.book-viewer {
    position: fixed;
    inset: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    opacity: 0;
    visibility: hidden;
    transition:
        opacity .30s ease,
        visibility .30s ease;
    z-index: 9999;
}
.book-viewer.active {
    opacity: 1;
    visibility: visible;
}
.book-viewer-overlay {
    position: absolute;
    inset: 0;
    background: rgba(18, 18, 18, .82);
    backdrop-filter: blur(4px);
}
.book-viewer-content {
    position: relative;
    width: min(90vw, 900px);
    display: flex;
    flex-direction: column;
    align-items: center;
    z-index: 2;
}
.book-viewer-title {
    margin-bottom: 30px;
    color: white;
    font-family: var(--font-display);
    font-size: 1.6rem;
    text-align: center;
}
.book-viewer-stage {
    width: 100%;
    display: grid;
    grid-template-columns: 70px 1fr 70px;
    align-items: center;
}
.book-viewer-image {
    width: 100%;
    max-height: 75vh;
    object-fit: contain;
    border-radius: 10px;
    box-shadow:
        0 25px 70px rgba(0, 0, 0, .35);
    background: white;
}
.book-viewer-prev,
.book-viewer-next {
    background: none;
    border: none;
    cursor: pointer;
    color: rgba(255, 255, 255, .55);
    font-size: 2rem;
    transition: .25s;
}
.book-viewer-prev:hover,
.book-viewer-next:hover {
    color: white;
}
.book-viewer-close {
    position: absolute;
    top: -10px;
    right: 0;
    background: none;
    border: none;
    color: white;
    font-size: 1.6rem;
    cursor: pointer;
}
.book-viewer-counter {
    margin-top: 25px;
    color: rgba(255, 255, 255, .75);
    font-size: .95rem;
}