.video-container {
    position: relative;
    padding-bottom: 56.25%;
    padding-top: 30px;
    height: 0;
    overflow: hidden;
}
 
.video-container iframe,  
.video-container object,  
.video-container embed {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}

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

/* スマホ用 */
@media screen and (max-width: 767px) {
  .fb-container {
    width: 100%;
    max-width: 500px;
  }
}
 
/* PC用 */
@media screen and (min-width: 768px) {
  .fb-container {
    width: 500px;
  }
}