CSS called box-sizing. It determines the total width of an element on your page. The default value is content-box, which doesn't include the padding, margin, or border of the element.

Hence, if you set a div to have width: 500px and 20px padding all around, it will take up 540px on your website (500 + 20 + 20).

This is what is causing your problem. Bootstrap calculates set widths for things just like the above example, and these things don't have borders. Since Bootstrap fits together like a puzzle, adding a border to one of the sides would yield a total width of 501px (continuing the above example) and break your layout.

The easiest way to fix this is to adjust your box-sizing. The value you would use is box-sizing: border-box. This includes the padding and border in your box elements. You can read more about box-sizing here.

A problem with this solution is that it only works on IE8+. Consequently, if you need deeper IE support you'll need to override the Bootstrap widths to account for your border.

To give an example of how to calculate a new width, begin by checking the width that Bootstrap sets on your element. Let's say it's a span6 and has a width of 320px (this is purely hypothetical, the actual width of your span6 will depend on your specific configuration of Bootstrap). If you wanted to add a single border on the right hand side with a 20px padding over there, you'd write this CSS in your stylesheet

.span6 {
  padding-right: 20px;
  border-right: 1px solid #ddd;
  width: 299px;
 }

where the new width is calculated by:

old width - padding - border

While it's probably not the correct way to do it, something that I've found to be a simple workaround is to simply use a box-shadow rather than a border... This doesn't break the grid system. For example, in your case:

HTML

<div class="container">
    <div class="row" >
        <div class="span12">
            <div class="row">
                <div class="span4">
                    1
                </div>
                <div class="span4">
                    2
                </div>
                <div class="span4">
                    3
                </div>
            </div>
        </div>
    </div>
</div>

CSS

.span12{
    -moz-box-shadow: 0 0 2px black;
    -webkit-box-shadow: 0 0 2px black;
    box-shadow: 0 0 2px black;
}

Fiddle

Unfortunately, that's what borders do, they're counted as part of the space an element takes up. Allow me to introduce border's less commonly known cousin: outline. It is virtually identical to border. Only difference is that it behaves more like box-shadow in that it doesn't take up space in your layout and it has to be on all 4 sides of the element.

http://codepen.io/cimmanon/pen/wyktr

.foo {
    outline: 1px solid orange;
}

As of Bootstrap 3, you can use Panel classes:

<div class="panel panel-default">Surrounded by border</div>

In Bootstrap 4, you can use Border classes:

<div class="border border-secondary">Surrounded by border</div>