Browsers' default CSS for HTML elements
It's different for each browser, so:
- Firefox (Gecko): https://dxr.mozilla.org/mozilla-central/source/layout/style/res/html.css. Or, browse to
resource://gre-resources/and look athtml.css. - Chrome/Safari (WebKit): http://trac.webkit.org/browser/trunk/Source/WebCore/css/html.css
- Chrome (Blink): https://chromium.googlesource.com/chromium/blink/+/master/Source/core/css/html.css
- Internet Explorer (Trident), older versions: http://web.archive.org/web/20170122223926/http://www.iecss.com/
You can also look at the HTML5 Boilerplate stylesheet, which "normalizes the display of a lot of stuff without being a reset in the traditional sense". It also fixes quite a few bugs/inconsistencies.
It's also worth looking at: https://github.com/necolas/normalize.css/blob/master/normalize.css
A GitHub repository of all W3C HTML spec and vendor default CSS stylesheets can be found here
- Default Styles for Gecko / Firefox --
- Default Styles for Internet Explorer --
- Default Styles for Webkit / Safari --
- Default Styles for Blink / Chrome --
- Default Styles for Opera --
- Default Styles for HTML4 (W3C spec) --
- Default Styles for HTML5 (W3C spec) --
Sample, per the default W3C HTML4 spec:
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 }
}
No one has mentioned any source for the CSS defaults in Edge. I looked, and I couldn't find anything authoritative, but I found this stylesheet that looks plausible: https://gist.github.com/jonathantneal/abc52743caa0a019d359ec4ba2ce965b