Sample "UA" default stylesheets for HTML 2.0 and HTML 4.0

UA = User-Agent = HTTP Client = Web Browser

Take a look at the sample default stylesheets for HTML 2.0 and HTML 4.0 listed in the Appendices of the CSS1 and CSS2 Recommendations.

HTML 4 Sample default CSS

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; line-height: 1.12 }
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, pre,
input, object,
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 }
abbr, acronym   { font-variant: small-caps; letter-spacing: 0.1em }
: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 }
}

HTML 2 Sample default CSS

BODY {
  margin: 1em;
  font-family: serif;
  line-height: 1.1;
  background: white;
  color: black;
}

H1, H2, H3, H4, H5, H6, P, UL, OL, DIR, MENU, DIV,
DT, DD, ADDRESS, BLOCKQUOTE, PRE, BR, HR, FORM, DL {
  display: block }

B, STRONG, I, EM, CITE, VAR, TT, CODE, KBD, SAMP,
IMG, SPAN { display: inline }

LI { display: list-item }

H1, H2, H3, H4 { margin-top: 1em; margin-bottom: 1em }
H5, H6 { margin-top: 1em }
H1 { text-align: center }
H1, H2, H4, H6 { font-weight: bold }
H3, H5 { font-style: italic }

H1 { font-size: xx-large }
H2 { font-size: x-large }
H3 { font-size: large }

B, STRONG { font-weight: bolder }  /* relative to the parent */
I, CITE, EM, VAR, ADDRESS, BLOCKQUOTE { font-style: italic }
PRE, TT, CODE, KBD, SAMP { font-family: monospace }

PRE { white-space: pre }

ADDRESS { margin-left: 3em }
BLOCKQUOTE { margin-left: 3em; margin-right: 3em }

UL, DIR { list-style: disc }
OL { list-style: decimal }
MENU { margin: 0 }              /* tight formatting */
LI { margin-left: 3em }

DT { margin-bottom: 0 }
DD { margin-top: 0; margin-left: 3em }

HR { border-top: solid }        /* 'border-bottom' could also have been used */

A:link { color: blue }          /* unvisited link */
A:visited { color: red }        /* visited links */
A:active { color: lime }        /* active links */

/* setting the anchor border around IMG elements
   requires contextual selectors */

A:link IMG { border: 2px solid blue }
A:visited IMG { border: 2px solid red }
A:active IMG { border: 2px solid lime }