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

body {
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    font-family: sans-serif;
    background-image: url("../imagesarchive/background-book.jpg");
    background-repeat: no-repeat;
    background-size: cover;
}

/* Book */
.book-container {
    display: flex;
    justify-content: center;
    align-items: center;
}

.book {
    position: relative;
    width: 25vw;
    height: calc(25vw * 1.4);
    transition: transform 0.5s;
    border-radius: 10px;
}

.paper {
    position: absolute;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    perspective: 1500px;
    border-radius: 10px;
}

.front,
.back {
    position: absolute;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: white;
    transform-origin: left;
    transition: transform 0.5s;
    border-radius: 10px;
}

.front {
    z-index: 1;
    backface-visibility: hidden;
    border-left: 3px solid #9D8465;
}

.back {
    z-index: 0;
}

.front-content,
.back-content {
    width: 100%;
    height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    border-radius: 10px;
}

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

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

/* Controller Buttons */
button {
    border: none;
    height: 20vh;
    background-color: transparent;
    cursor: pointer;
    margin: 0 20vw;
    padding: 0;
}

button:focus {
    outline: none;
}

button:hover i {
    color: #636363;
}

i {
    font-size: 50px;
    color: gray;
}

.mobile-overlay {
  display: none;
}

.cover-img {
    width: 100%;
    height: 100%;
    object-fit: fill;
    border-radius: 10px;
}

.terug-wrapper {
  position: absolute;
  height: 58px;
  width: 84px;
  left: 35px;
  top: 35px;
  z-index: 6;
  background: white;
  border-radius: 10px;
  border: dashed #dca 1px;
}

.terug, .terug-hover {
    position: absolute;
    left: 10%;
    top: -35%;
    height: 100px;
    width: 150px;
}

.terug img, .terug-hover img {
    height: 100px;
    width: auto;
}

.terug-hover img {
    display: none;
}

.terug-wrapper:hover {
    border: dashed black 1px;

}

.terug-wrapper:hover .terug-hover img,
.terug-wrapper:focus-within .terug-hover img {
    display: block;
}

.terug-wrapper:hover .terug img,
.terug-wrapper:focus-within .terug img {
    display: none;
}

@media (max-width: 768px) {

  button {
    padding: 10px;
    margin: 5px;
  }

  i, button img {
    width: 30px;
    height: 30px;
  }

  .mobile-overlay {
    display: flex;
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background-color: rgba(255, 255, 255, 1);
    z-index: 9999;
    justify-content: center;
    align-items: center;
    text-align: center;
    padding: 20px;
    font-size: 1.5rem;
    font-weight: bold;
    color: #333;
    z-index: 89;
  } 
}