body {
	font-family: 'Times New Roman', Times, serif;
	margin: auto;
	padding: 20px;
}

.main {
	width: 100%; /* 或者任何你想要的宽度 */
	height: 100%; /* 或者任何你想要的宽度 */
}

h1 {
	color: #333;
	margin: 20px auto;
	text-align: center;
	font-family: 'Times New Roman', Times, serif;
	font-size: 2.5em;
	font-weight: bold;
}

h3 {
	color: #333;
	font-size: 36px;
	margin-bottom: 15px;
	margin-top: 10px auto;
	font-weight: bold;
}

p {
	color: #333;
	font-size: 24px;
	text-indent: 1em;
}

.pic1,.pic2,.pic3 {
	margin: 10px auto;
	border: 0px;
	text-align: center;
}

.pic1 {
	width: 800px;
	height: 404px;
}

.pic2 {
	width: 500px;
	height: 403px;  
}

.pic3 {
	width: 800px;
	height: auto;
}

.pic img {
	width: 100%;
	height: 100%;
}

.figtitle {
	color: #333;
	font-size: 20px;
	text-align: center;
}

.liter {
	margin: 10px;
	font-size: 24px;
}

#back-to-top {
	position: fixed;
	bottom: 20px;
	right: 20px;
	background-color: #333;
	color: white;
	border: none;
	border-radius: 5px;
	padding: 10px 15px;
	z-index: 999;
	cursor: pointer;
	transition: opacity 0.3s;
	outline: none;
}

#back-to-top:hover {
	background-color: #555;
}

#back-to-top i {
	font-size: 24px;
}