CSS styles need to be initialized before writing CSS styles, summarized as follows:
/*CSS Document*/html, body, Div, span,Object, IFRAME,H1, H2, H3, H4, H5, H6, p, blockquote, PRE,ABBR, address, cite, Code,del, DFN, EM, IMG, INS,KBD, q, Samp,smal L, strong, sub, SUP,var, B, I,DL, DT, DD, OL, UL, Li,fieldset, form, label, Legend,table, Caption, tbody, tfoot,thead,tr, Th, td,article, ASID E, canvas, details, figcaption, figure, Footer, Header, Hgroup, menu, nav, section, Summary,time, mark, audio, video { Margin:0; padding:0; border:0; Outline:0; Font-size: -%; Vertical-Align:baseline; Background:transparent; Outline-style:none;/*FF*/}body { line-height:1;} a{margin:0; padding:0; border:0; Font-size: -%; Vertical-Align:baseline; Background:transparent; }a:hover,a:focus{text-Decoration:none; Bblr:expression ( This. onfocus= This. blur ());/*IE*/Outline-style:none;/*FF*/}table {Border-Collapse:collapse; Border-spacing:0;} Input,Select{Vertical-Align:middle;}/*CSS for Clearfix, clear floating*/. clearfix::before,.clearfix::after{content:""; Height:0; Line-height:0; Display:block; Visibility:hidden; Clear:both;}. Clearfix:after{clear:both;}. clearfix{*zoom:1;/*IE/7/6*/}
Summary of CSS style initialization code