How to make div's percentage width relative to parent div and not viewport

Question

Here is the HTML I am working with.

<div id="outer" style="min-width: 2000px; min-height: 1000px; background: #3e3e3e;">    <div id="inner" style="left: 1%; top: 45px; width: 50%; height: auto; position: absolute; z-index: 1;">      <div style="background: #efffef; position: absolute; height: 400px; right: 0px; left: 0px;"></div>    </div>  </div>

What I would like to happen is for the inner div to occupy 50% of the space given to its parent div(outer). Instead, is is getting 50% of the space available to the viewport, which means that as the browser/viewport shrinks in size, so does it.

Given that the outer div has min-width of 2000px, I would expect the inner div to be at least 1000px wide.

Answer 1

Specifying a non-static position, e.g., position: absolute/relative on a node means that it will be used as the reference for absolutely positioned elements within it http://jsfiddle.net/E5eEk/1/

See https://developer.mozilla.org/en-US/docs/Learn/CSS/CSS_layout/Positioning#Positioning_contexts

We can change the positioning context — which element the absolutely positioned element is positioned relative to. This is done by setting positioning on one of the element's ancestors.

#outer {    min-width: 2000px;     min-height: 1000px;     background: #3e3e3e;     position:relative  }    #inner {    left: 1%;     top: 45px;     width: 50%;     height: auto;     position: absolute;     z-index: 1;  }    #inner-inner {    background: #efffef;    position: absolute;     height: 400px;     right: 0px;     left: 0px;  }

<div id="outer">    <div id="inner">      <div id="inner-inner"></div>    </div>  </div>

Answer 2

Use position: relative on the parent element.

Also note that had you not added any position attributes to any of the divs you wouldn't have seen this behavior. Juan explains further.