@charset "UTF-8";
.book-items{
    display:grid;
    grid-template-columns:repeat(4,1fr);
    gap:2.25rem;
}
.book-items .btn-book-item{
    display:flex;
    flex-direction:column;
}
.book-items .btn-book-item .book-thumb{
    background-color:#ffffff;
    position:relative;
    z-index:1;
    cursor:pointer;
}
.book-items .btn-book-item .book-thumb:before{
    content:'';
    background-color:#f4f4f4;
    border:1px solid #ccc;
    position:absolute;
    z-index:-1;
    top:0;
    left:0;
    display:block;
    width:100%;
    height:100%;
    transform:rotateZ(0);
    transition:all 0.3s;
}
.book-items .btn-book-item .book-thumb:after{
    content:'';
    background-color:#f4f4f4;
    position:absolute;
    z-index:-1;
    top:0;
    left:0;
    display:block;
    width:100%;
    height:100%;
    transform:rotateZ(0);
    transition:all 0.3s;
}
.book-items .btn-book-item .book-thumb > img{
    width:100%;
    box-shadow:0px 0px 2px rgba(0,0,0,0.5);        
}
.book-items .btn-book-item:hover .book-thumb > img{
    box-shadow:0px 0px 2px rgba(0,0,0,0.5);
}
.book-items .btn-book-item:hover .book-thumb:after,.book-items .btn-book-item:active .book-thumb:after{
    transform:rotateZ(-7deg);
    transition:all 0.3s;
    box-shadow:0px 0px 2px rgba(0,0,0,0.35);
}
.book-items .btn-book-item:hover .book-thumb:before,.book-items .btn-book-item:active .book-thumb:before{
    transform:rotateZ(-3deg);
    transition:all 0.3s;
    box-shadow:0px 0px 2px rgba(0,0,0,0.35);
}
.book-title{
    margin-top:15px;
    padding:5px;
    text-align:center;
    color:#f8f8f8;
    background-color:#2a2a2a;
}
.pdf-down-btn{
    display:flex;
    align-items:center;
    justify-content:center;
    gap:10px;
    color:#333333;
    font-size:0.85rem;
    background-color:#eeeeee;
}
.pdf-down-btn:hover,.pdf-down-btn:active{
    color:#1748a4;
    font-weight:600;
}

@media (max-width:1024px){
    .book-items{
        display:grid;
        grid-template-columns:repeat(2,1fr);
        gap:2.25rem;
    }
}

@media (max-width:460px){
    .book-items{
        display:grid;
        grid-template-columns:repeat(1,1fr);
        gap:2.25rem;
    }
}