Default style sheet for HTML 4

答案：This appendix is informative, not normative. 

This style sheet describes the typical formatting of all HTML 4 ([HTML4]) elements based on extensive research into current UA practice. Developers are encouraged to use it as a default style sheet in their implementations.  

The full presentation of some HTML elements cannot be expressed in CSS 2.1, including replaced elements ("img", "object"), scripting elements ("script", "applet"), form control elements, and frame elements.  

For other elements, the legacy presentation can be described in CSS but the solution removes the element. For example, the FONT element can be replaced by attaching CSS declarations to other elements (e.g., DIV). Likewise, legacy presentation of presentational attributes (e.g., the "border" attribute on TABLE) can be described in CSS, but the markup in the source document must be changed.  

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 } 
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          { 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" } 
:before, :after { 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 } 
} 

上一个：Lesson02_04 表单标签(2)
下一个：用好href的target属性