/* Folha em 3D: frente e verso giram ao redor da lombada. */
.turn-sheet {
    position: absolute;
    top: 0;
    width: 50%;
    z-index: 5;
    transform-style: preserve-3d;
    pointer-events: none;
    will-change: transform;
}

.turn-forward {
    left: 50%;
    transform-origin: left center;
}

.turn-backward {
    left: 0;
    transform-origin: right center;
}

.turn-face {
    position: absolute;
    inset: 0;
    backface-visibility: hidden;
    -webkit-backface-visibility: hidden;
    overflow: hidden;
    box-shadow: 0 4px 25px #0005;
}

.turn-front {
    transform: translateZ(0.5px);
}

.turn-reverse {
    transform: rotateY(180deg) translateZ(0.5px);
}

.turn-face .page,
.turn-stationary .page {
    min-height: 100%;
    height: 100%;
    width: 100%;
}

.turn-stationary {
    position: absolute;
    top: 0;
    bottom: 0;
    width: 50%;
    z-index: 3;
    overflow: hidden;
    pointer-events: none;
}

.turn-stationary.is-left {
    left: 0;
}

.turn-stationary.is-right {
    right: 0;
}

.turn-sheet.turn-single {
    width: 100%;
    left: 0;
    transform-origin: center center;
}

/* A coleção acompanha a abertura do volume escolhido. */
.book-collection.is-opening {
    pointer-events: none;
}

.book-collection.is-opening .collection-book {
    transform: none;
    transition: none;
}

.book-collection.is-opening .collection-book:not(.is-selected) {
    animation: collection-book-away 420ms ease forwards;
}

.book-collection.is-opening .collection-book.is-selected {
    position: relative;
    z-index: 2;
}

@keyframes collection-book-away {
    from {
        opacity: 1;
        transform: translateY(0);
    }

    to {
        opacity: 0;
        transform: translateY(12px);
    }
}