Question

To center an HTML element I can use the CSS left: 50%;. However, this centers the element with respect to the whole window.

I have an element which is a child of a <div> element and I want to center the child with respect to this parent <div>, not the whole window.

I do not want the container <div> to have all its content centered, just the one specific child.

Answer 1

Set text-align:center; to the parent div, and margin:auto; to the child div.

#parent {
    text-align:center;
    background-color:blue;
    height:400px;
    width:600px;
}
.block {
    height:100px;
    width:200px;
    text-align:left;
}
.center {
    margin:auto;
    background-color:green;
}
.left {
    margin:auto auto auto 0;
    background-color:red;
}
.right {
    margin:auto 0 auto auto;
    background-color:yellow;
}

<div id="parent">
    <div id="child1" class="block center">
        a block to align center and with text aligned left
    </div>
    <div id="child2" class="block left">
        a block to align left and with text aligned left
    </div>
    <div id="child3" class="block right">
        a block to align right and with text aligned left
    </div>
</div>

This a good resource to center mostly anything.
http://howtocenterincss.com/