* {
  padding: 0;
  margin: 0;
  font-family: "Microsoft YaHei";
  moz-user-select: -moz-none;
  -moz-user-select: none;
  -o-user-select: none;
  -khtml-user-select: none;
  -webkit-user-select: none;
  -ms-user-select: none;
  user-select: none;
}

html {
  width: 100%;
  height: 100%;
  overflow: hidden;
}

body {
  background-image: url(//cdn-file.cdcyber.com/web2/cdcyber/daytab/images/index/bg-2531be46ce.png);
  background-size: content;
  background-position: center;
}

.header {
  width: 100%;
  height: 80px;
  background: #ffffff;
  box-shadow: 0px 3px 6px 1px rgba(0, 0, 0, 0.16);
  overflow: hidden;
}
.header .box {
  width: 1200px;
  height: 100%;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.header .box .nav {
  display: flex;
}
.header .box .nav div {
  margin-left: 54px;
  cursor: pointer;
  font-weight: 400;
  font-size: 14px;
  color: #152646;
}

.main {
  width: 770px;
  padding-top: 135px;
  margin: 0 auto;
  text-align: center;
}
.main .desc {
  height: 135px;
  line-height: 80px;
  text-align: center;
  font-weight: 400;
  font-size: 22px;
  color: #4e5461;
}
.main .list {
  height: 112px;
  display: flex;
  justify-content: space-between;
}
.main .list div {
  width: 174px;
  height: 55px;
  background-size: 522px 55px;
  cursor: pointer;
}
.main .list div.edge {
  background-image: url(//cdn-file.cdcyber.com/web2/cdcyber/daytab/images/index/edge-25376b6c78.png);
}
.main .list div.chrome {
  background-image: url(//cdn-file.cdcyber.com/web2/cdcyber/daytab/images/index/chrome-c70c535d52.png);
}
.main .list div.firefox {
  background-image: url(//cdn-file.cdcyber.com/web2/cdcyber/daytab/images/index/firefox-68fbab51eb.png);
}
.main .list div.pkg {
  background-image: url(//cdn-file.cdcyber.com/web2/cdcyber/daytab/images/index/pkg-3b368ea717.png);
}
.main .list div:hover {
  background-position-x: -174px;
}