/* ═══════════════════════════════════════════════
   LibraFlow — Design System
   ═══════════════════════════════════════════════ */

/* ── Google Fonts ── */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800&display=swap');
@import url('https://fonts.googleapis.com/css2?family=Noto+Sans+SC:wght@300;400;500;700&display=swap');

/* ── CSS Variables ── */
:root {
    /* Primary Palette (Deep Indigo + Gold accents) */
    --color-primary: #4F46E5;
    --color-primary-light: #818CF8;
    --color-primary-dark: #3730A3;
    --color-primary-bg: rgba(79, 70, 229, 0.08);

    --color-accent: #F59E0B;
    --color-accent-light: #FCD34D;
    --color-accent-dark: #D97706;

    /* Semantic Colors */
    --color-success: #10B981;
    --color-success-bg: rgba(16, 185, 129, 0.1);
    --color-warning: #F59E0B;
    --color-warning-bg: rgba(245, 158, 11, 0.1);
    --color-danger: #EF4444;
    --color-danger-bg: rgba(239, 68, 68, 0.1);
    --color-info: #3B82F6;
    --color-info-bg: rgba(59, 130, 246, 0.1);

    /* Neutral Scale */
    --color-bg: #F8FAFC;
    --color-bg-elevated: #FFFFFF;
    --color-bg-subtle: #F1F5F9;
    --color-border: #E2E8F0;
    --color-border-light: #F1F5F9;
    --color-text: #0F172A;
    --color-text-secondary: #64748B;
    --color-text-muted: #94A3B8;
    --color-text-inverse: #FFFFFF;

    /* Typography */
    --font-primary: 'Inter', 'Noto Sans SC', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

    /* Spacing Scale */
    --space-xs: 4px;
    --space-sm: 8px;
    --space-md: 16px;
    --space-lg: 24px;
    --space-xl: 32px;
    --space-2xl: 48px;
    --space-3xl: 64px;

    /* Border Radius */
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    --radius-full: 9999px;

    /* Shadows */
    --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
    --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.07), 0 2px 4px -2px rgba(0,0,0,0.05);
    --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.08), 0 4px 6px -4px rgba(0,0,0,0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0,0,0,0.1), 0 8px 10px -6px rgba(0,0,0,0.05);
    --shadow-glow: 0 0 20px rgba(79, 70, 229, 0.15);

    /* Transitions */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-normal: 250ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 350ms cubic-bezier(0.4, 0, 0.2, 1);

    /* Layout */
    --navbar-height: 64px;
    --sidebar-width: 260px;
    --max-content-width: 1280px;
}

/* ── Reset ── */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-primary);
    font-size: 14px;
    line-height: 1.6;
    color: var(--color-text);
    background-color: var(--color-bg);
    min-height: 100vh;
}

a {
    color: var(--color-primary);
    text-decoration: none;
    transition: color var(--transition-fast);
}
a:hover { color: var(--color-primary-dark); }

img { max-width: 100%; display: block; }

/* ── Scrollbar ── */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--color-border); border-radius: var(--radius-full); }
::-webkit-scrollbar-thumb:hover { background: var(--color-text-muted); }

/* ═══════════════════════════════════════════════
   COMPONENTS
   ═══════════════════════════════════════════════ */

/* ── Navbar (Glassmorphism) ── */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--navbar-height);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 var(--space-xl);
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(20px) saturate(180%);
    -webkit-backdrop-filter: blur(20px) saturate(180%);
    border-bottom: 1px solid var(--color-border-light);
    z-index: 1000;
    transition: box-shadow var(--transition-normal);
}
.navbar.scrolled {
    box-shadow: var(--shadow-md);
}

.navbar-brand {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    font-size: 20px;
    font-weight: 700;
    color: var(--color-primary);
}
.navbar-brand svg { width: 28px; height: 28px; }

.navbar-nav {
    display: flex;
    align-items: center;
    gap: var(--space-xs);
    list-style: none;
}
.navbar-nav .nav-link {
    display: flex;
    align-items: center;
    gap: var(--space-xs);
    padding: var(--space-sm) var(--space-md);
    border-radius: var(--radius-md);
    color: var(--color-text-secondary);
    font-weight: 500;
    font-size: 14px;
    transition: all var(--transition-fast);
}
.navbar-nav .nav-link:hover,
.navbar-nav .nav-link.active {
    color: var(--color-primary);
    background: var(--color-primary-bg);
}
.navbar-nav .nav-link svg { width: 18px; height: 18px; }

.navbar-user {
    display: flex;
    align-items: center;
    gap: var(--space-md);
}
.navbar-user .user-info {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    font-weight: 500;
    color: var(--color-text);
}
.navbar-user .user-avatar {
    width: 36px;
    height: 36px;
    border-radius: var(--radius-full);
    background: linear-gradient(135deg, var(--color-primary), var(--color-primary-light));
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 14px;
}

/* ── Page Container ── */
.page-container {
    max-width: var(--max-content-width);
    margin: 0 auto;
    padding: calc(var(--navbar-height) + var(--space-xl)) var(--space-xl) var(--space-2xl);
    min-height: 100vh;
}

.page-header {
    margin-bottom: var(--space-xl);
}
.page-header h1 {
    font-size: 28px;
    font-weight: 800;
    color: var(--color-text);
    letter-spacing: -0.5px;
}
.page-header p {
    color: var(--color-text-secondary);
    margin-top: var(--space-xs);
    font-size: 15px;
}

/* ── Cards ── */
.card {
    background: var(--color-bg-elevated);
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border-light);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-normal);
    overflow: hidden;
}
.card:hover {
    box-shadow: var(--shadow-lg);
    transform: translateY(-2px);
}
.card-body {
    padding: var(--space-lg);
}
.card-header {
    padding: var(--space-lg);
    border-bottom: 1px solid var(--color-border-light);
    font-weight: 600;
    font-size: 16px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}
.card-footer {
    padding: var(--space-md) var(--space-lg);
    border-top: 1px solid var(--color-border-light);
    background: var(--color-bg-subtle);
}

/* ── Book Card Grid ── */
.books-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
    gap: var(--space-lg);
}

.book-card {
    background: var(--color-bg-elevated);
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border-light);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-normal);
    overflow: hidden;
    cursor: pointer;
    display: flex;
    flex-direction: column;
}
.book-card:hover {
    box-shadow: var(--shadow-xl);
    transform: translateY(-4px);
    border-color: var(--color-primary-light);
}

.book-card .book-cover {
    width: 100%;
    height: 200px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    overflow: hidden;
}
.book-card .book-cover img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}
.book-card .book-cover .cover-placeholder {
    color: rgba(255,255,255,0.9);
    font-size: 20px;
    font-weight: 700;
    text-shadow: 0 2px 10px rgba(0,0,0,0.2);
    padding: var(--space-md);
    text-align: center;
    line-height: 1.4;
}

.book-card .book-info {
    padding: var(--space-md) var(--space-lg);
    flex: 1;
    display: flex;
    flex-direction: column;
}
.book-card .book-title {
    font-weight: 700;
    font-size: 16px;
    color: var(--color-text);
    margin-bottom: var(--space-xs);
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}
.book-card .book-author {
    color: var(--color-text-secondary);
    font-size: 13px;
    margin-bottom: var(--space-sm);
}
.book-card .book-meta {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-top: auto;
    padding-top: var(--space-sm);
    border-top: 1px solid var(--color-border-light);
}
.book-card .book-category {
    font-size: 12px;
    padding: 2px 10px;
    border-radius: var(--radius-full);
    background: var(--color-primary-bg);
    color: var(--color-primary);
    font-weight: 500;
}
.book-card .book-stock {
    font-size: 12px;
    font-weight: 600;
}
.book-card .book-stock.in-stock { color: var(--color-success); }
.book-card .book-stock.out-of-stock { color: var(--color-danger); }

/* ── Buttons ── */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-sm);
    padding: 10px 20px;
    font-size: 14px;
    font-weight: 600;
    font-family: var(--font-primary);
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-fast);
    white-space: nowrap;
    text-decoration: none;
    line-height: 1.4;
}
.btn:active { transform: scale(0.98); }
.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none;
}
.btn svg { width: 16px; height: 16px; }

.btn-primary {
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
    color: var(--color-text-inverse);
    box-shadow: 0 2px 8px rgba(79, 70, 229, 0.3);
}
.btn-primary:hover:not(:disabled) {
    box-shadow: 0 4px 16px rgba(79, 70, 229, 0.4);
    transform: translateY(-1px);
}

.btn-secondary {
    background: var(--color-bg-subtle);
    color: var(--color-text);
    border: 1px solid var(--color-border);
}
.btn-secondary:hover:not(:disabled) {
    background: var(--color-border);
}

.btn-success {
    background: linear-gradient(135deg, var(--color-success) 0%, #059669 100%);
    color: var(--color-text-inverse);
    box-shadow: 0 2px 8px rgba(16, 185, 129, 0.3);
}
.btn-success:hover:not(:disabled) {
    box-shadow: 0 4px 16px rgba(16, 185, 129, 0.4);
}

.btn-danger {
    background: linear-gradient(135deg, var(--color-danger) 0%, #DC2626 100%);
    color: var(--color-text-inverse);
    box-shadow: 0 2px 8px rgba(239, 68, 68, 0.3);
}
.btn-danger:hover:not(:disabled) {
    box-shadow: 0 4px 16px rgba(239, 68, 68, 0.4);
}

.btn-warning {
    background: linear-gradient(135deg, var(--color-warning) 0%, var(--color-accent-dark) 100%);
    color: var(--color-text-inverse);
}

.btn-ghost {
    background: transparent;
    color: var(--color-text-secondary);
    padding: var(--space-sm) var(--space-md);
}
.btn-ghost:hover { background: var(--color-bg-subtle); color: var(--color-text); }

.btn-sm { padding: 6px 14px; font-size: 13px; }
.btn-lg { padding: 14px 28px; font-size: 16px; }
.btn-icon {
    width: 36px;
    height: 36px;
    padding: 0;
    border-radius: var(--radius-md);
}

/* ── Forms ── */
.form-group {
    margin-bottom: var(--space-lg);
}
.form-label {
    display: block;
    font-weight: 600;
    font-size: 13px;
    margin-bottom: var(--space-sm);
    color: var(--color-text);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}
.form-control {
    width: 100%;
    padding: 12px 16px;
    font-size: 14px;
    font-family: var(--font-primary);
    border: 1.5px solid var(--color-border);
    border-radius: var(--radius-md);
    background: var(--color-bg-elevated);
    color: var(--color-text);
    transition: all var(--transition-fast);
    outline: none;
}
.form-control:focus {
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px var(--color-primary-bg);
}
.form-control::placeholder { color: var(--color-text-muted); }

select.form-control {
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' fill='%2364748B' viewBox='0 0 16 16'%3E%3Cpath d='M4.646 6.646a.5.5 0 0 1 .708 0L8 9.293l2.646-2.647a.5.5 0 0 1 .708.708l-3 3a.5.5 0 0 1-.708 0l-3-3a.5.5 0 0 1 0-.708z'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 12px center;
    padding-right: 36px;
}

textarea.form-control {
    min-height: 100px;
    resize: vertical;
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-md);
}

.form-hint {
    font-size: 12px;
    color: var(--color-text-muted);
    margin-top: 4px;
}

.form-error {
    font-size: 12px;
    color: var(--color-danger);
    margin-top: 4px;
}

/* ── Tables ── */
.table-container {
    overflow-x: auto;
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border-light);
    background: var(--color-bg-elevated);
}

table {
    width: 100%;
    border-collapse: collapse;
}
thead th {
    padding: 14px 16px;
    text-align: left;
    font-size: 12px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    color: var(--color-text-secondary);
    background: var(--color-bg-subtle);
    border-bottom: 2px solid var(--color-border);
    white-space: nowrap;
}
tbody td {
    padding: 14px 16px;
    font-size: 14px;
    border-bottom: 1px solid var(--color-border-light);
    color: var(--color-text);
}
tbody tr {
    transition: background var(--transition-fast);
}
tbody tr:hover { background: var(--color-bg-subtle); }
tbody tr:last-child td { border-bottom: none; }

/* ── Badges / Tags ── */
.badge {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    padding: 4px 10px;
    font-size: 12px;
    font-weight: 600;
    border-radius: var(--radius-full);
    white-space: nowrap;
}
.badge-success { background: var(--color-success-bg); color: var(--color-success); }
.badge-warning { background: var(--color-warning-bg); color: var(--color-accent-dark); }
.badge-danger { background: var(--color-danger-bg); color: var(--color-danger); }
.badge-info { background: var(--color-info-bg); color: var(--color-info); }
.badge-default { background: var(--color-bg-subtle); color: var(--color-text-secondary); }
.badge-primary { background: var(--color-primary-bg); color: var(--color-primary); }

/* ── Search Bar ── */
.search-bar {
    display: flex;
    gap: var(--space-md);
    margin-bottom: var(--space-xl);
    flex-wrap: wrap;
    align-items: center;
}
.search-input-wrapper {
    position: relative;
    flex: 1;
    min-width: 250px;
}
.search-input-wrapper svg {
    position: absolute;
    left: 14px;
    top: 50%;
    transform: translateY(-50%);
    width: 18px;
    height: 18px;
    color: var(--color-text-muted);
}
.search-input-wrapper input {
    padding-left: 42px;
}

/* ── Pagination ── */
.pagination {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-xs);
    margin-top: var(--space-xl);
}
.pagination .page-btn {
    min-width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    background: var(--color-bg-elevated);
    color: var(--color-text-secondary);
    font-weight: 500;
    font-size: 13px;
    cursor: pointer;
    transition: all var(--transition-fast);
    font-family: var(--font-primary);
}
.pagination .page-btn:hover { border-color: var(--color-primary); color: var(--color-primary); }
.pagination .page-btn.active {
    background: var(--color-primary);
    border-color: var(--color-primary);
    color: white;
}
.pagination .page-btn:disabled {
    opacity: 0.4;
    cursor: not-allowed;
}
.pagination .page-info {
    font-size: 13px;
    color: var(--color-text-muted);
    margin: 0 var(--space-md);
}

/* ── Toast Notifications ── */
.toast-container {
    position: fixed;
    top: calc(var(--navbar-height) + var(--space-md));
    right: var(--space-xl);
    z-index: 9999;
    display: flex;
    flex-direction: column;
    gap: var(--space-sm);
}
.toast {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    padding: var(--space-md) var(--space-lg);
    background: var(--color-bg-elevated);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-xl);
    border-left: 4px solid;
    min-width: 300px;
    max-width: 420px;
    animation: toast-in 0.3s ease-out;
    font-size: 14px;
    font-weight: 500;
}
.toast.toast-success { border-left-color: var(--color-success); }
.toast.toast-error { border-left-color: var(--color-danger); }
.toast.toast-warning { border-left-color: var(--color-warning); }
.toast.toast-info { border-left-color: var(--color-info); }
.toast.toast-out { animation: toast-out 0.3s ease-in forwards; }

@keyframes toast-in {
    from { transform: translateX(100%); opacity: 0; }
    to { transform: translateX(0); opacity: 1; }
}
@keyframes toast-out {
    from { transform: translateX(0); opacity: 1; }
    to { transform: translateX(100%); opacity: 0; }
}

/* ── Modal ── */
.modal-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(4px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 5000;
    animation: fade-in 0.2s ease;
    padding: var(--space-xl);
}
.modal {
    background: var(--color-bg-elevated);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-xl);
    max-width: 560px;
    width: 100%;
    max-height: 90vh;
    overflow-y: auto;
    animation: modal-in 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
}
.modal-header {
    padding: var(--space-lg) var(--space-xl);
    border-bottom: 1px solid var(--color-border-light);
    display: flex;
    align-items: center;
    justify-content: space-between;
}
.modal-header h3 {
    font-size: 18px;
    font-weight: 700;
}
.modal-body {
    padding: var(--space-xl);
}
.modal-footer {
    padding: var(--space-md) var(--space-xl);
    border-top: 1px solid var(--color-border-light);
    display: flex;
    justify-content: flex-end;
    gap: var(--space-md);
}

@keyframes fade-in {
    from { opacity: 0; }
    to { opacity: 1; }
}
@keyframes modal-in {
    from { opacity: 0; transform: scale(0.9) translateY(20px); }
    to { opacity: 1; transform: scale(1) translateY(0); }
}

/* ── Stat Cards ── */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: var(--space-md);
    margin-bottom: var(--space-xl);
}
.stat-card {
    background: var(--color-bg-elevated);
    border-radius: var(--radius-lg);
    padding: var(--space-lg);
    border: 1px solid var(--color-border-light);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-normal);
}
.stat-card:hover { box-shadow: var(--shadow-md); }
.stat-card .stat-icon {
    width: 44px;
    height: 44px;
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: var(--space-md);
}
.stat-card .stat-icon svg { width: 22px; height: 22px; }
.stat-card .stat-value {
    font-size: 28px;
    font-weight: 800;
    color: var(--color-text);
    letter-spacing: -0.5px;
}
.stat-card .stat-label {
    font-size: 13px;
    color: var(--color-text-secondary);
    margin-top: 2px;
    font-weight: 500;
}

/* ── Empty State ── */
.empty-state {
    text-align: center;
    padding: var(--space-3xl) var(--space-xl);
    color: var(--color-text-muted);
}
.empty-state svg {
    width: 80px;
    height: 80px;
    margin: 0 auto var(--space-lg);
    opacity: 0.3;
}
.empty-state h3 {
    font-size: 18px;
    font-weight: 600;
    color: var(--color-text-secondary);
    margin-bottom: var(--space-sm);
}
.empty-state p { font-size: 14px; }

/* ── Loading Spinner ── */
.spinner {
    width: 36px;
    height: 36px;
    border: 3px solid var(--color-border);
    border-top-color: var(--color-primary);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}
.loading-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: var(--space-3xl);
    gap: var(--space-md);
    color: var(--color-text-muted);
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* ═══════════════════════════════════════════════
   AUTH PAGES (Login / Register)
   ═══════════════════════════════════════════════ */

.auth-page {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    padding: var(--space-xl);
    position: relative;
    overflow: hidden;
}
.auth-page::before {
    content: '';
    position: absolute;
    width: 600px;
    height: 600px;
    border-radius: 50%;
    background: rgba(255,255,255,0.05);
    top: -200px;
    right: -200px;
}
.auth-page::after {
    content: '';
    position: absolute;
    width: 400px;
    height: 400px;
    border-radius: 50%;
    background: rgba(255,255,255,0.03);
    bottom: -100px;
    left: -100px;
}

.auth-card {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(20px);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-xl);
    padding: var(--space-2xl);
    width: 100%;
    max-width: 440px;
    position: relative;
    z-index: 1;
    animation: modal-in 0.5s ease-out;
}
.auth-card .auth-logo {
    text-align: center;
    margin-bottom: var(--space-xl);
}
.auth-card .auth-logo h1 {
    font-size: 28px;
    font-weight: 800;
    color: var(--color-primary);
    margin-bottom: var(--space-xs);
}
.auth-card .auth-logo p {
    color: var(--color-text-secondary);
    font-size: 14px;
}
.auth-card .auth-footer {
    text-align: center;
    margin-top: var(--space-lg);
    font-size: 14px;
    color: var(--color-text-secondary);
}
.auth-card .auth-footer a {
    font-weight: 600;
}

/* ═══════════════════════════════════════════════
   BOOK DETAIL PAGE
   ═══════════════════════════════════════════════ */

.book-detail {
    display: grid;
    grid-template-columns: 300px 1fr;
    gap: var(--space-2xl);
    align-items: start;
}
.book-detail .book-cover-large {
    width: 100%;
    aspect-ratio: 3/4;
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-lg);
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    display: flex;
    align-items: center;
    justify-content: center;
}
.book-detail .book-cover-large img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}
.book-detail .book-cover-large .cover-placeholder {
    color: rgba(255,255,255,0.8);
    font-size: 28px;
    font-weight: 800;
    padding: var(--space-xl);
    text-align: center;
    line-height: 1.4;
}
.book-detail .book-info-detail h1 {
    font-size: 32px;
    font-weight: 800;
    margin-bottom: var(--space-sm);
    letter-spacing: -0.5px;
}
.book-detail .book-meta-list {
    display: flex;
    flex-direction: column;
    gap: var(--space-md);
    margin: var(--space-lg) 0;
}
.book-detail .meta-item {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    font-size: 14px;
}
.book-detail .meta-item .meta-label {
    color: var(--color-text-muted);
    min-width: 80px;
    font-weight: 500;
}
.book-detail .meta-item .meta-value {
    color: var(--color-text);
    font-weight: 500;
}
.book-detail .book-description {
    margin-top: var(--space-lg);
    padding: var(--space-lg);
    background: var(--color-bg-subtle);
    border-radius: var(--radius-md);
    line-height: 1.8;
    color: var(--color-text-secondary);
}

/* ═══════════════════════════════════════════════
   ADMIN LAYOUT
   ═══════════════════════════════════════════════ */

.admin-layout {
    display: flex;
    min-height: 100vh;
}

.admin-sidebar {
    width: var(--sidebar-width);
    background: linear-gradient(180deg, #1E1B4B 0%, #312E81 100%);
    color: white;
    position: fixed;
    top: 0;
    left: 0;
    bottom: 0;
    overflow-y: auto;
    z-index: 100;
    display: flex;
    flex-direction: column;
}
.admin-sidebar .sidebar-brand {
    padding: var(--space-xl);
    display: flex;
    align-items: center;
    gap: var(--space-md);
    font-size: 20px;
    font-weight: 700;
    border-bottom: 1px solid rgba(255,255,255,0.1);
}
.admin-sidebar .sidebar-brand svg { width: 28px; height: 28px; color: var(--color-accent); }

.admin-sidebar .sidebar-menu {
    padding: var(--space-md);
    list-style: none;
    flex: 1;
}
.admin-sidebar .menu-label {
    font-size: 11px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 1px;
    color: rgba(255,255,255,0.4);
    padding: var(--space-lg) var(--space-md) var(--space-sm);
}
.admin-sidebar .menu-item a {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    padding: 10px var(--space-md);
    border-radius: var(--radius-md);
    color: rgba(255,255,255,0.7);
    font-weight: 500;
    font-size: 14px;
    transition: all var(--transition-fast);
    margin-bottom: 2px;
}
.admin-sidebar .menu-item a svg { width: 20px; height: 20px; }
.admin-sidebar .menu-item a:hover {
    background: rgba(255,255,255,0.1);
    color: white;
}
.admin-sidebar .menu-item a.active {
    background: rgba(255,255,255,0.15);
    color: white;
}

.admin-sidebar .sidebar-footer {
    padding: var(--space-md);
    border-top: 1px solid rgba(255,255,255,0.1);
}

.admin-content {
    flex: 1;
    margin-left: var(--sidebar-width);
    padding: var(--space-xl) var(--space-2xl);
    min-height: 100vh;
    background: var(--color-bg);
}
.admin-content .admin-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: var(--space-xl);
}
.admin-content .admin-header h1 {
    font-size: 24px;
    font-weight: 800;
    letter-spacing: -0.5px;
}

/* ── Chart Container ── */
.chart-container {
    position: relative;
    height: 300px;
    padding: var(--space-lg);
}

/* ── Action Bar ── */
.action-bar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--space-md);
    margin-bottom: var(--space-lg);
    flex-wrap: wrap;
}
.action-bar .filters {
    display: flex;
    gap: var(--space-sm);
    flex-wrap: wrap;
    align-items: center;
}

/* ═══════════════════════════════════════════════
   ANIMATIONS
   ═══════════════════════════════════════════════ */

@keyframes fade-up {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

.fade-up {
    animation: fade-up 0.4s ease-out both;
}
.fade-up-delay-1 { animation-delay: 0.05s; }
.fade-up-delay-2 { animation-delay: 0.1s; }
.fade-up-delay-3 { animation-delay: 0.15s; }
.fade-up-delay-4 { animation-delay: 0.2s; }

/* ═══════════════════════════════════════════════
   RESPONSIVE
   ═══════════════════════════════════════════════ */

@media (max-width: 768px) {
    .page-container {
        padding: calc(var(--navbar-height) + var(--space-md)) var(--space-md) var(--space-xl);
    }

    .books-grid {
        grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
        gap: var(--space-md);
    }

    .book-detail {
        grid-template-columns: 1fr;
    }
    .book-detail .book-cover-large {
        max-width: 300px;
        margin: 0 auto;
    }

    .form-row {
        grid-template-columns: 1fr;
    }

    .search-bar {
        flex-direction: column;
    }
    .search-input-wrapper {
        min-width: 100%;
    }

    .navbar {
        padding: 0 var(--space-md);
    }
    .navbar-nav {
        display: none;
    }

    .admin-sidebar {
        display: none;
    }
    .admin-content {
        margin-left: 0;
        padding: var(--space-md);
    }

    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .action-bar {
        flex-direction: column;
        align-items: stretch;
    }
}

@media (max-width: 480px) {
    .stats-grid {
        grid-template-columns: 1fr;
    }
    .books-grid {
        grid-template-columns: 1fr;
    }
}

/* ── Utilities ── */
.text-center { text-align: center; }
.text-right { text-align: right; }
.mt-md { margin-top: var(--space-md); }
.mt-lg { margin-top: var(--space-lg); }
.mb-md { margin-bottom: var(--space-md); }
.mb-lg { margin-bottom: var(--space-lg); }
.flex { display: flex; }
.flex-center { display: flex; align-items: center; justify-content: center; }
.flex-between { display: flex; align-items: center; justify-content: space-between; }
.gap-sm { gap: var(--space-sm); }
.gap-md { gap: var(--space-md); }
.hidden { display: none !important; }