@media screen and (min-width: 640px) {.video {width: 640px;height: 375px;line-height: 0px; margin: 0 auto;}}@media screen and (max-width: 640px) {.video {width: 100%;height: 270px;line-height: 0px;}}@media only screen and (min-device-pixel-ratio: 2),only screen and (-webkit-min-device-pixel-ratio: 2) {.tcp-logo-img {width: 50%;}} .video .top {margin-top: 20px;} .video .bottom {margin-bottom: 50px;}

北京，非初高三学生不组织线上学习，不留作业。