.honbuntop img {
  display: block;
  margin: 0 auto;
  border: 1px solid #999;
  padding: 10px;
  background: #faf1d4;
  box-shadow: 2px 2px 6px rgba(0,0,0,0.2);
}
.honbuntop iframe {
  display: block;
  width: 100%;
  max-width: 100%;
  height: 450px;
  margin: 20px auto;
  padding: 10px;
  border: 1px solid #999;
  background: #faf1d4;
  box-shadow: 2px 2px 6px rgba(0,0,0,0.2);
  box-sizing: border-box;
}

@media screen and (max-width: 700px) {
  .container iframe {
    height: 300px;
  }
}