:root{--primary-color: #2563eb;--primary-hover: #1d4ed8;--secondary-color: #64748b;--success-color: #10b981;--warning-color: #f59e0b;--danger-color: #ef4444;--background-light: #f8fafc;--background-dark: #0f172a;--card-light: #ffffff;--card-dark: #1e293b;--text-light: #1e293b;--text-dark: #f1f5f9;--border-light: #e2e8f0;--border-dark: #334155;--shadow: 0 4px 6px -1px rgba(0, 0, 0, .1);--shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, .1);--border-radius: 8px;--transition: all .2s ease-in-out}*{margin:0;padding:0;box-sizing:border-box}body{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,sans-serif;line-height:1.6;transition:var(--transition)}body.dark-mode{background-color:var(--background-dark);color:var(--text-dark)}.app{min-height:100vh;background-color:var(--background-light);color:var(--text-light);transition:var(--transition)}.app.dark{background-color:var(--background-dark);color:var(--text-dark)}.header{background:var(--card-light);border-bottom:1px solid var(--border-light);padding:1.5rem 2rem;box-shadow:var(--shadow);position:sticky;top:0;z-index:100}.dark .header{background:var(--card-dark);border-color:var(--border-dark)}.header-content{max-width:1200px;margin:0 auto;display:flex;justify-content:space-between;align-items:center;margin-bottom:1rem}.header h1{font-size:2rem;font-weight:700;color:var(--primary-color)}.header-actions{display:flex;gap:1rem;align-items:center}.btn-add{background:var(--primary-color);color:#fff;border:none;padding:.75rem 1.5rem;border-radius:var(--border-radius);font-weight:600;cursor:pointer;transition:var(--transition)}.btn-add:hover{background:var(--primary-hover);transform:translateY(-1px)}.dark-toggle{background:var(--secondary-color);color:#fff;border:none;padding:.5rem;border-radius:50%;width:40px;height:40px;cursor:pointer;transition:var(--transition);display:flex;align-items:center;justify-content:center}.dark-toggle:hover{transform:scale(1.1)}.stats-bar{max-width:1200px;margin:0 auto;display:grid;grid-template-columns:repeat(auto-fit,minmax(120px,1fr));gap:1rem}.stat{text-align:center;padding:1rem;background:#2563eb1a;border-radius:var(--border-radius);border:1px solid rgba(37,99,235,.2)}.stat-number{display:block;font-size:1.5rem;font-weight:700;color:var(--primary-color)}.stat-label{font-size:.875rem;color:var(--secondary-color);text-transform:uppercase;letter-spacing:.05em}main{max-width:1200px;margin:0 auto;padding:2rem}.controls{display:flex;gap:1rem;margin-bottom:2rem;flex-wrap:wrap}.search-container{flex:1;min-width:300px}.search-input{width:100%;padding:.75rem 1rem;border:2px solid var(--border-light);border-radius:var(--border-radius);font-size:1rem;transition:var(--transition);background:var(--card-light);color:var(--text-light)}.dark .search-input{background:var(--card-dark);color:var(--text-dark);border-color:var(--border-dark)}.search-input:focus{outline:none;border-color:var(--primary-color);box-shadow:0 0 0 3px #2563eb1a}.filters{display:flex;gap:.5rem}.filter-select,.sort-select{padding:.75rem;border:2px solid var(--border-light);border-radius:var(--border-radius);background:var(--card-light);color:var(--text-light);cursor:pointer;transition:var(--transition)}.dark .filter-select,.dark .sort-select{background:var(--card-dark);color:var(--text-dark);border-color:var(--border-dark)}.loading{text-align:center;padding:3rem}.spinner{width:40px;height:40px;border:4px solid var(--border-light);border-top:4px solid var(--primary-color);border-radius:50%;animation:spin 1s linear infinite;margin:0 auto 1rem}@keyframes spin{0%{transform:rotate(0)}to{transform:rotate(360deg)}}.error-message{background:#fef2f2;border:1px solid #fecaca;color:#dc2626;padding:1rem;border-radius:var(--border-radius);margin-bottom:1rem;display:flex;justify-content:space-between;align-items:center}.dark .error-message{background:#ef44441a;border-color:#ef44444d}.book-list{margin-top:2rem}.book-count{margin-bottom:1rem;color:var(--secondary-color);font-weight:500}.books-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(400px,1fr));gap:1.5rem}.empty-state{text-align:center;padding:4rem 2rem;color:var(--secondary-color)}.empty-icon{font-size:4rem;margin-bottom:1rem}.empty-state h3{font-size:1.5rem;margin-bottom:.5rem;color:var(--text-light)}.dark .empty-state h3{color:var(--text-dark)}.book-card{background:var(--card-light);border:1px solid var(--border-light);border-radius:var(--border-radius);padding:1.5rem;box-shadow:var(--shadow);transition:var(--transition)}.dark .book-card{background:var(--card-dark);border-color:var(--border-dark)}.book-card:hover{transform:translateY(-2px);box-shadow:var(--shadow-lg)}.book-card-header{display:flex;justify-content:space-between;align-items:flex-start;margin-bottom:1rem}.book-title{font-size:1.25rem;font-weight:700;margin-bottom:.25rem;color:var(--text-light)}.dark .book-title{color:var(--text-dark)}.book-author{color:var(--secondary-color);font-style:italic;margin-bottom:.5rem}.book-meta{display:flex;gap:1rem;font-size:.875rem}.book-category{background:var(--primary-color);color:#fff;padding:.25rem .5rem;border-radius:4px;font-size:.75rem;font-weight:500}.book-year{color:var(--secondary-color)}.status-select{padding:.5rem;border:1px solid var(--border-light);border-radius:4px;background:var(--card-light);font-size:.875rem;cursor:pointer}.dark .status-select{background:var(--card-dark);border-color:var(--border-dark);color:var(--text-dark)}.book-description{margin-bottom:1rem;line-height:1.6;color:var(--secondary-color)}.toggle-details{background:none;border:none;color:var(--primary-color);cursor:pointer;font-size:.875rem;margin-left:.5rem}.book-rating{display:flex;align-items:center;gap:.5rem;margin-bottom:1rem}.stars{display:flex;gap:.25rem}.star{cursor:pointer;font-size:1.2rem;opacity:.3;transition:var(--transition)}.star.filled{opacity:1}.star:hover{opacity:.8;transform:scale(1.1)}.rating-value{font-size:.875rem;color:var(--secondary-color)}.book-stats{display:flex;justify-content:space-between;align-items:center;margin-bottom:1rem;font-size:.875rem}.like-btn{background:var(--success-color);color:#fff;border:none;padding:.5rem .75rem;border-radius:4px;cursor:pointer;transition:var(--transition);font-size:.875rem}.like-btn:hover{transform:scale(1.05)}.date-added{color:var(--secondary-color)}.book-isbn{margin-bottom:1rem}.book-isbn small{color:var(--secondary-color);font-family:monospace}.book-actions{display:flex;gap:.5rem;justify-content:flex-end}.btn-edit,.btn-delete{padding:.5rem .75rem;border:none;border-radius:4px;cursor:pointer;font-size:.875rem;transition:var(--transition)}.btn-edit{background:var(--warning-color);color:#fff}.btn-delete{background:var(--danger-color);color:#fff}.btn-edit:hover,.btn-delete:hover{transform:translateY(-1px);opacity:.9}.book-form-container{background:var(--card-light);border:1px solid var(--border-light);border-radius:var(--border-radius);padding:2rem;margin-bottom:2rem;box-shadow:var(--shadow)}.dark .book-form-container{background:var(--card-dark);border-color:var(--border-dark)}.book-form-container h2{margin-bottom:1.5rem;color:var(--primary-color)}.book-form{display:flex;flex-direction:column;gap:1.5rem}.form-row{display:grid;grid-template-columns:repeat(auto-fit,minmax(250px,1fr));gap:1rem}.form-group{display:flex;flex-direction:column}.form-group label{margin-bottom:.5rem;font-weight:600;color:var(--text-light)}.dark .form-group label{color:var(--text-dark)}.form-group input,.form-group select,.form-group textarea{padding:.75rem;border:2px solid var(--border-light);border-radius:var(--border-radius);font-size:1rem;transition:var(--transition);background:var(--card-light);color:var(--text-light)}.dark .form-group input,.dark .form-group select,.dark .form-group textarea{background:var(--card-dark);color:var(--text-dark);border-color:var(--border-dark)}.form-group input:focus,.form-group select:focus,.form-group textarea:focus{outline:none;border-color:var(--primary-color);box-shadow:0 0 0 3px #2563eb1a}.form-group input.error,.form-group select.error,.form-group textarea.error{border-color:var(--danger-color)}.error-message{color:var(--danger-color);font-size:.875rem;margin-top:.25rem}.form-actions{display:flex;gap:1rem;justify-content:flex-end;margin-top:1rem}.btn-primary{background:var(--primary-color);color:#fff;border:none;padding:.75rem 1.5rem;border-radius:var(--border-radius);font-weight:600;cursor:pointer;transition:var(--transition)}.btn-primary:hover{background:var(--primary-hover);transform:translateY(-1px)}.btn-secondary{background:var(--secondary-color);color:#fff;border:none;padding:.75rem 1.5rem;border-radius:var(--border-radius);font-weight:600;cursor:pointer;transition:var(--transition)}.btn-secondary:hover{opacity:.9;transform:translateY(-1px)}@media(max-width:768px){.header-content{flex-direction:column;gap:1rem;text-align:center}.controls{flex-direction:column}.filters{justify-content:center}.books-grid,.form-row{grid-template-columns:1fr}.book-card-header{flex-direction:column;gap:1rem}.book-actions{justify-content:center}main{padding:1rem}}.stats-container{background:var(--card-light);border:1px solid var(--border-light);border-radius:var(--border-radius);padding:2rem;margin-bottom:2rem;box-shadow:var(--shadow)}.dark .stats-container{background:var(--card-dark);border-color:var(--border-dark)}.stats-container h2{margin-bottom:1.5rem;color:var(--primary-color);text-align:center}.stats-loading{text-align:center;padding:2rem;color:var(--secondary-color)}.stats-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(200px,1fr));gap:1rem;margin-bottom:2rem}.stat-card{background:linear-gradient(135deg,var(--primary-color),var(--primary-hover));color:#fff;padding:1.5rem;border-radius:var(--border-radius);display:flex;align-items:center;gap:1rem;box-shadow:var(--shadow);transition:var(--transition)}.stat-card:hover{transform:translateY(-2px);box-shadow:var(--shadow-lg)}.stat-icon{font-size:2rem;opacity:.9}.stat-content{flex:1}.stat-card .stat-number{font-size:2rem;font-weight:700;line-height:1;margin-bottom:.25rem}.stat-card .stat-label{font-size:.875rem;opacity:.9;text-transform:uppercase;letter-spacing:.05em}.recent-books{margin-bottom:2rem}.recent-books h3{margin-bottom:1rem;color:var(--text-light)}.dark .recent-books h3{color:var(--text-dark)}.recent-list{display:flex;flex-direction:column;gap:.75rem}.recent-item{display:flex;justify-content:space-between;align-items:center;padding:1rem;background:#2563eb0d;border:1px solid rgba(37,99,235,.1);border-radius:var(--border-radius);transition:var(--transition)}.recent-item:hover{background:#2563eb1a}.recent-info{display:flex;flex-direction:column;gap:.25rem}.recent-info strong{color:var(--text-light)}.dark .recent-info strong{color:var(--text-dark)}.recent-info span{color:var(--secondary-color);font-size:.875rem}.recent-date{color:var(--secondary-color);font-size:.875rem;font-weight:500}.data-management h3{margin-bottom:1rem;color:var(--text-light)}.dark .data-management h3{color:var(--text-dark)}.data-actions{display:flex;gap:1rem;margin-bottom:1rem;flex-wrap:wrap}.btn-export,.btn-import{background:var(--success-color);color:#fff;border:none;padding:.75rem 1.5rem;border-radius:var(--border-radius);font-weight:600;cursor:pointer;transition:var(--transition);text-decoration:none;display:inline-block}.btn-export:hover,.btn-import:hover{opacity:.9;transform:translateY(-1px)}.data-info{color:var(--secondary-color);font-size:.875rem;line-height:1.5}.tabs-container{margin-bottom:2rem}.tabs-nav{display:flex;border-bottom:2px solid var(--border-light);margin-bottom:2rem}.dark .tabs-nav{border-color:var(--border-dark)}.tab-button{background:none;border:none;padding:1rem 1.5rem;cursor:pointer;font-weight:600;color:var(--secondary-color);border-bottom:2px solid transparent;transition:var(--transition)}.tab-button:hover{color:var(--primary-color)}.tab-button.active{color:var(--primary-color);border-bottom-color:var(--primary-color)}.tab-content{min-height:400px}@media(max-width:768px){.stats-grid{grid-template-columns:repeat(auto-fit,minmax(150px,1fr))}.stat-card{padding:1rem;flex-direction:column;text-align:center}.stat-icon,.stat-card .stat-number{font-size:1.5rem}.recent-item{flex-direction:column;align-items:flex-start;gap:.5rem}.data-actions{flex-direction:column}.btn-export,.btn-import{text-align:center}}