CodePen

HTML

            
              <div class="line">
  <div class="column">
    <div>One</div>
    <div>Two</div>
    <div>Three</div>
  </div>
  <div class="column">
    <div>One</div>
    <div>Two</div>
    <div>Three</div>
  </div>
  <div class="column sidebar">
    <p>Fake sidebar background.</p>
    <p>I must be <code>position: static;</code> or it won't work! But you can float me. Works IE8+</p>
  </div>
</div>
            
          
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CSS

            
              body {
  
}

.line {
  position: relative;
  text-align: center;
  z-index: 1;
}

.column {
  display: inline-block;
  text-align: left;
  vertical-align: top;
  width: 300px;
}

.column > div {
  outline: 1px solid red;
  padding: 1.5em;
}

.column > div:hover {
  height: 5em;
}

.sidebar {
  color: white;
  padding: 1em;
  width: 10em;
}

.sidebar:before {
  background: red;
  content: '';
  height: 100%;
  margin: -1em; /* undo .sidebar padding */
  padding: 0 1em; /* ignore top and bottom padding */
  position: absolute;
  width: inherit;
  z-index: -1;
}
            
          
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JS

            
              // http://css-tricks.com/forums/discussion/24458/annoying-layout-issue-#Item_3
            
          
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