.book-container{display:flex;flex-wrap:wrap;gap:1.5rem}.book-sidebar{flex:0 0 250px;max-width:250px}.book-main{flex:1 1 auto}.book-sidebar .list-group-item.active{background-color:#28a745;border-color:#28a745;color:#fff}.book-sidebar .list-group-item{cursor:pointer;transition:background-color 0.2s ease}.book-sidebar .list-group-item:hover{background-color:#e0f2e9}.book-main h1{font-size:2rem;font-weight:bold;margin-bottom:1rem}.book-main .chapter-content{margin-bottom:2rem}.book-main img{max-width:100%;height:auto;margin:0.5rem 0;border-radius:6px}.book-main p{line-height:1.7}@media (max-width:992px){.book-container{flex-direction:column}.book-sidebar{max-width:100%;flex:1 1 auto;margin-bottom:1.5rem}}.featured-badge{display:inline-block;background-color:#28a745;color:#fff;padding:0.2rem 0.5rem;font-size:0.85rem;border-radius:4px;margin-bottom:0.5rem}