body {
	margin: 0;
	border: 0;
	/*Apple中国 12px/18px*/
	font: /*12px/18px*/ 14px/24px "Lucida Grande","Lucida Sans Unicode",Helvetica,Arial,Verdana,sans-serif;
}

body::-webkit-scrollbar { 
	width: 0 !important 
}

.header {
	background: #000000;
	color: white;
	height: 100px;
	width: 100%;

	display: flex;
	justify-content: center;
	align-items: center;
	flex-direction: column;

	position: fixed;
	top: 0;
}

.header-title {
	text-align: center;
	font-size: 32px;
	line-height: 48px;
}

.content {
	margin-top: 100px;
}

.minue {
	font-size: 14px; 
	line-height: 24px;
	text-align: left;

	padding: 20px;
	padding-left: 40px;

	position: fixed;
	top: 100px;
}

.minue ul {
	padding: 20px;
	list-style: none;
	cursor: pointer;
}

#product {
	color: #0070c9
}


.product_div {
	margin-left: 15%;

	background: #fafafa;
	padding: 20px;

	width: 50%;
}

.theory_div {
	margin-left: 15%;

	background: #fafafa;
	padding: 20px;

	width: 50%;
	display: none;
}

.experiment_div {
	margin-left: 15%;

	background: #fafafa;
	padding: 20px;

	width: 50%;
	display: none;
}


.footer {
	background: #000000;
	color: white;
	height: 200px;
	width: 100%;

	display: flex;
	flex-direction: row;
	align-items: center;
	justify-content: space-around;

	margin-bottom: 0;
}

a {
	text-decoration: none;
}

a:link {
	color: #0070c9;
} 

a:visited {
	color: #0070c9;
} 

.footer a {
	color: white;
}

a:hover {
	color: #0070c9;
	text-decoration: underline;
}
.refer_links {
	text-decoration: underline;
}

.product-name {
	font-size: 14px;
}

.product_e img {
	width: 90px;
}

#oo img {
	width: 80px;
	margin: 5px;
}

.product_e {
	text-align: center;

	display: flex;
	direction: row;
	justify-content: left;
	align-content: center;
	align-items: center;
}

.desc {
	text-align: left;
	padding: 5px;
}

#products {
	margin-top: 30px;
}

#easy_learn {
	margin-top: 20px;
}

#oo {
	margin-top: 20px;
}

#service {
	margin-top: 20px;
	margin-bottom: 20px; 
}

.footer-e {
	text-align: center;
}

#email {
	display: flex;
	align-items: center;
	align-content: center;
	justify-content: center;
}

#email span {
	padding: 0 5px;
}

.catg {
	margin-top: 20px;
}

.catg-subject {
	font-size: 26px; 
	line-height: 39px;
}

.ctag-title {
	font-size: 14px;
	line-height: 24px;
	font-weight: 700;
}

.video {
	width: 100%;
	margin: 0 auto;
	display: flex;
	flex-direction: column;
	flex-wrap: wrap;
	justify-content: center;
	align-items: center;
	align-content: space-between;
}

.video a, img {
	width: 60%;
}

#contact img {
	width: 90px;
}

#email img {
	width: 30px;
}

#copyright {
	padding-top: 90px;
}

@media screen and (min-width: 400px) {
	.theory_div {
		height: 900px;
	}

	.product_div {
		height: 1000px;
		
	}

	.experiment_div {
		height: 600px;
	}
}

@media screen and (max-width: 400px) {
	.minue {
		display: none;
	}

	.product_div {
		margin: 10px auto;
		width: 90%;
		display: block;
	}

	.theory_div {
		margin: 10px auto;
		width: 90%;
		display: block;
	}

	.video a, img {
		width: 70%;
	}

	.experiment_div {
		margin: 10px auto;
		width: 90%;
		display: block;
	}

	.footer {
		height: 450px;
		padding: 0 20px;
		width: 90%;
		flex-direction: column;
	}

	.footer-e {
		width: 100%;
		margin: 10px auto;
	}

	#programming {
		width: 100%;
		display: flex;
		flex-direction: column;
		align-items: center;
		justify-content: center;
	}

	#copyright {
		padding-top: 0px;
		order: 4;
	}
}