How to Center Absolute Div Horizontally Using CSS

How to center absolute div horizontally using CSS?

You need to set left: 0 and right: 0.

This specifies how far to offset the margin edges from the sides of the window.

Like 'top', but specifies how far a box's right margin edge is offset to the [left/right] of the [right/left] edge of the box's containing block.

Source:
http://www.w3.org/TR/CSS2/visuren.html#position-props

Note: The element must have a width smaller than the window or else it will take up the entire width of the window.
You could use media queries to specify a minimum margin, and then transition to auto for larger screen sizes.

.container {
  left:0;
  right:0;

  margin-left: auto;
  margin-right: auto;

  position: absolute;
  width: 40%;

  outline: 1px solid black;
  background: white;
}

<div class="container">
  Donec ullamcorper nulla non metus auctor fringilla.
  Maecenas faucibus mollis interdum.
  Sed posuere consectetur est at lobortis.
  Vivamus sagittis lacus vel augue laoreet rutrum faucibus dolor auctor.
  Sed posuere consectetur est at lobortis.
</div>

Center absolute positioned div

If i understood your question then it will work as below.

You can do it in three ways.

No1 - Using position. Apply width 100% to button parent div and apply the button style as bellow.

.buy-btn{
    display: inline-block;       /* Display inline block */
    text-align: center;          /* For button text center */
    position: absolute;          /* Position absolute */
    left: 50%;                   /* Move 50% from left */
    bottom: 10px;                /* Move 10px from bottom */
    transform: translateX(-50%); /* Move button Center position  */
}

No2 - Using parent div, apply width 100% to your parent div and remove the postion absolute from button.

.parentDiv {
    width: 100%;            /* for full width */
    text-align: center;     /* for child element center */
 }

.buy-btn{
    display: inline-block;       /* Display inline block */
    text-align: center;          /* For button text center */
}

No3 - Using margin, apply width 100% to your parent div and remove the postion absolute from button.

.parentDiv {
    width: 100%;            /* for full width */
 }

.buy-btn{
    display: inline-block;       /* Display inline block */
    text-align: center;          /* For button text center */        
    margin: 0 auto;              /* For button center */
}

How can I center an absolutely positioned element in a div?

<body>

  <div style="position: absolute; left: 50%;">

    <div style="position: relative; left: -50%; border: dotted red 1px;">

      I am some centered shrink-to-fit content! <br />

      tum te tum

    </div>

  </div>

</body>

How to center horizontally an absolute button in a div?

Try to transform: translateX(-50%); your button

How to center contents of an absolute div horizontally

Use width:100% in absolute div

.home .center {
    position: absolute;
    bottom: 0;
    top:30px;
    text-align: center;
    width:100%;
}

Updated fiddle

Center absolutely positioned div horizontally with absolute children

I am not sure why you need to absolutely position the children. Is this what you are trying to achieve: http://jsfiddle.net/k65pxydx ?

.myAbsoluteContainer {
    text-align: center; /* Centers the elements horizontally */
}
.myAbsoluteChildElement {
    display: inline-block;
    vertical-align: middle; /* Centers the elements vertically */
}

center align position absolute object horizontally

A useful trick to center elements is to use the transform: translate style together with either top, margin-left left or margin-top.

To answer your question, you have to apply the following styles to your .slider a.downarrow element:

left: 50%;
transform: translateX(-50%);

The way this works is because if translate is used with a percentage value, its value is calculated based on the elements height/width on which it is applied on.

top, margin-left left and margin-top percentage values are calculated based on the parent element or in case the element has position: absolute applied to it based on the nearest parent with position: relative/absolute.

To center an element you just need to apply a value of 50% to either top, margin-left left or margin-top and a value of -50% to translate.

For left and margin-left you have to use translateX(-50%) and for the others translateY(-50%).

EDIT: Added an explanation

centering absolute div horizontally in relative table cell

Since you gave the absolutely positioned element a width, you would just have to add left: 0; right: 0; in order to center it horizontally.

Alternatively, since the element has a fixed, percentage-based width of 90%, you could also just use left: 5% to center it horizontally.

table {

  width: 100%;

  border: 1px solid;

  height: 200px;

  table-layout: fixed;

}

table td {

  position: relative;

  border: 1px solid

}

div {

  position: absolute;

  top: 20%;

  bottom: 30%;

  left: 0; right: 0;

  border: 1px solid;

  box-sizing: border-box;

  padding: 5px;

  width: 90%;

  margin: auto;

}

<html>

<table>

  <tr>

    <td>

      <div>Content</div>

    </td>

    <td> </td>

</table>

</html>

How to Center Absolute Div Horizontally Using CSS