CSS Reset，意为重置默认样式。HTML中绝大部分标签元素在网页显示中都有一个默认属性值，通常为了避免重复定义元素样式，需要进行重置默认样式（CSS Reset）。举几个例子：1.淘宝（CSS Reset）：html {overflow-x:auto;overflow-y:scroll;}body, dl, dt, dd, ul, ol, li, pre, form, fieldset, input, p, blockquote, th, td {font-weight:400;margin:0;padding:0;}h1, h2, h3, h4, h4, h5 {margin:0;padding:0;}body {background-color:#FFFFFF;color:#666666;font-family:Helvetica,Arial,sans-serif;font-size:12px;padding:0 10px;text-align:left;}select {font-size:12px;}table {border-collapse:collapse;}fieldset, img {border:0 none;}fieldset {margin:0;padding:0;}fieldset p {margin:0;padding:0 0 0 8px;}legend {display:none;}address, caption, em, strong, th, i {font-style:normal;font-weight:400;}table caption {margin-left:-1px;}hr {border-bottom:1px solid #FFFFFF;border-top:1px solid #E4E4E4;border-width:1px 0;clear:both;height:2px;margin:5px 0;overflow:hidden;}ol, ul {list-style-image:none;list-style-position:outside;list-style-type:none;}caption, th {text-align:left;}q:before, q:after, blockquote:before, blockquote:after {content:””;}2.百度（CSS Reset）：body {font-family:arial,helvetica,sans-serif;font-size:13px;font-size-adjust:none;font-stretch:normal;font-style:normal;font-variant:normal;font-weight:normal;line-height:1.4;text-align:center;}body, ul, ol, dl, dd, h1, h2, h3, h4, h5, h6, p, form, fieldset, legend, input, textarea, select, button, th, td {margin:0;padding:0;}h1, h2, h3, h4, h5, h6 {font-size:100%;font-weight:normal;}table {font-size:inherit;}input, select {font-family:arial,helvetica,clean,sans-serif;font-size:100%;font-size-adjust:none;font-stretch:normal;font-style:normal;font-variant:normal;font-weight:normal;line-height:normal;}button {overflow:visible;}th, em, strong, b, address, cite {font-style:normal;font-weight:normal;}li {list-style-image:none;list-style-position:outside;list-style-type:none;}img, fieldset {border:0 none;}ins {text-decoration:none;}3.《超越css》（CSS Reset）：/* Normalizes margin,padding */body,div,dl,dt,dd,ul,ol,li,h1,h2,h3,h4,h5,h6,pre,form,fieldset,input,p,blockquote,th,td { margin:0;padding:0}/* Normalizes font-size for headers */h1,h2,h3,h4,h5,h6 { font-size:100%}/* Removes list-style from lists */ol,ul { list-style:none }/* Normalizes font-size and font-weight to normal */address,caption,cite,code,dfn,em,strong,th,var { font-size:normal; font-weight:normal }/* Removes list-style from lists */table { border-collapse:collapse; border-spacing:0 }/* Removes border from fieldset and img */fieldset,img { border:0 }/* Left-aligns text in caption and th */caption,th { text-align:left }/* Removes quotation marks from q */q:before,q:after { content:”}4.Eric Meyer（CSS Reset）——推荐：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, font, 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 {margin: 0;padding: 0;border: 0;outline: 0;font-size: 100%;vertical-align: baseline;background: transparent;}body {line-height: 1;}ol, ul {list-style: none;}blockquote, q {quotes: none;}blockquote:before, blockquote:after,q:before, q:after {content: ”;content: none;}/* remember to define focus styles! */:focus {outline: 0;}/* remember to highlight inserts somehow! */ins {text-decoration: none;}del {text-decoration: line-through;}/* tables still need ‘cellspacing=”0″‘ in the markup */table {border-collapse: collapse;border-spacing: 0;}5.YUI（CSS Reset）：body,div,dl,dt,dd,ul,ol,li,h1,h2,h3,h4,h5,h6,pre,form,fieldset,input,textarea,p,blockquote,th,td {margin:0;padding:0;}table {border-collapse:collapse;border-spacing:0;}fieldset,img {border:0;}address,caption,cite,code,dfn,em,strong,th,var {font-style:normal;font-weight:normal;}ol,ul {list-style:none;}caption,th {text-align:left;}h1,h2,h3,h4,h5,h6 {font-size:100%;font-weight:normal;}q:before,q:after {content:”;}abbr,acronym { border:0;}

以上来自 Eason_Severus 的CSDN 博客 

CSS Reset 2.0标准

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;}