.box_slider_video{max-width:1040px; overflow: hidden; margin: 20px auto 30px auto;}
.slider_preview{float: left; margin: 3px 10px 3px 10px;}
.slider_preview:nth-child(3){margin-right: 0px;}
.dop_obrab {}

@media only screen and (max-width:1200px){
.box_slider_video {max-width:720px;}
.slider_preview{margin: 3px 10px 3px 20px;}
.slider_preview:nth-child(3){display: none;}
}
@media only screen and (max-width:820px){
.box_slider_video {max-width:310px;}
.slider_preview:nth-child(2){display: none;}
.dop_obrab {}
}

@media only screen and (max-width:600px){

}