How to apply child:hover but not parent:hover

Question

With the following html, when I hover over child, I get a green background on parent. How can I stop that from happening? I do want the green background if I am hovering outside of the child element.

CSS3 is fine.

.parent {
  padding: 100px;
  width: 400px;
  height: 400px;
}

.parent:hover {
  background-color: green;
}

.child {
  padding: 100px;
  width: 200px;
  height: 200px;
}

.child:hover {
  background-color: blue;
}

<div class="parent">
  <div class="child">Child</div>
</div>

Answer 1

So this is REALLY ugly, but it works (kind of). I'm basically creating a duplicate of parent as a sibling of child. parent-overwrite is hidden by default, then displayed on the hover of child. Chrome doesn't like it unless you use the + selector instead of the ~ selector. This isn't very scalable, but it may work.

As the other guys posted, javascript would likely be a better solution.

 <style>
  .parent { padding: 100px; width: 400px; height:400px; position: relative; z-index: 998; }
  .parent:hover { background-color: green; }
  .child { padding: 100px; width: 200px; height:200px; position: relative; z-index: 1000; }
  .child:hover { background-color: blue; }
  .parent-overwrite { padding: inherit; width: inherit; height: inherit; position: absolute; top: 0; left: 0; z-index: 999; background-color: #FFF; display: none; }
  .child:hover ~ .parent-overwrite { display: block; }
</style>

<div class="parent">
    <div class="child">Child</div>
    <div class="parent-overwrite"></div>
</div>

Answer 2

I can only do this with adding additional markup. An empty div needs to be added that essentially functions as the parent background. Take a look at the CSS here.

HTML Part:

  <div class="parent">
    Parent
    <div class="child">
      Child
      <div class="grandson">
        Grandson
        <div class="grandson-bg"></div>
      </div>
      <div class="child-bg"></div>
    </div>
    <div class="parent-bg"></div>
  </div>

CSS part:

article, aside, figure, footer, header, hgroup, menu, nav, section { display: block; }

  .parent { display: block; position: relative; z-index: 0;
            height: auto; width: auto; padding: 25px;
          }

  .parent-bg { display: block; height: 100%; width: 100%; 
               position: absolute; top: 0px; left: 0px; 
               border: 1px solid white; z-index: 0; 
             }
  .parent-bg:hover { border: 1px solid red; }

  .child { display: block; position: relative; z-index: 1; 
           height: auto; width: auto; padding: 25px;
         }

  .child-bg { display: block; height: 100%; width: 100%; 
              position: absolute; top: 0px; left: 0px; 
              border: 1px solid white; z-index: 0; 
            }
  .child-bg:hover { border: 1px solid red; }

  .grandson { display: block; position: relative; z-index: 2; 
              height: auto; width: auto; padding: 25px;
            }

  .grandson-bg { display: block; height: 100%; width: 100%; 
                 position: absolute; top: 0px; left: 0px; 
                 border: 1px solid white; z-index: 0; 
               }
  .grandson-bg:hover { border: 1px solid red; }

http://jsbin.com/ubiyo3/edit