css要素のデフォルトスタイル

html, address, blockquote, body, dd, div, dl, dt, fieldset, form, frame, frameset, h1, h2, h3, h4, h5, h6, noframes, ol, p, ul, center, dir, hr, menu, pre {
	display: block;
	unicode-bidi: embed
}
li {
	display: list-item
}
head {
	display: none
}
table {
	display: table
}
tr {
	display: table-row
}
thead {
	display: table-header-group
}
tbody {
	display: table-row-group
}
tfoot {
	display: table-footer-group
}
col {
	display: table-column
}
colgroup {
	display: table-column-group
}
td, th {
	display: table-cell
}
caption {
	display: table-caption
}
th {
	font-weight: bolder;
	text-align: center
}
caption {
	text-align: center
}
body {
	margin: 8px
}
h1 {
	font-size: 2em;
	margin: .67em 0
}
h2 {
	font-size: 1.5em;
	margin: .75em 0
}
h3 {
	font-size: 1.17em;
	margin: .83em 0
}
h4, p, blockquote, ul, fieldset, form, ol, dl, dir, menu {
	margin: 1.12em 0
}
h5 {
	font-size: .83em;
	margin: 1.5em 0
}
h6 {
	font-size: .75em;
	margin: 1.67em 0
}
h1, h2, h3, h4, h5, h6, b, strong {
	font-weight: bolder
}
blockquote {
	margin-left: 40px;
	margin-right: 40px
}
i, cite, em, var, address {
	font-style: italic
}
pre, tt, code, kbd, samp {
	font-family: monospace
}
pre {
	white-space: pre
}
button, textarea, input, select {
	display: inline-block
}
big {
	font-size: 1.17em
}
small, sub, sup {
	font-size: .83em
}
sub {
	vertical-align: sub
}
sup {
	vertical-align: super
}
table {
	border-spacing: 2px;
}
thead, tbody, tfoot {
	vertical-align: middle
}
td, th, tr {
	vertical-align: inherit
}
s, strike, del {
	text-decoration: line-through
}
hr {
	border: 1px inset
}
ol, ul, dir, menu, dd {
	margin-left: 40px
}
ol {
	list-style-type: decimal
}
ol ul, ul ol, ul ul, ol ol {
	margin-top: 0;
	margin-bottom: 0
}
u, ins {
	text-decoration: underline
}
br:before {
	content: "\A";
	white-space: pre-line
}
center {
	text-align: center
}
:link, :visited {
	text-decoration: underline
}
:focus {
	outline: thin dotted invert
} /* Begin bidirectionality settings (do not change) */
BDO[DIR="ltr"] {
	direction: ltr;
	unicode-bidi: bidi-override
}
BDO[DIR="rtl"] {
	direction: rtl;
	unicode-bidi: bidi-override
}
*[DIR="ltr"] {
	direction: ltr;
	unicode-bidi: embed
}
*[DIR="rtl"] {
	direction: rtl;
	unicode-bidi: embed
}

@media print {
h1 {
	page-break-before: always
}
h1, h2, h3, h4, h5, h6 {
	page-break-after: avoid
}
ul, ol, dl {
	page-break-before: avoid
}
}

参考サイト

タグHTML

デフォルトスタイルシート（ブラウザが標準で持っているスタイル設定）について

http://taghtml.com/css/defaultstylesheet.html