html {
  height: 100%;
}

body {
  margin: 0;
  min-height: 100%;
  background-color: #ffffff;
  background-size: 100% 100%;
}

/* 手机设备启动图 */
@media (max-width: 767px) {
  @media (prefers-color-scheme: dark) {
    html{
      background: linear-gradient(203.16deg, #404552 -26.47%, #1B1E21 70.03%, #1A1C1F 121.68%);
      body {
        background: linear-gradient(203.16deg, #404552 -26.47%, #1B1E21 70.03%, #1A1C1F 121.68%);
        background-image: url("img/black_logo.png");
        background-position: bottom center;
        background-repeat: no-repeat;
        background-size: 150px;
      }
    }
  }

  @media (prefers-color-scheme: light) {
    body {
      background-color: #EEF7FF;
      background-image: url("img/light_logo.png");
      background-position: bottom center;
      background-repeat: no-repeat;
      background-size: 150px;
    }
  }
}

/* pad和电脑设备启动图 */
@media (min-width: 768px) {
  @media (prefers-color-scheme: dark) {
    html{
      background: linear-gradient(203.16deg, #404552 -26.47%, #1B1E21 70.03%, #1A1C1F 121.68%);
      body {
        background: linear-gradient(203.16deg, #404552 -26.47%, #1B1E21 70.03%, #1A1C1F 121.68%);
        background-image: url("img/black_logo.png");
        background-position: bottom center;
        background-repeat: no-repeat;
        background-size: 200px;
      }
    }
  }

  @media (prefers-color-scheme: light) {
    body {
      background-color: #EEF7FF;
      background-image: url("img/light_logo.png");
      background-position: bottom center;
      background-repeat: no-repeat;
      background-size: 200px;
    }
  }
}

.center {
  margin: 0;
  position: absolute;
  top: 50%;
  left: 50%;
  -ms-transform: translate(-50%, -50%);
  transform: translate(-50%, -50%);
}

.contain {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: contain;
}

.stretch {
  display: block;
  width: 100%;
  height: 100%;
}

.cover {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.bottom {
  position: absolute;
  bottom: 0;
  left: 50%;
  -ms-transform: translate(-50%, 0);
  transform: translate(-50%, 0);
}

.bottomLeft {
  position: absolute;
  bottom: 0;
  left: 0;
}

.bottomRight {
  position: absolute;
  bottom: 0;
  right: 0;
}