html,
body {
  margin: 0;
  padding: 0;
  width: 100%;
  height: 100%;
  overflow: hidden;
  background-color: #0d0905;
}

.app-container {
  position: relative;
  width: 100%;
  height: 100%;
  display: flex;
  justify-content: center;
  align-items: center;
  background-image: url('../assets/images/bg/table.webp');
  background-size: 125%;
  background-position: 50% center;
  background-repeat: no-repeat;
  container-type: size;
  transition: background-position var(--timing-page-turn) var(--easing-page-turn),
    background-size var(--timing-page-turn) var(--easing-page-turn);
}

.app-container.state-cover-front {
  background-position: 42% center;
  background-size: 135%;
}

.app-container.state-opened {
  background-position: 50% center;
  background-size: 125%;
}

.app-container.state-cover-back {
  background-position: 58% center;
  background-size: 135%;
}

.book-viewport {
  width: 100%;
  height: 100%;
  display: flex;
  justify-content: center;
  align-items: center;
  perspective: 300cqw;
  perspective-origin: 50% 50%;
  transition: opacity 1.5s ease;
}

.viewport-logo {
  position: absolute;
  top: 2cqh;
  left: 2cqw;
  width: 10cqw;
  height: auto;
  z-index: 100;
  pointer-events: none;
  filter: drop-shadow(0 0.2cqw 0.4cqw rgba(0, 0, 0, 0.4));
}