[html] How can I center a div within another div?

I suppose that the #container will be centered within #main_content. However, it is not. Why isn't this working, and how can I fix it?

#main_content {
  top: 160px;
  left: 160px;
  width: 800px;
  min-height: 500px;
  height: auto;
  background-color: #2185C5;
  position: relative;
}

#container {
  width: auto;
  height: auto;
  margin: 0 auto;
  padding: 10px;
  position: relative;
}

<div id="main_content">
  <div id="container">
  </div>
</div>

Maybe you want as this: Demo

HTML

<div id="main_content">
    <div id="container">vertical aligned text<br />some more text here
    </div>
</div>

CSS

#main_content {
    width: 500px;
    height: 500px;
    background: #2185C5;
    display: table-cell;
    text-align: center;
    vertical-align: middle;
}

#container{
    width: auto;
    height: auto;
    background: white;
    display: inline-block;
    padding: 10px;
}

How?

In a table cell, vertical align with middle will set to vertically centered to the element and text-align: center; works as horizontal alignment to the element.

Noticed why is #container is in inline-block because this is in the condition of the row.

If you don't want to set a width for #container, just add

text-align: center;

to #main_content.

I would try defining a more specific width, for starters. It's hard to center something that already spans the entire width:

#container {
    width: 400px;
}

Here is a new way to easily center your div using Flexbox display.

See this working fiddle: https://jsfiddle.net/5u0y5qL2/

Here is the CSS:

.layout-row {
    box-sizing: border-box;
    display: -webkit-box;
    display: -webkit-flex;
    display: flex;
    -webkit-box-direction: normal;
    -webkit-box-orient: horizontal;
    -webkit-flex-direction: row;
    flex-direction: row;
}

.layout-align-center-center {
    -webkit-box-align: center;
    -webkit-align-items: center;
    -ms-grid-row-align: center;
    align-items: center;
    -webkit-align-content: center;
    align-content: center;
    -webkit-box-pack: center;
    -webkit-justify-content: center;
    justify-content: center;
}

To make a div in center. There isn't any need to assign the width of the div.

A working demo is here:

http://jsfiddle.net/6yukdmwq/

    .container {
        width: 100%;
        height: 500px;
        display: table;
        border: 1px solid red;
        text-align: center;}

    .center {
        display: table-cell;
        vertical-align: middle;
    }

    .content {
        display: inline-block;
        text-align: center;
        border: 1px solid green;
    }

    <section class="container">
        <div class="center">
            <div class="content">
                <h1>Helllo Center Text</h1>
            </div>
        </div>
    </section>

You can center float div with this little code:

#div {
    width: 200px;
    height: 200px;
    position: absolute;
    left: 50%;
    top: 50%;
    
    margin-top: -100px;
    margin-left: -100px;
}

Here is the solution:

#main_content {
    background-color: #2185C5;
    height: auto;
    margin: 0 auto;
    min-height: 500px;
    position: relative;
    width: 800px;
}

Try to get the position:relative; in your #container. Add an exact width to #container:

#main_content {
    top: 160px;
    left: 160px;
    width: 800px;
    min-height: 500px;
    height: auto;
    background-color: #2185C5;
    position: relative;
}

#container {
    width: 600px;
    height: auto;
    margin: auto;
    padding: 10px;
}

Working demo

It would work giving the #container div width:80% (any width less than the main content and have given in %, so that it manages well from both left and right) and giving margin:0px auto; or margin:0 auto; (both work fine).

It is because your width is set to auto. You have to specify the width for it to be visibly centered.

Your #container spans the whole width of the #main_content. That's why it seems not centered.

Make the CSS content this way...

#main_content {
    top: 160px;
    left: 160px;
    width: auto;
    min-height: 500px;
    height: auto;
    background-color: #2185C5;
    position: relative;
 }

#container {
    height: auto;
    width: 90%;
    margin: 0 auto;
    background-color: #FFF;
    padding: 10px;
}

A working example is here: http://jsfiddle.net/golchha21/mjT7t/

Everyone said it, but I guess it won't hurt saying it again.

You need to set the width to some value. Here is something simpler to understand.

http://jsfiddle.net/XUxEC/

Another interesting way: fiddle

CSS

    .container {
        background: yellow;
        width: %100;
        display: flex;
        flex-direction: row;
        flex-wrap: wrap;
        justify-content: center;
        align-items: center;
    }

    .centered-div {
        width: 80%;
        height: 190px;
        margin: 10px;
        padding: 5px;
        background: blue;
        color: white;
    }

HTML

    <div class="container">
        <div class="centered-div">
            <b>Enjoy</b>
        </div>
    </div>

This will work fine I think, though you might need to reset "top:200px;" according to your needs:

#main_content {
    top: 160px;
    left: 160px;
    width: 800px;
    min-height: 500px;
    height: auto;
    background-color: #2185C5;
    position: relative;
    border: 2px solid #CCCCCC;
}

#container {
    width: 100px;
    height: 20px;;
    margin: 0 auto;
    padding-top: 10px;
    position: relative;
    top: 200px;
    border: 2px solid #CCCCCC;
}

Now just define your

#main_content text-align:center and define your #container display:inline-block;

as like this:

#main_content {
    text-align: center;
}

#container{
    display: inline-block;
    vertical-align: top;
}

You must assign a width to the div you want to center.

Like this:

#container {
    width: 500;
    margin: 0 auto;
    padding: 10px;
}

More information and examples on these links:

• CSS Layout - Horizontal & Vertical Align

• http://www.w3schools.com/css/tryit.asp?filename=trycss_align_container

Use margin:0 auto; to the child div. Then you can center the child div inside the parent div.

Technically, your inner DIV (#container) is centered horizontally. The reason you can't tell is because with the CSS width: auto property the inner DIV is expanding to the same width as its parent.

See this fiddle: http://jsfiddle.net/UZ4AE/

#container {
    width: 50px;
    height: auto;
    margin: 0 auto;
    padding: 10px;
    position: relative;
    background-color: red;
}

In this example, I simply set the width of #container to 50px and set the background to red so that you can see that it is centered.

I think the real question is "How do I center elements horizontally with CSS?" and the answer is (drum roll please): it depends!

I won't do a full rehash of the myriad ways to center things with CSS when W3Schools does it so nicely here: http://www.w3schools.com/css/css_align.asp but the basic idea is that for block level elements you simply specify the desired width and set the left and right margins to auto.

.center {
    margin-left: auto;
    margin-right: auto;
    width: 50px;
}

Please note: This answer only applies to block level elements! To position an inline element, you will need to use the text-align: center property on the first block parent.

.parent {
    width: 500px;
    height: 200px;
    border: 2px solid #000;
    display: table-cell;
    vertical-align: middle;
}

#kid {
    width:70%; /* 70% of the parent */
    margin:auto;
    border:2px solid #F00;
    height: 70%;
}

This does solve the problem very well (tested in all new browsers), where the parent div has class="parent" and the child div has id="kid".

That style centers both horizontally and vertically. Vertical center can only be done using complicated tricks--or by making the parent div function as a table-cell, which is one of the only elements in HTML that properly supports vertical alignment.

Simply set the height of the kid, margin auto, and middle vertical alignment, and it will work. It's the easiest solution that I know.

Try to add

text-align: center;

to your parent container CSS declaration. And the following to the child container:

display: inline-block;

It must do the trick.

#main_content {
    width: 400px;
    margin: 0 auto;
    min-height: 300px;
    height: auto;
    background-color: #2185C5;
    position: relative;
}

#container {
    width: 50%;
    height: auto;
    margin: 0 auto;
    background-color: #CCC;
    padding: 10px;
    position: relative;
}

Try this. It tested OK. There is a live check on jsfiddle.

If you set width: auto to a block element, then the width would be 100%. So it really doesn't make much sense to have the auto value here. It is really the same for height, because by default any element is set to an automatic height.

So finally your div#container is actually centered, but it just occupies the whole width of its parent element. You do the centering right, and you need just to change the width (if needed) to see that it is really centered. If you want to center your #main_content then just apply margin: 0 auto; on it.

I have used the following method in a few projects:

https://jsfiddle.net/u3Ln0hm4/

.cellcenterparent{
  width: 100%;
  height: 100%;
  display: table;
}

.cellcentercontent{
  display: table-cell;
  vertical-align: middle;
  text-align: center;
}

Try this one if this is the output you want:

<div id="main_content" >
    <div id="container">
    </div>
</div>

#main_content {
    background-color: #2185C5;
    margin: 0 auto;
}

#container {
    width: 100px;
    height: auto;
    margin: 0 auto;
    padding: 10px;
    background: red;
}

* {
  box-sizing: border-box;
}

#main_content {
  top: 160px;
  left: 160px;
  width: 800px;
  min-height: 500px;
  height: auto;
  background-color: #2185c5;
  position: relative;
}

#container {
  width: 50%;
  height: 50%;
  margin: auto;
  padding: 10px;
  position: absolute;
  border: 5px solid yellow;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
}

Without setting the width, it will get the maximum width it can get. So you cannot see that the div has centered.

#container
{
    width: 50%;
    height: auto;
    margin: auto;
    padding: 10px;
    position: relative;
    background-color: black;  /* Just to see the different */
}