* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  width: 100%;
}
body {
  min-width: 375px;
  margin: 0 auto;
  max-width: 1900px;
}
section {
  max-width: 100%;
}
/* header 页首 */
.nav_header {
  background-color: #29293a;
  min-height: 80px;
}
a {
  text-decoration: none;
}
a:hover {
  text-decoration: none;
}
li {
  list-style-type: none;
  display: inline;
}
.header_div ul li {
  margin-left: 20px;
}
.header_div ul li a {
  color: #fff;
  font-size: 16px;
  padding: 20px;
}
.header_div ul li a:hover {
  background-color: #d18e00;
}


/* footer 页尾 */
footer {
  background-color: #29293a;
  color: #fff;
  padding-top: 0.7%;
  padding-bottom: 1.3%;
}