.site-header {
  background: #fff;
  border-bottom: 1px solid #e5e5e5;
}
.site-header .container {
  max-width: none;
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-align: center;
      -ms-flex-align: center;
          align-items: center;
  -webkit-box-pack: justify;
      -ms-flex-pack: justify;
          justify-content: space-between;
  padding: 12px 16px;
}
.site-nav ul {
  list-style: none;
  margin: 0;
  padding: 0;
}
.site-nav li {
  float: left;
  margin-right: 16px;
}
.site-nav li:last-child {
  margin-right: 0;
}

/* 现代浏览器升级为 flex */
@supports (display: flex) {
  .site-nav ul {
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -webkit-box-align: center;
        -ms-flex-align: center;
            align-items: center;
  }
  .site-nav li {
    float: none;
  }
}