body {
  margin: 0;
  padding: 0;
  --bg-image-mobile: url("./img/bg_mb.jpg"); /* 默认移动端背景 */
  --bg-image-desktop: url("./img/bg_pc.jpg"); /* 默认桌面端背景 */
  display: none;
}
.container {
  text-align: center;
}
#textWrap {
  font-weight: bold;
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  color: rgb(104, 52, 3);
}
#textWrap #title {
  color: #434e73;
}
#logo {
  padding-top: 60px;
}
#logo img {
  height: 100px;
}

#title {
  margin-bottom: 20px;
  font-size: larger;
}
@media (min-width: 768px) {
  body {
    background: var(--bg-image-desktop) no-repeat center center fixed;
    -webkit-background-size: cover;
    -moz-background-size: cover;
    -o-background-size: cover;
    background-size: cover;
  }
  #textWrap {
    margin-top: 40px;
    font-size: x-large;
  }
}
@media (max-width: 767px) {
  body {
    background: var(--bg-image-mobile) no-repeat top center fixed;
    -webkit-background-size: cover;
    -moz-background-size: cover;
    -o-background-size: cover;
    background-size: cover;
  }
  #textWrap {
    margin-top: 60px;
    padding-left: 20px;
    padding-right: 20px;
    line-height: 27px;
    font-size: medium;
  }
}