开始的时候 *{margin:0;padding:0;}，当需要使用边距的时候，就需要还原HTML默认CSS值了。以前一直在找这份 文档，今天偶然在w3上看到了。除了inline和block的定义，主要是要注意 body|h1~h6|blockquote|menu|ul|ol|dd等标签的默认样式（margin和font-size）。这个东 西在你需要还原默认值的时候，比较有用。 详见下面的内容：

html,address,blockquote,body,dd,div,dl,dt,fieldset,form,frame,frameset,h1,h2,h3,h4,h5,h6,noframes,ol,p,ul,center,dir,hr,menu,pre{display:block}

li{display:list-item}

head{display:none}

table{display:table}

tr{display:table-row}

thead{display:table-header-group}

tbody{display:table-row-group}

tfoot{display:table-footer-group}

col{display:table-column}

colgroup{display:table-column-group}

td,th{display:table-cell;}

caption{display:table-caption}

th{font-weight:bolder; text-align:center}

caption{text-align:center}

body{margin:8px; line-height:1.12}

h1{font-size:2em; margin:.67em 0}

h2{font-size:1.5em; margin:.75em 0}

h3{font-size:1.17em; margin:.83em 0}

h4,p,blockquote,ul,fieldset,form,ol,dl,dir,menu{margin:1.12em 0}

h5{font-size:.83em; margin:1.5em 0}

h6{font-size:.75em; margin:1.67em 0}

h1,h2,h3,h4,h5,h6,b,strong{font-weight:bolder}

blockquote{margin-left:40px; margin-right:40px}

i,cite,em,var,address{font-style:italic}

pre,tt,code,kbd,samp{font-family:monospace}

pre{white-space:pre}

button,textarea,input,object,select{display:inline-block;}

big{font-size:1.17em}

small,sub,sup{font-size:.83em}

sub{vertical-align:sub}

sup{vertical-align:super}

table{border-spacing:2px;}

thead,tbody,tfoot{vertical-align:middle}

td,th{vertical-align:inherit}

s,strike,del{text-decoration:line-through}

hr{border:1px inset}

ol,ul,dir,menu,dd{margin-left:40px}

ol{list-style-type:decimal}

ol ul,ul ol,ul ul,ol ol{margin-top:0; margin-bottom:0}

u,ins{text-decoration:underline}

br:before{content:”A”}

:before,:after{white-space:pre-line}

center{text-align:center}

abbr,acronym{font-variant:small-caps; letter-spacing:0.1em}

:link,:visited{text-decoration:underline}

:focus{outline:thin dotted invert}

@media print{

h1{page-break-before:always}

h1,h2,h3,

h4,h5,h6{page-break-after:avoid}

ul,ol,dl{page-break-before:avoid}