img,
iframe {
  max-width: 100%;
}

.embed-container {
  position: relative; 
  padding-bottom: 56.25%; /* ratio 16x9 */
  height: 0; 
  overflow: hidden; 
  width: 100%;
  height: auto;
}
.embed-container iframe {

  position: absolute; 
  top: 0; 
  left: 0; 
  width: 100%; 
  height: 100%; 
}
/* ratio 4x3 */
.embed-container.ratio4x3 {
  padding-bottom: 75%;
}


#armadilloContentContainer img { max-width: 100%; height: auto; }

/* Responsive iFrame MindMeister */
.mindmeister_iframe {position: relative;padding-bottom: 75%;height: 0;overflow: hidden;}
.mindmeister_iframe iframe {position: absolute;top:0;left: 0;width: 100%;height: 100%;}



/* YouTube center */
* {
    box-sizing: border-box;
}

html, body {
    height: 100%;
}

body {
    margin: 0;
    border: 2px solid red;
}

.your-centered-div img {
    display: block;
    width: 100%;
    height: auto;
}

.container {
    width: 100%;
    float: left;
}

.your-centered-div {
    max-width: 560px; /* you have to have a size or this method doesn't work */
    max-height: 315px;
    margin-right: auto;
    margin-left: auto;
}