header {
 position: absolute;
 top: 20px;
 left: 0;
 padding: 0 100px;
 background: #fff;
 width: 100%;
 box-sizing: border-box;
 z-index: 99999999;
}

header .logo {
 height: 70px;
 line-height: 30px;
 font-size: 24px;
 float: left;
 font-weight: bold;
}

header .logo img{width:85%;}

header nav {
 float: right;
}

header nav ul {
 margin: 0;
 padding: 0;
 display: flex;
 list-style: none;
}

header nav ul li ul {
 list-style: none;
 margin-left: 0;
}

header nav ul li {
 list-style: none;
 position: relative;
}

header nav a {
 display: inline-block;
 overflow: visible;
}

header nav ul li.sub-menu:before {
 content: none;
 display: none;
}

header nav ul li.active.sub-menu:before {
 content: none;
 display: none;
}

header nav ul li ul {
 position: absolute;
 left: 0;
 background: #fff;
 display: none;
 box-shadow: 0 4px 12px rgba(0,0,0,0.08);
}

header nav ul li.active ul {
 display: block;
}

/* 桌面端：悬停展开，移开自动收起 */
@media (min-width: 992px) {
 header nav ul li.sub-menu:hover > ul,
 header nav ul li.sub-menu:focus-within > ul {
  display: block;
 }

 header nav ul li.sub-menu:hover:before,
 header nav ul li.active.sub-menu:before {
  content: none;
  display: none;
 }
}

header nav ul li ul li {
 display: block;
 width: 270px;
}

header nav ul li a {
 height: 50px;
 line-height: 50px;
 padding: 0 25px;
 color: #262626;
 text-decoration: none;
 display: block;
 font-size: 13px;
 letter-spacing: 1px;
}

.menu-toggle {
 color: #8c665d;
 float: right;
 line-height: 50px;
 font-size: 24px;
 cursor: pointer;
 display: none;
 margin-top: 10px;
}

@media (max-width: 991px) {
 header {
  padding: 0 20px;
 }

 .menu-toggle {
  display: block;
 }

 header nav {
  position: absolute;
  width: 100%;
  height: calc(100vh - 50px);
  background: #e4d9d2;
  top: 50px;
  left: -100%;
  transition: 0.5s;
  overflow-y: auto;
 }

 header nav.active {
  left: 0;
 }

 header nav ul {
  display: block;
  text-align: center;
 }

 header nav ul li a {
  border-bottom: 1px solid rgba(255,255,255,.2);
 }

 header nav ul li.active ul {
  position: relative;
  background: #ded0c8;
 }

 header nav ul li ul li {
  width: 100%;
 }
}