@charset "Shift_JIS";
ヘッダーを幅いっぱいにする為のボックス 
<div id="headerbg">
ヘッダー 
<div id="header">
ここに内容を書き込む
</div>
ヘッダー終わり 
</div>
ヘッダーを幅いっぱいにする為のボックス終わり 
 
メインボックス 
<div id="container">
ここに内容を書き込む
</div>
メインボックス終わり 
 
フッターを幅いっぱいにする為のボックス 
<div id="footerbg">
フッター 
<div id="footer">
ここに内容を書き込む
</div>
フッター終わり 
</div>
フッターを幅いっぱいにする為のボックス終わり 
このhtmlに対するスタイルシートが下記になります。

/* ヘッダーを幅いっぱいにする為のボックス*/
#headerbg {
background-image: url(画像ファイルのurl);
width:100%;
min-width:1000px;
}
/* ヘッダー*/
#header       {
	width: auto;
	height: auto;
	text-align: center;
	background-position: center;
	margin-right: auto;
	margin-left: auto;
	padding-top: 0px;
	margin-top: 0px;
}
a {
	text-decoration: none;
	border-top-width: 0px;
	border-right-width: 0px;
	border-bottom-width: 0px;
	border-left-width: 0px;
	border-top-style: none;
	border-right-style: none;
	border-bottom-style: none;
	border-left-style: none;
}
/* メインボックス*/
#container {
	width: auto;
	margin-right: auto;
	margin-left: auto;
	height: auto;
}
.header {
	height: auto;
	width: auto;
	padding: 0px;
	margin-top: 0px;
	margin-right: auto;
	margin-bottom: 0px;
	margin-left: auto;
}
.header2 {
	height: auto;
	width: auto;
	top: 0px;
	padding: 0px;
	margin: 0px;
	background-image: url(itoback.png);
	background-repeat: repeat-x;
	background-position: center top;
}
/* フッターを幅いっぱいにする為のボックス*/
#footerbg {
	width: auto;
	min-width: 1000px;
	height: auto;
	background-repeat: repeat-x;
	background-position: top;
	background-color: #D81F17;
}
/* フッター*/
#footer        {
	width: auto;
	margin-right: auto;
	margin-left: auto;
	height: 50px;
	text-align: center;
	background-color: #004098;
	background-repeat: repeat-x;
	background-position: bottom;
	background-attachment: scroll;
}
/* CSS Document */
#header3 {
	height: 137px;
	width: auto;
	background-image: url(header_ito.png);
	background-repeat: no-repeat;
	background-position: center top;
	padding: 0px;
	margin-top: 0px;
	margin-right: auto;
	margin-bottom: 0px;
	margin-left: auto;
}
.header3Short {
	height: auto;
	width: auto;
	background-image: url(header_ito.png);
	background-repeat: repeat-x;
	background-position: center top;
	padding: 0px;
	margin-top: 0px;
	margin-right: auto;
	margin-bottom: 0px;
	margin-left: auto;
}
.seisakuCopy {
	padding-top: 10px;
	font-family: "ヒラギノ角ゴ Pro W3", "Hiragino Kaku Gothic Pro", "メイリオ", Meiryo, Osaka, "ＭＳ Ｐゴシック", "MS PGothic", sans-serif;
	font-size: 16px;
	line-height: 20px;
	padding-left: 50px;
	padding-right: 50px;
}
.seisakuCopykoudou {
	font-family: "ヒラギノ角ゴ Pro W3", "Hiragino Kaku Gothic Pro", "メイリオ", Meiryo, Osaka, "ＭＳ Ｐゴシック", "MS PGothic", sans-serif;
	font-size: 16px;
	line-height: 25px;
	letter-spacing: 0.1em;
	white-space: normal;
}
.seisakuCopykoudou3tume {
	font-family: "ヒラギノ角ゴ Pro W3", "Hiragino Kaku Gothic Pro", "メイリオ", Meiryo, Osaka, "ＭＳ Ｐゴシック", "MS PGothic", sans-serif;
	font-size: 16px;
	line-height: 4px;
	letter-spacing: 0.1em;
	white-space: normal;
}
.seisakuCopykoudou2bold {
	font-family: "ヒラギノ角ゴ Pro W3", "Hiragino Kaku Gothic Pro", "メイリオ", Meiryo, Osaka, "ＭＳ Ｐゴシック", "MS PGothic", sans-serif;
	font-size: 16px;
	line-height: 30px;
	letter-spacing: 0.1em;
	white-space: normal;
	color: #004EA2;
	font-weight: bold;
}
.seisakuCopykoudou2gyou {
	font-family: "ヒラギノ角ゴ Pro W3", "Hiragino Kaku Gothic Pro", "メイリオ", Meiryo, Osaka, "ＭＳ Ｐゴシック", "MS PGothic", sans-serif;
	font-size: 16px;
	line-height: 16px;
	letter-spacing: 0.1em;
	white-space: normal;
	color: #004EA2;
	font-weight: bold;
}
.katudouhoukoku {
	padding-top: 10px;
	font-family: "ヒラギノ角ゴ Pro W3", "Hiragino Kaku Gothic Pro", "メイリオ", Meiryo, Osaka, "ＭＳ Ｐゴシック", "MS PGothic", sans-serif;
	font-size: 15px;
	line-height: 20px;
	padding-left: 50px;
}
.seisakuCopy2 {
	padding-top: 10px;
	font-family: "ヒラギノ角ゴ Pro W3", "Hiragino Kaku Gothic Pro", "メイリオ", Meiryo, Osaka, "ＭＳ Ｐゴシック", "MS PGothic", sans-serif;
	font-size: 16px;
	line-height: 22px;
	padding-left: 50px;
	padding-right: 50px;
	letter-spacing: 0.03em;
}
.katudoumidasi {
	font-family: "ヒラギノ角ゴ Pro W3", "Hiragino Kaku Gothic Pro", "メイリオ", Meiryo, Osaka, "ＭＳ Ｐゴシック", "MS PGothic", sans-serif;
	font-size: 18px;
	font-weight: bold;
	letter-spacing: 0.2em;
}
.katudoumidasi2aki {
	font-family: "ヒラギノ角ゴ Pro W3", "Hiragino Kaku Gothic Pro", "メイリオ", Meiryo, Osaka, "ＭＳ Ｐゴシック", "MS PGothic", sans-serif;
	font-size: 22px;
	font-weight: bold;
	letter-spacing: 0.2em;
	line-height: 35px;
}
.upimg {
	padding-bottom: 5px;
	padding-right: 5px;
}
.mintyoutai {
	font-family: "ヒラギノ角ゴ Pro W3", "Hiragino Kaku Gothic Pro", "メイリオ", Meiryo, Osaka, "ＭＳ Ｐゴシック", "MS PGothic", sans-serif;
	font-size: 15px;
	line-height: 24px;
	color: #000;
	letter-spacing: 0.02em;
}
.profileCopy {
	font-family: "ヒラギノ角ゴ Pro W3", "Hiragino Kaku Gothic Pro", "メイリオ", Meiryo, Osaka, "ＭＳ Ｐゴシック", "MS PGothic", sans-serif;
	font-size: 17px;
	line-height: 30px;
	color: #000;
	letter-spacing: 0.02em;
}
.mintyoutai2gyoukan {
	font-family: "ヒラギノ角ゴ Pro W3", "Hiragino Kaku Gothic Pro", "メイリオ", Meiryo, Osaka, "ＭＳ Ｐゴシック", "MS PGothic", sans-serif;
	font-size: 15px;
	line-height: 20px;
	color: #000;
	letter-spacing: 0.02em;
}
.Pcomment {
	font-size: 15px;
	line-height: 26px;
	color: #000;
	width: auto;
	font-family: "ヒラギノ角ゴ Pro W3", "Hiragino Kaku Gothic Pro", "メイリオ", Meiryo, Osaka, "ＭＳ Ｐゴシック", "MS PGothic", sans-serif;
}
.waku_seisaku {
	height: auto;
	width: 800px;
	border: 2px dotted #000;
	padding: 10px;
	background-color: #FFF9E3;
}
.icon {
	padding-top: 20px;
	float: right;
	padding-left: 14px;
}
.icon2 {
	float: left;
	padding-right: 5px;
}
.koudouryoku {
	padding-top: 14px;
	float: right;
	padding-left: 4px;
	padding-bottom: 0px;
	padding-right: 0px;
}
.caption2 {
	font-family: "ヒラギノ角ゴ Pro W3", "Hiragino Kaku Gothic Pro", "メイリオ", Meiryo, Osaka, "ＭＳ Ｐゴシック", "MS PGothic", sans-serif;
	font-size: 15px;
	line-height: 20px;
}
.PhotoCaption {
	padding-bottom: 10px;
}
.photoimage {
	float: left;
	padding-right: 20px;
}
.itoseisaku {
	color: #000000;
	font-family: "ヒラギノ角ゴ Pro W3", "Hiragino Kaku Gothic Pro", "メイリオ", Meiryo, Osaka, "ＭＳ Ｐゴシック", "MS PGothic", sans-serif;
	font-size: 20px;
	line-height: 7mm;
}
.midasifontBOLD {
	font-family: "ヒラギノ角ゴ Pro W3", "Hiragino Kaku Gothic Pro", "メイリオ", Meiryo, Osaka, "ＭＳ Ｐゴシック", "MS PGothic", sans-serif;
	font-size: 18px;
	color: #000;
	line-height: 25px;
	font-weight: bold;
	background-image: url(policy_image/obi_koudou.png);
	background-repeat: no-repeat;
}
img {
	text-decoration: none;
	border-top-width: 0px;
	border-right-width: 0px;
	border-bottom-width: 0px;
	border-left-width: 0px;
	border-top-style: none;
	border-right-style: none;
	border-bottom-style: none;
	border-left-style: none;
}