整理XIAO-A的css必备

（-）重置样式

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;  outline: none;  -webkit-box-sizing: border-box;  -moz-box-sizing: border-box;  box-sizing: border-box;}html { height: 101%; }body { font-size: 62.5%; line-height: 1; font-family: Arial, Tahoma, sans-serif; }article, aside, details, figcaption, figure, footer, header, hgroup, menu, nav, section { display: block; }ol, ul { list-style: none; }blockquote, q { quotes: none; }blockquote:before, blockquote:after, q:before, q:after { content: ''; content: none; }strong { font-weight: bold; } table { border-collapse: collapse; border-spacing: 0; }img { border: 0; max-width: 100%; }p { font-size: 1.2em; line-height: 1.0em; color: #333; }

说明：

（二）clearfix（经典款）

.clearfix:after { content: "."; display: block; clear: both; visibility: hidden; line-height: 0; height: 0; }.clearfix { display: inline-block; }html[xmlns] .clearfix { display: block; }* html .clearfix { height: 1%; }

说明：

      这个css的原理是经过使用after伪对象,它将在应用clearfix的元素结尾添加content中的内容,也就是一个".",并且把他设置为块级元素(display="block");高度设置为0,clear="both",然后将其内容隐藏掉(visibility="hidden").这样就会撑开此块级元素.