body {
color: #333;
font-size: 16px;
font-family: PingFangSC-Regular, Microsoft YaHei, Helvetica;
}

body, div, form, h1, h2, h3, h4, h5, h6, html, li, p, ul {
margin: 0;
padding: 0;
list-style: none;
box-sizing: border-box;
}
body {
font-family: -apple-system, BlinkMacSystemFont, Helvetica Neue, Helvetica, Segoe UI, Arial, Roboto, PingFang SC, miui, Hiragino Sans GB, Microsoft Yahei, sans-serif;
}
* {
box-sizing: border-box;
}
user agent stylesheet
body {
display: block;
}
html {
line-height: 1.15;
-webkit-text-size-adjust: 100%;
}

html {
font-size: 13.33333vw;
}
html {
-webkit-tap-highlight-color: transparent;
}


h1, h2, h3, h4, h5, h6 {
  font-family: -apple-system,BlinkMacSystemFont,segoe ui,Roboto,helvetica neue,Arial,noto sans,sans-serif,apple color emoji,segoe ui emoji,segoe ui symbol,noto color emoji;
}

img {
  border: none;
}

a:link {
  color: #666;
  text-decoration: none;
}

a:visited {
  color: #666;
  text-decoration: none;
}

a:hover {
  color: #333;
  text-decoration: none;
}

a:active {
  color: #666;
  text-decoration: none;
}

.clear {
  clear: both;
}

i, s {
  font-style: normal;
}

button, textarea, input, select {
  outline: none;
}

::-webkit-input-placeholder {
  /* WebKit browsers */
  color: #ababab;
}

:-moz-placeholder {
  /* Mozilla Firefox 4 to 18 */
  color: #ababab;
}

::-moz-placeholder {
  /* Mozilla Firefox 19+ */
  color: #ababab;
}

:-ms-input-placeholder {
  /* Internet Explorer 10+ */
  color: #ababab;
}
header{
  width:100%;
  overflow:hidden;
    height: 45px;
  position:fixed;
  left:0;
  top:0;}
main{
	max-width:720px;margin:46px auto;overflow:hidden;}
.top_nav{
	max-width:720px;
    height: 45px;
    border-bottom: 1px solid #ebedf0;
    justify-content: space-between;
    line-height: 45px;
    padding: 0 10px;
    box-sizing: border-box;
	text-align:center;
	z-index:999999;
	background:#fff;
	margin:0 auto;
	
}