@media (min-width: 768px) {
    /* 在这里添加针对宽屏设备的样式规则 */
	.videobg{
		position: fixed;
		top: -3%;
		left: -3%;
		width: 106%;
		z-index: -1000;
	}
	.coverbg{
		position: fixed;
		top: 0%;
		left: 0%;
		width: 100%;
		height: 100%;
		background-color: #00000040;
		z-index: -999;
	}
}

@media (max-width: 767px) {
    /* 在这里添加针对窄屏设备的样式规则 */
	.videobg{
		position: fixed;
		top: -3%;
		left: -3%;
		height: 106%;
		z-index: -1000;
		margin-left: -190%;
	}
	.coverbg{
		position: fixed;
		top: 0%;
		left: 0%;
		width: 100%;
		height: 100%;
		background-color: #00000040;
		z-index: -999;
	}
}