Twitter Bootstrap 100% Height DIV

All outer containers (Including) html and body must be height 100%

HTML

<script src="http://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/2.0.1/bootstrap.min.js"></script>
<div class="container">
    <div class="ph">Page Header</div>
    <div class="panel panel-default">
            <div class="panel-heading">Panel header</div>
            <div class="panel-body" style="overflow-y: scroll">
              
            </div>
            <div class="panel-footer">
                <button class="btn btn-success">
                    Save
              </button>
            </div>
        </div>
</div>

CSS

@import url('https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css');

html,body{height:100%;}

.ph {
  padding-bottom: 16px;
}

.container {
    height:100%;
    padding: 16px;
}

.panel {
  height: 90%;
  overflow: hidden;
}

.panel-heading {
  height: 7%;
}

.panel-body {
  height: 84%;
}

.panel-footer {
  height: 9%;
}