* {
  box-sizing: border-box;
}

html,
body {
  width: 100%;
  height: 100%;
}

body {
  margin: 0;
  overflow: hidden;
  background: #000;
  font-family: "Microsoft YaHei", "SimHei", sans-serif;
}

.image-page {
  width: 100vw;
  height: 100vh;
  display: grid;
  place-items: center;
  background: #000;
}

.image-stage {
  position: relative;
  width: min(100vw, calc(100vh * 1672 / 941));
  height: min(100vh, calc(100vw * 941 / 1672));
}

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

.hotspots {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
}

.hotspots rect {
  fill: transparent;
  cursor: pointer;
}

.back-rail {
  position: fixed;
  left: 0;
  top: 50%;
  z-index: 10;
  transform: translateY(-50%);
  width: 56px;
  min-height: 250px;
  display: grid;
  place-items: center;
  color: #ffffff;
  text-decoration: none;
  background: #111;
  border: 1px solid rgba(255,255,255,.65);
  border-left: 0;
  border-radius: 0 14px 14px 0;
}

.back-rail span {
  writing-mode: vertical-rl;
  text-orientation: upright;
  letter-spacing: .18em;
  font-size: 16px;
  font-weight: 700;
}

.back-rail:focus-visible {
  outline: 3px solid #ffffff;
  outline-offset: 3px;
}

@media (max-width: 640px) {
  .back-rail {
    width: 44px;
    min-height: 210px;
  }

  .back-rail span {
    font-size: 14px;
  }
}

.back-rail-small {
  width: 48px;
  min-height: 170px;
  border-radius: 0 12px 12px 0;
}

.back-rail-small span {
  font-size: 14px;
  letter-spacing: .12em;
}

.back-home {
  top: calc(50% - 92px);
}

.back-parent {
  top: calc(50% + 92px);
}

@media (max-width: 640px) {
  .back-rail-small {
    width: 38px;
    min-height: 145px;
  }

  .back-rail-small span {
    font-size: 12px;
    letter-spacing: .08em;
  }

  .back-home {
    top: calc(50% - 78px);
  }

  .back-parent {
    top: calc(50% + 78px);
  }
}