@media screen and (max-width:640px){
	body{
		margin:0;
	}

	h1 {
		font-size:x-large;
	}

	h2 {
		font-size: large;
	}

	h3 {
		font-size: medium;
	}

	h4 {
		font-size: medium;
	}
}
@media screen and (min-width: 641px){

	article {
		width: 640px;
		border: solid black 1px;
		margin: 0 auto;
	}

	h1 {
		font-size:xx-large;
	}

	h2 {
		font-size: x-large;
	}

	h3 {
		font-size: larger;
	}

	h4 {
		font-size: large;
	}

	div#ToTopPage {
		width: 640px;
		border: solid black 1px;
	}

}

/* 共通 */
body {
	background-color: gray;
}

article {
	position: relative;
	background-color: white;
}

section {
	padding: 0 0.5em 1em 0.5em;
	position: relative;
	margin-top: 5px;
}

p {
	margin: 0;
	text-indent: 1em;
}

.top-margin {
	margin-top: 1em;
}

div.WrittenDate {
	margin-left: auto;
	padding-right: 1em;
	margin: 1em 0;
	text-align: right;
}

div.WrittenDate time {
	margin-right: 1em;
}

h1 {
	font-size: xx-large;
	margin: 0 0 1em 0;
	padding: 0.25em 0;
	border-top: 2px solid black;
	border-bottom: 2px solid black;
	border-left: 1px solid black;
	border-right: 1px solid black;
	border-radius: 5px;
	background-color: lightgray;
	text-align: center;
}

h2 {
	font-size: x-large;
	border-top: 1px solid black;
	border-bottom: 1px solid black;
	background-color: lightgray;
	padding: 0.25em 0.5em;;
	margin: 0.5em 0 0.25em 0;
}

h3 {
	font-size: large;
	border-bottom: 1px solid black;
	padding: 0.25em 0.5em;;
	margin: 0.5em 0 0.25em 0;
}

h4 {
	font-size: medium;
	border-bottom: 1px dotted black;
	padding: 0.25em 0.5em;;
	margin: 0.5em 0 0.25em 0;
}

h5 {
	text-decoration: underline;
	padding: 0.25em 0.5em;;
	margin: 0.5em 0 0.25em 0;
}

div#ToTopPage {
	position: relative;
	text-align: right;
	margin: auto;
	margin-top: 1px;
	padding-top: 3px;
	background-color: white;
}

/* 計算式とか周囲を枠で囲みたい時 */
.Ex {
	padding: 0.5em 1em;
	border: dotted 1px black;
	margin-bottom: 1em;
}

/* 目立たなくて良い注釈 */
.Annotation {
	color: gray;
	margin: 1em 0.5em;
	padding: 0.5em 1em;
	border: solid 1px gray;
}

/* 目立つ注釈 */
.Notes {
	margin: 1em 0.5em;
	padding: 0.5em 1em;
	border: solid 1px gray;
}

/*
 *	注意書き
 */
div.Attention {
	margin: 1em;
	padding: 0.5em;
	position: relative;
	background-color: #FFCCCC;
	border-radius: 5px;
	border: 1px solid red;
}

blockquote {
	border: dotted gray 1px;
}

table {
	border-collapse: collapse;
	border: 1px solid gray;
	margin: 0em 1em 1em 1em;
}

th {
	border: 1px solid gray;
	background-color: lightgray;
}

td {
	border: 1px solid gray;
}

dl {
	margin: 1em;
}

dt {
	font-weight: bold;
}