* {
  padding: 0;
  margin: 0;
  box-sizing: border-box;
  font-family: Source Han Sans-Normal, Source Han Sans, Microsoft YaHei, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen-Sans, Ubuntu, Cantarell, "Helvetica Neue", Helvetica, Arial, Microsoft YaHei, sans-serif;
  font-family: Source Han Sans-Normal, Source Han Sans, Microsoft YaHei, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen-Sans, Ubuntu, Cantarell, "Helvetica Neue", Helvetica, Arial, Microsoft YaHei, sans-serif;
}
.mt-center {
  width: 1200px;
  margin: auto;
}
ul {
  list-style: none;
  flex-wrap: wrap;
  padding: 0;
  margin: 0;
}
li {
  list-style-type: none;
}
a {
  text-decoration: none;
  color: inherit;
}
.download-header {
  position: absolute;
  width: 100%;
  height: 80px;
}
input {
  border: none;
  outline: none;
}
/* 应用于竖屏模式的小屏幕手机 */