::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: #f8f9fa;
}

::-webkit-scrollbar-thumb {
    background: #e9ecef;
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: #dee2e6;
}

::selection {
    background-color: rgb(0, 0, 0);
    color: black;
}

body {
  margin: 0;
  height: 100vh;
  font-family: "Times New Roman", serif;
  overflow: hidden;
  display: flex;
}

.left-page {
  width: 50%;            
  background: #ff1c1c;
  color: rgb(255, 255, 255);
  position: relative;
}


.left-page {
  box-shadow: inset -25px 0px 40px rgba(0, 0, 0, 0.055);
}

.right-page {
  box-shadow: inset 25px 0px 40px rgba(0, 0, 0, 0.055);
}

.spine {
  width: .03%;
  height: 100vh;
  background: linear-gradient(
      90deg,
      rgba(254, 254, 254, 0.2) 0%,
      rgba(255,255,255,0) 45%,
      rgba(255,255,255,0.25) 100%
  );
}


.right-page {
  width: 50%;           
  background: #fdfdf8;
  color: rgb(0, 0, 0);
  position: relative;
  overflow: hidden;
}


.acknowledgements {
  position: absolute;
  top: 46vh;
  left: 25%;
  width: 95%;
  font-size: 15px;
  line-height: 1.25;
}

.toc-item {
  position: relative;
  width: fit-content;
  margin-bottom: 2px;
}

.toc-main {
  display: inline-block;
}

.subchapter {
  position: absolute;
  left: calc(100% + 12px);
  top: 0;
  white-space: nowrap;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.25s ease;
}

.toc-item:hover .subchapter {
  opacity: 1;
}

.bleed-right {
  position: absolute;
  top: 5vh;
  right: 2%;
  width: 95%;
  font-size: 12px;
  opacity: 0.06;
  transform: scaleX(-1);
  line-height: 1.4;
  color: #000000;
  pointer-events: none;
  column-count: 3;
  font-size: 10px;
  opacity: 0.07;
}


.bleed-left {
  position: absolute;
  top: 5vh;
  left: 2%;
  width: 95%;
  transform: scaleX(-1);
  line-height: 1.4;
  color: #8ACE00;
  pointer-events: none;
  font-size: 15px;
  opacity: 0.20;
}

.arrow {
  position: absolute;
  bottom: 4vh;
  right: 3vw;
  font-size: 40px;
  color: #0033ff;
  text-decoration: none;
}

.arrow-left{
  position: absolute;
  bottom: 4vh;
  left: 3vw;
  font-size: 40px;
  color: #ffffff;
  text-decoration: none;
}

.contents {
  position: absolute;
  top: 20%;
  left: 8%;
  width: 90%;
  height: 82vh;
  font-size: 15px;
  line-height: 1.25;
}

.contents3 {
  position: absolute;
  top: 20%;
  right: 10%;
  width: 90%;
  height: 82vh;
  font-size: 15px;
  line-height: 1.25;

}

.contents2 {
  position: absolute;
  top: 30%;
  left: 30%;
  width: 40%;
  height: 82vh;
  font-size: 15px;
  line-height: 1.25;
}

img {
  max-width: 90%;
}

.introduction {
   position: absolute;
  top: 30%;
  left: 30%;
  width: 40%;
  height: 82vh;
  font-size: 15px;
  line-height: 1.25;
}

.introduction3 {
margin-top: 20%;
  margin-left: 10%;  
  text-align: center;
  justify-content: center;
  width: 100%;
  font-size:3em;
}

.title {
  font-size: 1.2em;
  margin-top: 35%;
  text-align: center;
  justify-content: center;
}

.title2 {
font-family: 'Times New Roman', Times, serif;
  font-size: 3em;
  margin-top: 15%;
  text-align: center;
  justify-content: center;
}

.documentation {
   position: absolute;
  top: -3%;
  left: 30%;
  width: 40%;
  height: 82vh;
  font-size: 15px;
  line-height: 1.25;
}

#mobile-block {
  display: none;
  position: fixed;
  inset: 0;
  background: #0033ff;
  color: #ffffff;
  font-family: "Times New Roman", serif;
  font-size: 20px;
  padding: 40px;
  line-height: 1.4;
  z-index: 999999;
}

@media (max-width: 900px) {
  #mobile-block {
    display: flex;
    align-items: center;
    justify-content:center;
    text-align: center; 
    }

  body > *:not(#mobile-block) { 
    display: none !important; 
    }
}