:root{--color-primary: #2563eb;--color-primary-dark: #1d4ed8;--color-success: #16a34a;--color-danger: #dc2626;--color-warning: #d97706;--color-bg: #f8fafc;--color-surface: #ffffff;--color-text: #0f172a;--color-text-secondary: #64748b;--color-border: #e2e8f0;--radius: 12px;--radius-sm: 8px;--shadow: 0 1px 3px rgba(0,0,0,.08), 0 1px 2px rgba(0,0,0,.06);--shadow-lg: 0 4px 12px rgba(0,0,0,.1);--font: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif}*,*:before,*:after{box-sizing:border-box;margin:0;padding:0}html,body{font-family:var(--font);font-size:16px;line-height:1.5;color:var(--color-text);background:var(--color-bg);-webkit-font-smoothing:antialiased;-webkit-tap-highlight-color:transparent;overflow-x:hidden}body{min-height:100dvh;padding-bottom:env(safe-area-inset-bottom,0)}#app{max-width:480px;margin:0 auto;padding:0 16px;min-height:100dvh;display:flex;flex-direction:column}.header{display:flex;align-items:center;justify-content:space-between;padding:16px 0;border-bottom:1px solid var(--color-border);margin-bottom:20px}.header h1{font-size:1.25rem;font-weight:700}.header-badge{font-size:.75rem;color:var(--color-text-secondary);background:var(--color-border);padding:2px 10px;border-radius:999px}.btn{display:flex;align-items:center;justify-content:center;gap:10px;width:100%;padding:16px 20px;border:none;border-radius:var(--radius);font-size:1.05rem;font-weight:600;font-family:var(--font);cursor:pointer;transition:transform .1s,opacity .15s;-webkit-user-select:none;user-select:none}.btn:active{transform:scale(.97)}.btn:disabled{opacity:.5;cursor:not-allowed;transform:none}.btn-primary{background:var(--color-primary);color:#fff}.btn-primary:hover:not(:disabled){background:var(--color-primary-dark)}.btn-success{background:var(--color-success);color:#fff}.btn-danger{background:var(--color-danger);color:#fff}.btn-outline{background:var(--color-surface);color:var(--color-text);border:2px solid var(--color-border)}.btn-outline:hover:not(:disabled){border-color:var(--color-primary);color:var(--color-primary)}.btn-sm{padding:10px 16px;font-size:.9rem}.btn-icon{font-size:1.4rem;line-height:1}.card{background:var(--color-surface);border-radius:var(--radius);box-shadow:var(--shadow);padding:20px;margin-bottom:12px}.menu-grid{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin-bottom:20px}.menu-btn{display:flex;flex-direction:column;align-items:center;gap:8px;padding:24px 12px;background:var(--color-surface);border:2px solid var(--color-border);border-radius:var(--radius);font-size:.95rem;font-weight:600;font-family:var(--font);color:var(--color-text);cursor:pointer;transition:border-color .15s,transform .1s}.menu-btn:active{transform:scale(.97)}.menu-btn:hover{border-color:var(--color-primary)}.menu-btn .icon{font-size:2rem}.menu-btn--checkout{border-color:var(--color-primary);color:var(--color-primary)}.menu-btn--return{border-color:var(--color-success);color:var(--color-success)}.menu-btn--status{border-color:var(--color-warning)}.menu-btn--overdue{border-color:var(--color-danger)}.input{width:100%;padding:14px 16px;border:2px solid var(--color-border);border-radius:var(--radius-sm);font-size:1rem;font-family:var(--font);background:var(--color-surface);transition:border-color .15s}.input:focus{outline:none;border-color:var(--color-primary)}.input-group{margin-bottom:16px}.input-group label{display:block;font-size:.85rem;font-weight:600;color:var(--color-text-secondary);margin-bottom:6px}.student-list{list-style:none;max-height:50vh;overflow-y:auto;-webkit-overflow-scrolling:touch}.student-item{display:flex;align-items:center;justify-content:space-between;padding:14px 16px;border-bottom:1px solid var(--color-border);cursor:pointer;transition:background .1s}.student-item:active,.student-item:hover{background:#f1f5f9}.student-item .name{font-weight:500}.student-item .class-badge{font-size:.8rem;color:var(--color-text-secondary);background:var(--color-border);padding:2px 8px;border-radius:999px}.result-card{text-align:center;padding:32px 20px}.result-icon{font-size:3rem;margin-bottom:12px}.result-card h2{font-size:1.2rem;margin-bottom:8px}.result-card p{color:var(--color-text-secondary);margin-bottom:4px}.result-success{color:var(--color-success)}.result-error{color:var(--color-danger)}.scanner-container{position:relative;width:100%;aspect-ratio:4/3;background:#000;border-radius:var(--radius);overflow:hidden;margin-bottom:16px}.scanner-container video{width:100%;height:100%;object-fit:cover}.scanner-overlay{position:absolute;top:0;right:0;bottom:0;left:0;display:flex;align-items:center;justify-content:center}.scanner-crosshair{width:70%;max-width:280px;aspect-ratio:3/1;border:3px solid rgba(255,255,255,.7);border-radius:8px}.text-center{text-align:center}.text-secondary{color:var(--color-text-secondary)}.text-sm{font-size:.85rem}.mt-12{margin-top:12px}.mt-20{margin-top:20px}.mb-12{margin-bottom:12px}.mb-20{margin-bottom:20px}.gap-12{gap:12px}.flex-col{display:flex;flex-direction:column}.onboarding{display:flex;flex-direction:column;align-items:center;justify-content:center;min-height:80dvh;text-align:center;padding:20px}.onboarding h1{font-size:1.5rem;margin-bottom:12px}.onboarding p{color:var(--color-text-secondary);max-width:300px;margin-bottom:24px}.back-btn{display:inline-flex;align-items:center;gap:4px;padding:8px 0;margin-bottom:12px;background:none;border:none;font-size:.95rem;font-weight:500;color:var(--color-primary);cursor:pointer;font-family:var(--font)}.overdue-item{display:flex;justify-content:space-between;align-items:flex-start;padding:12px 0;border-bottom:1px solid var(--color-border)}.overdue-item:last-child{border-bottom:none}.overdue-isbn{font-family:monospace;font-size:.8rem;color:var(--color-text-secondary)}.overdue-days{font-weight:600;color:var(--color-danger);white-space:nowrap;font-size:.85rem}.spinner{display:inline-block;width:24px;height:24px;border:3px solid var(--color-border);border-top-color:var(--color-primary);border-radius:50%;animation:spin .6s linear infinite}@keyframes spin{to{transform:rotate(360deg)}}.loading-screen{display:flex;flex-direction:column;align-items:center;justify-content:center;gap:16px;min-height:40vh;color:var(--color-text-secondary)}.app-main{flex:1}.app-footer{margin-top:auto;padding:16px 0 12px;border-top:1px solid var(--color-border);color:#94a3b8;text-align:center}.app-footer-links{display:inline-flex;align-items:center;gap:8px;margin-bottom:6px}.footer-link{background:none;border:none;color:#94a3b8;font-size:.82rem;font-family:var(--font);cursor:pointer;padding:0}.footer-link:hover{color:#64748b;text-decoration:underline}.footer-separator{color:#cbd5e1;font-size:.8rem}.app-footer-note{font-size:.72rem;line-height:1.3}.legal-content h3{font-size:1.05rem;margin:10px 0 8px}.legal-content h4{font-size:.95rem;margin:10px 0 6px;color:var(--color-text-secondary)}.legal-content p{margin-bottom:10px;color:var(--color-text)}.legal-content ul{margin:0 0 10px 18px}.legal-content li{margin-bottom:4px}.stats-strip{display:flex;align-items:center;justify-content:space-around;background:var(--color-surface);border-radius:var(--radius-sm);box-shadow:var(--shadow);padding:12px 16px;margin-top:16px;margin-bottom:16px}.stats-strip--loading{gap:12px}.stat-item{display:flex;flex-direction:column;align-items:center;gap:2px}.stat-value{font-size:1.4rem;font-weight:700;line-height:1;color:var(--color-text)}.stat-value--overdue{color:var(--color-danger)}.stat-label{font-size:.72rem;font-weight:500;color:var(--color-text-secondary);text-transform:uppercase;letter-spacing:.04em}.stats-divider{width:1px;height:32px;background:var(--color-border)}.stats-skeleton{flex:1;height:36px;background:var(--color-border);border-radius:var(--radius-sm);animation:pulse 1.2s ease-in-out infinite}@keyframes pulse{0%,to{opacity:1}50%{opacity:.4}}.inventory-list{list-style:none}.inventory-item{display:flex;align-items:center;justify-content:space-between;padding:14px 20px;border-bottom:1px solid var(--color-border);gap:12px}.inventory-item:last-child{border-bottom:none}.inventory-item-info{flex:1;min-width:0}.inventory-item-title{font-weight:500;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.inventory-item-isbn{font-family:monospace;font-size:.78rem;color:var(--color-text-secondary);margin-top:2px}.status-dot{flex-shrink:0;width:12px;height:12px;border-radius:50%}.status-dot--available{background:var(--color-success)}.status-dot--unavailable{background:var(--color-warning)}.stat-item--clickable{background:none;border:none;font-family:var(--font);cursor:pointer;padding:4px 8px;border-radius:var(--radius-sm);transition:background .15s}.stat-item--clickable:hover{background:var(--color-bg)}.stat-item--clickable .stat-value{text-decoration:underline;text-decoration-style:dotted;text-underline-offset:3px}.pagination{display:flex;align-items:center;justify-content:space-between;gap:12px;margin-top:16px}.pagination .btn{width:auto;flex:1}.menu-btn--studentqr{width:100%;margin-top:12px;flex-direction:row;justify-content:center;padding:16px 12px;border-color:#7c3aed;color:#7c3aed}.student-qr-card{background:var(--color-surface);border:1px solid var(--color-border);border-radius:var(--radius);padding:16px;box-shadow:var(--shadow)}.student-qr-card__header{display:flex;align-items:flex-start;justify-content:space-between;gap:12px;margin-bottom:4px}.student-qr-card__name{font-size:1.25rem;font-weight:700;color:var(--color-text)}.student-qr-card__class{font-size:.9rem;color:var(--color-text-secondary);margin-top:2px}.student-qr-card__books{margin-top:14px;border-top:1px solid var(--color-border);padding-top:12px}.overdue-badge{display:inline-flex;align-items:center;background:#fef2f2;color:var(--color-danger);border:1px solid #fecaca;border-radius:999px;padding:3px 10px;font-size:.78rem;font-weight:600;white-space:nowrap;flex-shrink:0}.checked-out-list{list-style:none;display:flex;flex-direction:column;gap:6px}.checked-out-item{display:flex;align-items:baseline;justify-content:space-between;gap:8px;font-size:.88rem;padding:6px 0;border-bottom:1px solid var(--color-border)}.checked-out-item:last-child{border-bottom:none}.checked-out-item--overdue .checked-out-item__title{color:var(--color-danger)}.checked-out-item--overdue .checked-out-item__due{color:var(--color-danger);font-weight:600}.checked-out-item__title{flex:1;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;color:var(--color-text)}.checked-out-item__due{font-size:.78rem;color:var(--color-text-secondary);white-space:nowrap;flex-shrink:0}.student-qr-pill{display:inline-flex;align-items:center;gap:8px;background:var(--color-surface);border:1px solid var(--color-border);border-radius:999px;padding:6px 14px;box-shadow:var(--shadow)}.student-qr-pill__name{font-weight:600;font-size:.95rem;color:var(--color-text)}.student-qr-pill__class{font-size:.82rem;color:var(--color-text-secondary)}.scanner-crosshair--qr{width:200px;height:200px}.mb-8{margin-bottom:8px}