* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
html {
  opacity: 0;
  animation: FadeIn .2s forwards;
}
@keyframes FadeIn {
  0% {
    opacity: 0;
  }
  100% {
    opacity: 1;
  }
}
a {
  text-decoration: none;
  -webkit-tap-highlight-color: rgba(0, 0, 0, 0);
}
img {
  display: block;
}

/* 弹性布局 */
.f-jcc-aic {
  display: flex;
  justify-content: center;
  align-items: center;
}
.f-jcc {
  display: flex;
  justify-content: center;
}
.f-aic {
  display: flex;
  align-items: center;
}
.f-jcsb {
  display: flex;
  justify-content: space-between;
}
.f-aife {
  display: flex;
  align-items: flex-end;
}
.f-jcsb-aic {
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.f-dc {
  display: flex;
  flex-direction: column;
}
.f-dc-jcsb {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}
.f-dc-aic {
  display: flex;
  flex-direction: column;
  align-items: center;
}
.f-dc-jcc-aic {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
}
.bg-cover {
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
}
.bg-contain {
  background-size: contain;
  background-position: center;
  background-repeat: no-repeat;
}