Popup window with transform positioning

CSS3, HTML5

by Nik

HTML

<div class="__holder">
        <div class="__box">
            <h2>Some header</h2>
            Some bunch of content etc
        </div>
    </div>

CSS

* {
    font: 11px Calibri,Arial,sans-serif;
    color: #ccc;
    padding: 0px;
    margin: 0px;
}
h2 {
    color: #333;
    font-size: 16px;   
}
    .__holder
    {
        position: fixed;
        z-index: 15000;
        top: 0;
        right: 0;
        bottom: 0;
        left: 0;
    
        width: 100%;
        height: 100%;
    
        background-color: rgba(0,0,0,.5);
    }
    .__box
    {
        position: absolute;
        z-index: 16000;
        top: 50%;
        left: 50%;
    
        -webkit-box-sizing: border-box;
           -moz-box-sizing: border-box;
                box-sizing: border-box;
        margin-right: -50%;
        padding: 0;
    
        transform: translate(-50%, -50%);
    
        -webkit-border-radius: 6px;
           -moz-border-radius: 6px;
                border-radius: 6px;
        background-color: #fff;
        -webkit-box-shadow: 0 0 18px 3px rgba(0, 0, 0, .07);
           -moz-box-shadow: 0 0 18px 3px rgba(0, 0, 0, .07);
                box-shadow: 0 0 18px 3px rgba(0, 0, 0, .07);
        
        padding: 30px;
    }