css reset 为了解决不同浏览器对不同标签的margin和padding默认值不一样

html {
font-family: sans-serif;
-webkit-text-size-adjust: 100%;
-ms-text-size-adjust: 100%
}

body {
margin: 0
}

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

audio, canvas, progress, video {
display: inline-block;
vertical-align: baseline
}

audio:not([controls]) {
display: none;
height: 0
}

[hidden], template {
display: none
}

a {
background-color: transparent
}

a:active, a:hover {
outline: 0
}

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

b, strong {
font-weight: 700
}

dfn {
font-style: italic
}

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

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

small {
font-size: 80%
}

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

sup {
top: -.5em
}

sub {
bottom: -.25em
}

img {
border: 0
}

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

figure {
margin: 1em 40px
}

hr {
height: 0;
-webkit-box-sizing: content-box;
-moz-box-sizing: content-box;
box-sizing: content-box
}

pre {
overflow: auto
}

code, kbd, pre, samp {
font-family: monospace, monospace;
font-size: 1em
}

button, input, optgroup, select, textarea {
margin: 0;
font: inherit;
color: inherit
}

button {
overflow: visible
}

button, select {
text-transform: none
}

button, html input[type=button], input[type=reset], input[type=submit] {
-webkit-appearance: button;
cursor: pointer
}

button[disabled], html input[disabled] {
cursor: default
}

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

input {
line-height: normal
}

input[type=checkbox], input[type=radio] {
-webkit-box-sizing: border-box;
-moz-box-sizing: border-box;
box-sizing: border-box;
padding: 0
}

input[type=number]::-webkit-inner-spin-button, input[type=number]::-webkit-outer-spin-button {
height: auto
}

input[type=search] {
-webkit-box-sizing: content-box;
-moz-box-sizing: content-box;
box-sizing: content-box;
-webkit-appearance: textfield
}

input[type=search]::-webkit-search-cancel-button, input[type=search]::-webkit-search-decoration {
-webkit-appearance: none
}

fieldset {
padding: .35em .625em .75em;
margin: 0 2px;
border: 1px solid silver
}

legend {
padding: 0;
border: 0
}

textarea {
overflow: auto
}

optgroup {
font-weight: 700
}

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

td, th {
padding: 0
}