html {
  height: 100%;
  width: 100%;
  background: url(../images/bg/back_bg.jpg) no-repeat center top / 100% auto black fixed;
  overflow: hidden;
}

body {
  background-color: rgba(0, 0, 0, 0.5);
  background-size: 100% 100%;
}

body,
#app {
  margin: 0;
  padding: 0;
  width: 100%;
  height: 100%;
  min-width: 600px;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

li {
  list-style: none;
}

#app .app_head {
  width: 100%;
  height: 110px;
  padding: 30px 0 0 56px;
}

#app .app_head>*+* {
  margin-left: 5px;
}

#app .app_head span {
  padding: 0;
  font-size: 38px;
  color: white;
  line-height: 44px;
  vertical-align: top;
}

#app .app_head img {
  height: 44px;
}

.app_bottom {
  position: absolute;
  width: 100%;
  bottom: 30px;
  font-size: 12px;
  color: aliceblue;
  display: flex;
  justify-content: center;
  align-items: center;
}

.app_bottom>div {
  margin-right: 10px;
}

.app_bottom span {
  margin-right: 4px;
}

.app_bottom a {
  text-decoration: none;
  color: white;
}

.app_content {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  height: 600px;
  width: 100%;
  display: flex;
  justify-content: center;
  align-items: center;
}

.app_content>div {
  width: 1000px;
  height: 100%;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.app_content_text .app_content_select {
  position: relative;
  flex: 0 0 500px;
  display: flex;
  align-items: center;
}

.app_content_select .selectBox {
  flex: 0 0 340px;
}

.app_content_select .selectBox ul {
  width: 460px;
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;

}

.app_content_select .selectBox ul li {
  height: 110px;
  width: 200px;
}

@media screen and (max-width: 1500px) {
  .app_content {
    zoom: .8;
  }
}

@media screen and (max-width: 1200px) {
  .app_content {
    zoom: .6;
  }
}

@media screen and (max-height: 800px) {
  .app_content {
    zoom: .8;
    height: 500px;
  }
}