* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  background-repeat: no-repeat;
  background-attachment: fixed;
  background-image: radial-gradient(circle at center, rgb(0, 55, 97, .64), rgb(0, 55, 97));
}

:root {
  --bu: rgb(0, 55, 97);
  --w: #FFFFFF;
  --art: #679873;
}

img {
  width: 20em;
  height: 30em;
}

.title {
  position: absolute;
  top: 2vh;
  left: 2vw;
  font-size: 1.6em;
  color: white;
  font-family: "overpass", sans-serif;
}

.bub {
  position: absolute;
  bottom: 2%;
  left: 2%;
  border-radius: 50%;
  width: 72px;
  height: 72px;
  background-color: var(--w);
  font-family: "overpass", sans-serif;
}

.bub a {
  position: absolute;
  top: 32%;
  left: 20%;
  text-decoration: none;
  color: var(--bu);
  font-size: 1.2em;
}

.bub a:hover {
  color: var(--art);
}

/* Book */
.book {
    position: relative;
    width: 350px;
    height: 500px;
    transition: transform 0.5s;
}

.paper {
    position: absolute;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    perspective: 1500px;
}

.front, .back {
    background-color: white;
    position: absolute;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    transform-origin: left;
    transition: transform 0.5s;
}

.front {
    z-index: 1;
    backface-visibility: hidden;
    border-left: 6px solid var(--bu);
}

.back {
    z-index: 0;
}

.front-content, .back-content {
    width: 100%;
    height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
}

.back-content {
    transform: rotateY(180deg)
}

/* Paper flip effect */
.flipped .front, .flipped .back {
    transform: rotateY(-180deg);
}

/* Controller Buttons */
button {
    border: none;
    background-color: transparent;
    cursor: pointer;
    margin: 10px;
    transition: transform 0.5s;
}

button:focus {
    outline: none;
}

button:hover i {
    color: var(--w);
}

i {
    font-size: 50px;
    color: var(--bu);
}

.not-available {
  display: none;
}

/* Paper stack order */
#p1 {
    z-index: 11;
}

#p2 {
    z-index: 10;
}

#p3 {
    z-index: 9;
}

#p4 {
    z-index: 8;
}

#p5 {
    z-index: 7;
}

#p6 {
    z-index: 6;
}

#p7 {
    z-index: 5;
}

#p8 {
    z-index: 4;
}

#p9 {
    z-index: 3;
}

#p10 {
    z-index: 2;
}

#p11 {
    z-index: 1;
}


@media (max-width: 840px) {
  .book {
    display: none;
  }
  button {
    display: none;
  }
  .not-available {
    display: block;
    text-align: center;
    color: white;
    font-size: 1.6em;
    font-family: "catamaran", sans-serif;
  }
}