html {
  overflow: hidden;
  height: 100%;
  scroll-behavior: smooth;
  -webkit-overflow-scrolling: touch;
}
::selection {
  background: #02789E;
  color: #7fffff;
}
body {
  background: #014B76;
  height: 100%;
  color: white;
  margin: 0;
  font-family: "Segoe UI", "冬青黑体简体中文", "Hiragino Sans GB", "微软雅黑 Light", "微软雅黑", "MSYahei";
}
a {
  text-decoration: none;
  color: white;
  color: #BCDCF1;
}
a:hover,.span-sublogo:hover,.span-logo:hover {
  text-shadow: 0 0 1em #FFFF80;
  color: #FFFFFF;
}
.background {
  position: fixed;
  height: 100%;
  width: 100%;
}
.top-content {
  width: 100%;
  min-width: 960px;
  text-align: center;
  position: relative;
  z-index: 100;
  top:50%;
  transform: translate(0, -50%);
  -webkit-transform: translate(0, -50%);
}
.center {
  text-align: center;
}
.span-logo {
  font-size: 4rem;
  color: white;
  text-shadow: 0 0 0.1em #0280CB;
  margin-bottom: 10px;
}
.span-logo::selection {
  background: none;
  color: white;
}
.span-logo img{
  max-height:150px;
}
.span-sublogo {
  font-size: 1em;
  color: white;
  text-shadow: 0 0 0.1em #0280CB;
  margin: 1em auto;
}
.nav {
/*  margin-left: 50%;
  transform: translate(-50%, -50%);
  -webkit-transform: translate(-50%, -50%);*/
  overflow: hidden;
}
.nav a {
  display:inline-block;
  font-size: 1em;
  margin: 1em 20px 0;
  width: 180px;
  height: 50px;
  background: #1ba1f1;
  text-align: center;
  line-height: 50px;
  border-radius: 5px;
  color: #FFFFFF;
}
.about {
  margin-top: 2.5em;
}
.hide {
  display: none;
}
.section {
  height: 100%;
}
.main-content {
  position: relative;
  top: 10%;
  left: 20%;
  width: 60%;
}
@media only screen and (max-width:750px){
  html{
    overflow: auto
  }
  #background canvas{
    width: 100%
  }
  .top-content{
    min-width: auto;
    top: 0;
    -webkit-transform: translate(0, 0);
  }
  .section.now{
    padding-top: 20px;
  }
  .span-logo{
    font-size: 2rem
  }
  html,body,.section{
    height: auto
  }
}