html,body {
  width: 100%;
  height: 100%;
  margin: 0;
  padding: 0;
}
#app {
  background: url('../images/background.jpg');
  background-size: 100% 100%;
  position: absolute;
  width: 100%;
  padding-bottom: 177%;
}
#androidButton {
  position: absolute;
  background: url('../images/androidButton.png') 0 0 no-repeat;
  width: 50%;
  padding-bottom: 17.72%;
  margin: 140% 25% 0;
  background-size: 100% 100%;
}
#iosButton {
  position: absolute;
  background: url('../images/iosButton.png') 0 0 no-repeat;
  width: 50%;
  padding-bottom: 17.72%;
  margin: 140% 25% 0;
  background-size: 100% 100%;
}
/* 遮罩 */
#shade {
  width: 100%;
  padding-bottom: 177%;
  background: rgba(0, 0, 0, 0.5);
  position: absolute;
  justify-content: center;
  align-items: center;
  display: -webkit-flex;
  display: flex;
  z-index: 999;
}
#tip {
  display: inline-block;
  width: 100%;
  height: 100%;
  position: absolute;
  right: 0;
  max-width:  500px;
}
.ios_tip {
  background: url('../images/ios_tip.png') 0 0 no-repeat;
  background-size: 100% auto;
  z-index: 1000;
}
.android_tip {
  background: url('../images/android_tip.png') 0 0 no-repeat;
  background-size: 100% auto;
  z-index: 1000;
}
/* @media screen and (min-width: 850px) {
  #androidButton {
    background: url('../images/androidButton.png') 0 0 no-repeat;
    width: 200px;
    padding-bottom: 100px;
    margin: 0 auto;
    background-size: 100% auto;
  }
  #iosButton {
    background: url('../images/iosButton.png') 0 0 no-repeat;
    width: 200px;
    padding-bottom: 100px;
    margin: 0 auto;
    background-size: 100% auto;
  }
} */