HTML CSS equivalency

(these are instructive rather than exhaustive... see below for more thorough listings)

	CSS equivalent	undo
<b>	font-weight: bold;	font-weight: normal;
<i> <em>	font-style: italic;	font-style: normal;
<u>	text-decoration: underline;	text-decoration: none;
<s>	text-decoration: line-through;	text-decoration: none;
<blink>	text-decoration: blink;	text-decoration: none;
<tt>	font-family: monospace;	font-family: serif;
<pre>	white-space: pre; font-family: monospace;	white-space: normal; font-family: serif;
<center>	margin: 0 auto; (NOTE: document must have a valid DOCTYPE, otherwise it won't work in IE)	margin: 0 0;
<del>	text-decoration: line-through;	text-decoration: none;
<q>	`q::before, q::after {content:'"'}`	`q::before, q::after {content:''; content:none}`

<sup>	vertical-align: super; font-size: 75%; (closish?)
<sub>	vertical-align: sub; font-size: 75%; (closish?)

<div> <p>	display: block;
<span>	display: inline;
<table>	display: table;
<td> <th>	display: table-cell;

Browser defaults

Some browsers expose their default .css rules, which is more or less the above list.

Firefox: layout/style/html.css (and quirk.css)

Safari:
file:///System/Library/Frameworks/WebKit.framework/Versions/A/Frameworks/WebCore.framework/Versions/A/Resources/html4.css
file:///System/Library/Frameworks/WebKit.framework/Versions/A/Frameworks/WebCore.framework/Versions/A/Resources/quirks.css

Unified "base"/"reset" .css

Some people have put together a single stylesheet that tries to make all the browsers work as closely as possible 1) to each other, and sometimes 2) to the standard. In the case of #2, they're useful for the above.