#main_image_area{background-color:#333}#vr_studio_area{margin-top:15px}#vr_studio_area iframe{height:350px}#principle{margin-top:40px}.youtube_area{margin:10px 0}#youtube_gallery{display:flex;flex-wrap:wrap;margin-top:30px}#youtube_gallery .youtube_area{height:250px;margin:0;padding:5px;width:50%}@media only screen and (max-width:768px){#container.responsible #vr_studio_area{margin-bottom:0}}@media only screen and (max-width:640px){#container.responsible #youtube_gallery .youtube_area{height:240px}}@media only screen and (max-width:480px){#container.responsible #vr_studio_area iframe{height:250px}#container.responsible #youtube_gallery .youtube_area{flex:auto;width:100%}}