body {
  font-family: Arial, sans-serif;
  margin: 0;
  padding: 0;
  overflow: hidden; /* This will be removed after preloader */
}

.preloader {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: #1a202c;
  display: flex;
  justify-content: center;
  align-items: center;
  z-index: 9999;
}

.book {
  --color: #fff;
  --duration: 2s;
  width: 50px;
  height: 50px;
  position: relative;
  zoom: 1.5;
  transform-style: preserve-3d;
  transform-origin: center;
}

.book .inner {
  width: 50px;
  height: 50px;
  position: relative;
  transform-origin: center;
  transform: rotateY(deg);
  animation: book var(--duration) ease infinite;
}

.book .inner .left,
.book .inner .right {
  width: 50px;
  height: 50px;
  top: 0;
  background: var(--color);
  position: absolute;
  backface-visibility: hidden;
}

.book .inner .left {
  left: 0;
  transform-origin: left;
}

.book .inner .right {
  left: 0;
  transform: rotateY(180deg);
  transform-origin: right;
}

.book .inner .middle {
  width: 50px;
  height: 50px;
  border: 4px solid var(--color);
  border-top: 0;
  border-radius: 0 0 9px 9px;
  transform: translateY(2px);
}

@keyframes book {
  0% { transform: rotateY(0deg); }
  50% { transform: rotateY(180deg); }
  100% { transform: rotateY(360deg); }
}

.main-content {
  display: none;
  padding: 0;
}