@page {
	size: A4;
}
html, body {
  margin: 0;
  padding: 0;
  background: #f4f4f4;
}

body {
	display: flex;
	justify-content: center;
	font-family: "Times New Roman", Times, serif;
	line-height: 22px;
}

.surf{
	position:fixed;z-index:1000;width:200;height:auto;max-width:auto;
	left:0;
}

.page {
	background: white;
	width: 21cm;
	min-height: 29.7cm;
	padding: 1cm;
	box-sizing: border-box;
	box-shadow: 0 0 5px rgba(0,0,0,0.1);
	color: #000;
	padding-top:20px;
	font-size:20px;
	line-height: 1.5;
	-webkit-text-size-adjust: 100%;
}

h1 {
	margin: 0;
	text-align: center;
	padding:10px;
	border-bottom: 2px solid black;
}

h2 {
	font-size: 34px;
	margin-top: 0.7em;
	padding-bottom: 0.2em;
	border-bottom: 1px solid black;
}

p,ul,span {
	margin: 0.5em 0;
}

br{
	margin-bottom:10px;
}


ul {
	padding-left: 1em;
	margin: 0.5em 0;
}

li {
	font-size:20px;
	margin-bottom: 0.5em;
	line-height: 1.5;
    -webkit-text-size-adjust: 100%;
}

.deftext{
	border-bottom: 1px solid black;
}
.definition{
	margin-bottom:20px;
	margin-top:10px;
	
	padding-left:4px;
	border-left: 4px solid black;
}

table {
	border-collapse: collapse;
	width: 50%;
	margin: 20px 0;
	font-family: Arial, sans-serif;
}

thead {
	background-color: #f2f2f2;
}

th, td {
	border: 1px solid black;
	padding: 8px;
	text-align: left;
}

img{
	display:block;
	max-width:100%;
}

.task{
	margin-top:40px;
	border: 1px solid black;
}

.std_formula{
	display: inline-block;
	width:100%;
	margin-top:40px;
	text-align:center;
	border: 1px solid black;
}

.double_underline{
	border-bottom: 3px double black;
}
.normal_underline{
	border-bottom: 3px solid black;
}


@media print {
	body {
		background: none;
	}
	.page {
		box-shadow: none;
		margin: 0;
	}
}
pre{
	background-color: #dddddd;
}

@media screen and (max-width: 990px) {
	.page {
		width:100vw;
		margin:0px;
		padding:2.5%;
	}
}