.section1 {
    display: flex;
    justify-content: center;
    align-items: center;
    transform-style: preserve-3d;
    perspective: 1000px;
    margin-top: 50px;
    margin-left: 15px;
}

.section1 .book {
    position: relative;
    width: 383px;
    height: 567px;
    box-shadow: 20px 20px 20px rgba(0, 0, 0, 0.2);
    transform-style: preserve-3d;
    transition: 0.5s;
}

.section1 .book:hover {
    transform: rotateY(35deg);
    box-shadow: 0px 20px 20px rgba(0, 0, 0, 0.2);
}

.section1 .book:active {
    transform: rotateY(180deg);
}

.section1 .book::before {
    content: '';
    position: absolute;
    width: 60px;
    height: 100%;
    transform-origin: left;
    margin-left: -192px;
    margin-top: 0px;
    background: url(../images/Lề\ sách.png);
    background-position: center;
    transform: rotateY(90deg);
}

.section1 .book::after {
    content: '';
    position: absolute;
    width: 100%;
    height: 100%;
    margin-left: -192px;
    transform-origin: center;
    background: url(../images/Bìa\ cuối.png);
    background-position: center;
    transform: rotateY(180deg) translateZ(60px);
}

.section1 .book img {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
}