Resetting the Browser style sheet

The browser has a default style sheet, and if you do not neutralize it, you will be adding your styles on top of its styles. Worse, different browsers can have different style sheets, and individuals can personalize the browser’s style sheet. An example: Safari’s default style sheet. To counter this we implement a css reset. There are two to choose from.

The first is by Eric Meyer, who created the first popular reset in 2007, and recently released this second version:

/* http://meyerweb.com/eric/tools/css/reset/
   v2.0 | 20110126
   License: none (public domain)
*/

html, body, div, span, applet, object, iframe,
h1, h2, h3, h4, h5, h6, p, blockquote, pre,
a, abbr, acronym, address, big, cite, code,
del, dfn, em, img, ins, kbd, q, s, samp,
small, strike, strong, sub, sup, tt, var,
b, u, i, center,
dl, dt, dd, ol, ul, li,
fieldset, form, label, legend,
table, caption, tbody, tfoot, thead, tr, th, td,
article, aside, canvas, details, embed,
figure, figcaption, footer, header, hgroup,
menu, nav, output, ruby, section, summary,
time, mark, audio, video {
margin: 0;
padding: 0;
border: 0;
font-size: 100%;
font: inherit;
vertical-align: baseline;
}
/* HTML5 display-role reset for older browsers */
article, aside, details, figcaption, figure,
footer, header, hgroup, menu, nav, section {
display: block;
}
body {
line-height: 1;
}
ol, ul {
list-style: none;
}
blockquote, q {
quotes: none;
}
blockquote:before, blockquote:after,
q:before, q:after {
content: '';
content: none;
}
table {
border-collapse: collapse;
border-spacing: 0;
}

The second reset is called Normalize. It is a more nuanced approach that tries to do as little as possible and attempts to harmonize the browser defaults instead:

/*! normalize.css 2011-09-22T17:42 UTC - http://github.com/necolas/normalize.css */

/* =============================================================================
   HTML5 display definitions
   ========================================================================== */

/*
 * Corrects block display not defined in IE6/7/8/9 & FF3
 */

article,
aside,
details,
figcaption,
figure,
footer,
header,
hgroup,
nav,
section {
    display: block;
}

/*
 * Corrects inline-block display not defined in IE6/7/8/9 & FF3
 */

audio,
canvas,
video {
    display: inline-block;
    *display: inline;
    *zoom: 1;
}

/*
 * Prevents modern browsers from displaying 'audio' without controls
 */

audio:not([controls]) {
    display: none;
}

/*
 * Addresses styling for 'hidden' attribute not present in IE7/8/9, FF3, S4
 * Known issue: no IE6 support
 */

[hidden] {
    display: none;
}


/* =============================================================================
   Base
   ========================================================================== */

/*
 * 1. Corrects text resizing oddly in IE6/7 when body font-size is set using em units
 *    http://clagnut.com/blog/348/#c790
 * 2. Keeps page centred in all browsers regardless of content height
 * 3. Prevents iOS text size adjust after orientation change, without disabling user zoom
 *    www.456bereastreet.com/archive/201012/controlling_text_size_in_safari_for_ios_without_disabling_user_zoom/
 */

html {
    font-size: 100%; /* 1 */
    overflow-y: scroll; /* 2 */
    -webkit-text-size-adjust: 100%; /* 3 */
    -ms-text-size-adjust: 100%; /* 3 */
}

/*
 * Addresses margins handled incorrectly in IE6/7
 */

body {
    margin: 0;
}

/*
 * Addresses font-family inconsistency between 'textarea' and other form elements.
 */

body,
button,
input,
select,
textarea {
    font-family: sans-serif;
}


/* =============================================================================
   Links
   ========================================================================== */

a {
    color: #00e;
}

a:visited {
    color: #551a8b;
}

/*
 * Addresses outline displayed oddly in Chrome
 */

a:focus {
    outline: thin dotted;
}

/*
 * Improves readability when focused and also mouse hovered in all browsers
 * people.opera.com/patrickl/experiments/keyboard/test
 */

a:hover,
a:active {
    outline: 0;
}


/* =============================================================================
   Typography
   ========================================================================== */

/*
 * Addresses styling not present in IE7/8/9, S5, Chrome
 */

abbr[title] {
    border-bottom: 1px dotted;
}

/*
 * Addresses style set to 'bolder' in FF3/4, S4/5, Chrome
*/

b,
strong {
    font-weight: bold;
}

blockquote {
    margin: 1em 40px;
}

/*
 * Addresses styling not present in S5, Chrome
 */

dfn {
    font-style: italic;
}

/*
 * Addresses styling not present in IE6/7/8/9
 */

mark {
    background: #ff0;
    color: #000;
}

/*
 * Corrects font family set oddly in IE6, S4/5, Chrome
 * en.wikipedia.org/wiki/User:Davidgothberg/Test59
 */

pre,
code,
kbd,
samp {
    font-family: monospace, serif;
    _font-family: 'courier new', monospace;
    font-size: 1em;
}

/*
 * Improves readability of pre-formatted text in all browsers
 */

pre {
    white-space: pre;
    white-space: pre-wrap;
    word-wrap: break-word;
}

/*
 * 1. Addresses CSS quotes not supported in IE6/7
 * 2. Addresses quote property not supported in S4
 */

/* 1 */

q {
    quotes: none;
}

/* 2 */

q:before,
q:after {
    content: '';
    content: none;
}

small {
    font-size: 75%;
}

/*
 * Prevents sub and sup affecting line-height in all browsers
 * gist.github.com/413930
 */

sub,
sup {
    font-size: 75%;
    line-height: 0;
    position: relative;
    vertical-align: baseline;
}

sup {
    top: -0.5em;
}

sub {
    bottom: -0.25em;
}


/* =============================================================================
   Lists
   ========================================================================== */

ul,
ol {
    margin: 1em 0;
    padding: 0 0 0 40px;
}

dd {
    margin: 0 0 0 40px;
}

nav ul,
nav ol {
    list-style: none;
    list-style-image: none;
}


/* =============================================================================
   Embedded content
   ========================================================================== */

/*
 * 1. Removes border when inside 'a' element in IE6/7/8/9, FF3
 * 2. Improves image quality when scaled in IE7
 *    code.flickr.com/blog/2008/11/12/on-ui-quality-the-little-things-client-side-image-resizing/
 */

img {
    border: 0; /* 1 */
    -ms-interpolation-mode: bicubic; /* 2 */
}

/*
 * Corrects overflow displayed oddly in IE9
 */

svg:not(:root) {
    overflow: hidden;
}


/* =============================================================================
   Figures
   ========================================================================== */

/*
 * Addresses margin not present in IE6/7/8/9, S5, O11
 */

figure {
    margin: 0;
}


/* =============================================================================
   Forms
   ========================================================================== */

/*
 * Corrects margin displayed oddly in IE6/7
 */

form {
    margin: 0;
}

/*
 * Define consistent border, margin, and padding
 */

fieldset {
    border: 1px solid #c0c0c0;
    margin: 0 2px;
    padding: 0.35em 0.625em 0.75em;
}

/*
 * 1. Corrects color not being inherited in IE6/7/8/9
 * 2. Corrects alignment displayed oddly in IE6/7
 */

legend {
    border: 0; /* 1 */
    *margin-left: -7px; /* 2 */
}

/*
 * 1. Corrects font size not being inherited in all browsers
 * 2. Addresses margins set differently in IE6/7, FF3/4, S5, Chrome
 * 3. Improves appearance and consistency in all browsers
 */

button,
input,
select,
textarea {
    font-size: 100%; /* 1 */
    margin: 0; /* 2 */
    vertical-align: baseline; /* 3 */
    *vertical-align: middle; /* 3 */
}

/*
 * Addresses FF3/4 setting line-height on 'input' using !important in the UA stylesheet
 */

button,
input {
    line-height: normal; /* 1 */
}

/*
 * 1. Improves usability and consistency of cursor style between image-type 'input' and others
 * 2. Corrects inability to style clickable 'input' types in iOS
 * 3. Corrects inner spacing displayed oddly in IE7 without effecting normal text inputs
 *    Known issue: inner spacing remains in IE6
 */

button,
input[type="button"],
input[type="reset"],
input[type="submit"] {
    cursor: pointer; /* 1 */
    -webkit-appearance: button; /* 2 */
    *overflow: visible;  /* 3 */
}

/*
 * 1. Addresses box sizing set to content-box in IE8/9
 * 2. Addresses excess padding in IE8/9
 */

input[type="checkbox"],
input[type="radio"] {
    box-sizing: border-box; /* 1 */
    padding: 0; /* 2 */
}

/*
 * 1. Addresses appearance set to searchfield in S5, Chrome
 * 2. Addresses box sizing set to border-box in S5, Chrome (include -moz to future-proof)
 */

input[type="search"] {
    -webkit-appearance: textfield; /* 1 */
    -moz-box-sizing: content-box;
    -webkit-box-sizing: content-box; /* 2 */
    box-sizing: content-box;
}

/*
 * Corrects inner padding displayed oddly in S5, Chrome on OSX
 */

input[type="search"]::-webkit-search-decoration {
    -webkit-appearance: none;
}

/*
 * Corrects inner padding and border displayed oddly in FF3/4
 * www.sitepen.com/blog/2008/05/14/the-devils-in-the-details-fixing-dojos-toolbar-buttons/
 */

button::-moz-focus-inner,
input::-moz-focus-inner {
    border: 0;
    padding: 0;
}

/*
 * 1. Removes default vertical scrollbar in IE6/7/8/9
 * 2. Improves readability and alignment in all browsers
 */

textarea {
    overflow: auto; /* 1 */
    vertical-align: top; /* 2 */
}


/* =============================================================================
   Tables
   ========================================================================== */

/*
 * Remove most spacing between table cells
 */

table {
    border-collapse: collapse;
    border-spacing: 0;
}