Google maps embed iframe – респонсив

<style>
    .google-maps {
        position: relative;
        padding-bottom: 30%; // This is the aspect ratio
        height: 0;
        overflow: hidden;
    }
    .google-maps iframe {
        position: absolute;
        top: 0;
        left: 0;
        width: 100% !important;
        height: 100% !important;
    }
</style>
<br /><br /><center><h3>Map</h3><br /></center>
<div class='google-maps'>
<iframe src='https://www.google.com/maps/embed?pb=!1m18!1m12!1m3!1d2932.58550931219!2d23.29158247261225!3d42.69132162380618!2m3!1f0!2f0!3f0!3m2!1i1024!2i768!4f13.1!3m3!1m2!1s0x40aa85232c054953:0x408417d08050add6!2sBusiness+Centre+Serdika!5e0!3m2!1sen!2sbg!4v1468307728158&quot; width='600' height='450' frameborder='0' style='border:0' allowfullscreen></iframe>
</div>