strong,
b {
  font-weight: 500;
}

body {
  padding: 0;
  margin: 0;
  font-family: -apple-system, system-ui, BlinkMacSystemFont, "Helvetica Neue", Helvetica, Arial, "Microsoft YaHei",
    "PingFang SC", "Source Han Sans CN", "Noto Sans CJK SC", sans-serif;
  font-weight: 400;
}

.splite {
  padding-top: 56px;
}

ul {
  list-style: none;
}

a {
  text-decoration: none;
  color: #0469e3;
}

.clear {
  clear: both;
}

.fl {
  float: left;
}

.fr {
  float: right;
}

.bg_pink {
  background-color: #fff2f2;
  padding: 0 4px;
  border-radius: 6px;
}

.nav_bg {
  background-color: #333437;
  position: fixed;
  width: 100%;
  z-index: 999;
}

.color_blue {
  color: #0469e3;
}

.color_black {
  color: #000;
}

.preview {
  background-color: #fff3b8;
  text-align: center;
  padding: 12px;
  margin: 0 auto;
  position: sticky;
  top: 0;
  cursor: pointer;
  z-index: 100;
}

.nav {
  max-width: 1920px;
  min-width: 768px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  top: 0;
  z-index: 999;
  /* border-bottom: 1px solid #e5e5e5; */
  overflow: hidden;
  box-sizing: border-box;
  padding: 0 24px;
}

.menu a:hover {
  opacity: 0.7;
}

.nav .logo {
  width: 180px;
  min-width: 150px;
}

.nav ul {
  display: flex;
  gap: 32px;
  margin: 16px 0;
}

.nav ul li a {
  padding: 16px 16px;
  color: #fff;
  text-wrap: nowrap;
}

/* sitmap */

.footer a {
  text-decoration: none;
  color: inherit;
}

.footer a:hover {
  color: #2697ff;
}

.footer {
  background: #1b1c22;
  color: #cacaca;
  padding: 48px 48px 24px 48px;
}

.footer ul {
  margin: 0 0 24px 0;
}

.footer .sitemap {
  display: flex;
  max-width: 1280px;
  margin: 0 auto;
  font-size: 14px;
  padding: 0px;
}

.footer .sitemap ul {
  padding: 0;
  margin-right: 24px;
  display: flex;
  gap: 48px;
}

.footer .sitemap li {
  list-style: none;
  padding: 6px 0;
  opacity: 0.8;
}

.footer .sitemap p {
  font-size: 12px;
  opacity: 0.7;
}

.footer .copyright {
  font-size: 12px;
  opacity: 0.7;
  max-width: 1280px;
  margin: 0 auto;
  padding: 16px 0;
  border-top: 1px solid #cacaca42;
}

@media screen and (max-width: 500px) {
  .body {
    overflow: hidden;
  }

  .nav {
    flex-direction: column;
    width: 100%;
    min-width: 320px;
    padding: 0;
  }

  .nav .logo {
    min-width: 150px;
    width: 160px;
    box-sizing: border-box;
    padding: 8px;
  }

  .nav ul {
    gap: 0;
    margin: 0;
    width: 100%;
    padding: 0;
    justify-content: space-between;
  }

  .nav ul li a {
    display: block;
    text-align: center;
    font-size: 14px;
    color: #000;
  }

  .nav .menu_bg {
    overflow: auto;
    background-color: #eeeeee;
    width: 100%;
    display: flex;
    justify-content: space-between;
  }

  .splite {
    padding-top: 100px;
  }

  .footer {
    position: relative;
    padding: 16px;
    padding-bottom: 108px;
  }

  .footer .sitemap {
    flex-wrap: wrap;
  }

  .footer .sitemap > div {
    width: 100%;
  }

  .footer .sitemap ul {
    padding: 0;
    display: flex;
    flex-direction: column;
    gap: 0;
    width: 100%;
  }

  .footer ul li a {
    padding: 12px 0;
    display: block;
    width: 100%;
  }
}