:root{--color-primary: #3b82f6;--color-primary-hover: #2563eb;--color-danger: #ef4444;--color-danger-text: #dc2626;--color-danger-bg: #fee2e2;--color-danger-border: #fecaca;--color-success: #16a34a;--color-success-bg: #dcfce7;--color-success-bg-light: #f0fdf4;--color-text: #333;--color-text-secondary: #666;--color-text-muted: #999;--color-text-subtle: #6b7280;--color-border: #e5e7eb;--color-border-dark: #d1d5db;--color-bg-muted: #f3f4f6;--color-disabled: #9ca3af;--space-xs: 4px;--space-sm: 8px;--space-md: 12px;--space-lg: 16px;--space-xl: 24px;--space-2xl: 40px;--radius: 4px;--transition-fast: .15s ease;--transition-normal: .3s ease}*{box-sizing:border-box;margin:0;padding:0}body{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen,Ubuntu,Cantarell,Open Sans,Helvetica Neue,sans-serif;line-height:1.5;color:var(--color-text)}.container{max-width:600px;margin:var(--space-2xl) auto;padding:20px}.container-wide{max-width:800px}.text-secondary{color:var(--color-text-secondary)}.text-muted{color:var(--color-text-muted);font-style:italic}.text-error{color:var(--color-danger)}.text-success{color:var(--color-success)}.link{color:var(--color-primary);text-decoration:none}.link:hover{text-decoration:underline}.btn{display:inline-flex;align-items:center;padding:var(--space-sm) var(--space-lg);border:none;border-radius:var(--radius);font-size:inherit;cursor:pointer;transition:background-color var(--transition-fast);text-decoration:none}.btn:disabled{cursor:not-allowed;opacity:.6}.btn-sm{padding:var(--space-xs) var(--space-md);font-size:14px}.btn-primary{background-color:var(--color-primary);color:#fff}.btn-primary:hover:not(:disabled){background-color:var(--color-primary-hover)}.btn-secondary{background-color:#fff;color:var(--color-text);border:1px solid var(--color-border-dark)}.btn-secondary:hover:not(:disabled){background-color:var(--color-bg-muted)}.card-list{list-style:none;padding:0;margin:0}.card{padding:var(--space-md);border:1px solid var(--color-border);border-radius:var(--radius);margin-bottom:var(--space-sm)}.spinner{width:32px;height:32px;border:3px solid var(--color-border);border-top-color:var(--color-primary);border-radius:50%;animation:spin .8s linear infinite}@keyframes spin{to{transform:rotate(360deg)}}.scanner-viewport{width:100%;height:400px;background-color:#000;border-radius:var(--radius);overflow:hidden}.isbn-code{font-family:monospace;font-size:14px;color:var(--color-text-secondary)}.landing-page{min-height:100vh}.landing-header{padding:var(--space-lg) var(--space-xl);border-bottom:1px solid var(--color-border)}.landing-header-content{max-width:1000px;margin:0 auto;display:flex;justify-content:space-between;align-items:center}.landing-logo{font-size:24px;font-weight:700;color:var(--color-primary);text-decoration:none}.landing-nav{display:flex;align-items:center;gap:var(--space-sm)}.nav-placeholder{width:120px;height:32px}.nav-user-email{color:var(--color-text-secondary);font-size:14px;margin-right:var(--space-sm)}.profile-dropdown{position:relative}.profile-button{width:36px;height:36px;border-radius:50%;border:1px solid var(--color-border);background:#fff;cursor:pointer;display:flex;align-items:center;justify-content:center;padding:0;transition:border-color var(--transition-fast),background-color var(--transition-fast)}.profile-button:hover{border-color:var(--color-border-dark);background-color:var(--color-bg-muted)}.profile-button svg{width:20px;height:20px;color:var(--color-text-secondary)}.profile-menu{position:absolute;top:100%;right:0;margin-top:var(--space-sm);min-width:200px;background:#fff;border:1px solid var(--color-border);border-radius:var(--radius);box-shadow:0 4px 12px #0000001a;z-index:100}.profile-menu-header{display:block;padding:var(--space-md);font-size:14px;color:var(--color-text);border-bottom:1px solid var(--color-border);text-decoration:none;font-weight:500;transition:background-color var(--transition-fast)}.profile-menu-header:hover{background-color:var(--color-bg-muted)}.profile-menu-item{display:block;width:100%;padding:var(--space-md);font-size:14px;color:var(--color-text);background:none;border:none;text-align:left;cursor:pointer;text-decoration:none;transition:background-color var(--transition-fast)}.profile-menu-item:hover{background-color:var(--color-bg-muted)}.landing-hero{max-width:700px;margin:0 auto;padding:var(--space-2xl) var(--space-xl);text-align:center}.landing-hero-title{font-size:36px;font-weight:700;line-height:1.2;margin-bottom:var(--space-lg);color:var(--color-text)}.landing-hero-subtitle{font-size:18px;color:var(--color-text-secondary);margin-bottom:var(--space-xl);line-height:1.6}.landing-hero-actions{display:flex;justify-content:center;gap:var(--space-md)}.landing-section-title{font-size:24px;font-weight:600;text-align:center;margin-bottom:var(--space-sm)}.landing-section-subtitle{text-align:center;color:var(--color-text-secondary);margin-bottom:var(--space-xl)}.landing-scanner-section{max-width:700px;margin:0 auto;padding:var(--space-2xl) var(--space-xl);border-top:1px solid var(--color-border)}.landing-scanner-container{margin-bottom:var(--space-xl)}.landing-scanner-placeholder{display:flex;flex-direction:column;align-items:center;justify-content:center;height:300px;background-color:var(--color-bg-muted);border-radius:var(--radius);text-align:center;padding:var(--space-xl)}.landing-scanner-placeholder p{color:var(--color-text-secondary);margin-bottom:var(--space-lg)}.landing-scanner-message{position:absolute;top:50%;left:50%;transform:translate(-50%,-50%);color:#fff;text-align:center}.landing-scanner-fallback{display:flex;flex-direction:column;align-items:center;justify-content:center;height:300px;background-color:var(--color-bg-muted);border-radius:var(--radius);text-align:center;padding:var(--space-xl)}.landing-scanner-fallback-title{font-size:18px;font-weight:600;margin-bottom:var(--space-sm)}.landing-scanner-fallback-actions{display:flex;gap:var(--space-sm)}.landing-scan-results{margin-top:var(--space-xl)}.landing-scan-results h3{margin-bottom:var(--space-md)}.landing-scan-cta{margin-top:var(--space-lg);text-align:center}.landing-features{padding:var(--space-2xl) var(--space-xl);background-color:var(--color-bg-muted)}.landing-features-grid{max-width:900px;margin:0 auto;display:grid;grid-template-columns:repeat(3,1fr);gap:var(--space-xl)}.landing-feature-card{background:#fff;padding:var(--space-xl);border-radius:var(--radius);text-align:center;border:1px solid var(--color-border)}.landing-feature-icon{font-size:36px;display:block;margin-bottom:var(--space-md)}.landing-feature-title{font-size:18px;font-weight:600;margin-bottom:var(--space-sm)}.landing-feature-description{color:var(--color-text-secondary);font-size:14px;line-height:1.5}.landing-cta{max-width:700px;margin:0 auto;padding:var(--space-2xl) var(--space-xl);text-align:center}.landing-cta-title{font-size:24px;font-weight:600;margin-bottom:var(--space-lg)}.landing-cta-signin{margin-top:var(--space-lg);color:var(--color-text-secondary)}.landing-footer{padding:var(--space-xl);border-top:1px solid var(--color-border);text-align:center;color:var(--color-text-secondary);font-size:14px}@media(max-width:767px){.landing-hero-title{font-size:28px}.landing-hero-subtitle{font-size:16px}.landing-hero-actions{flex-direction:column;align-items:center}.landing-hero-actions .btn{width:100%;max-width:280px;justify-content:center}.landing-features-grid{grid-template-columns:1fr}}