/* ============================================
   Books Page - Elegant Dark Theme
   ============================================ */

:root {
    /* Color palette - sophisticated dark */
    --bg-primary: #0f0f0f;
    --bg-secondary: #1a1a1a;
    --bg-tertiary: #242424;
    --bg-card: #1e1e1e;

    --text-primary: #f5f5f5;
    --text-secondary: #a0a0a0;
    --text-muted: #666666;

    --accent: #c9a962;
    --accent-soft: rgba(201, 169, 98, 0.15);
    --accent-hover: #d4b872;

    --border: #2a2a2a;
    --border-light: #333333;

    /* Typography */
    --font-serif: 'Cormorant Garamond', Georgia, serif;
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;

    /* Spacing */
    --space-xs: 0.25rem;
    --space-sm: 0.5rem;
    --space-md: 1rem;
    --space-lg: 1.5rem;
    --space-xl: 2rem;
    --space-2xl: 3rem;
    --space-3xl: 4rem;

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 250ms ease;
    --transition-slow: 400ms ease;

    /* Book cover dimensions */
    --cover-width: 200px;
    --cover-height: 300px;
}

/* ============================================
   Reset & Base
   ============================================ */

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

html {
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

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

a {
    color: inherit;
    text-decoration: none;
}

button {
    font-family: inherit;
    cursor: pointer;
    border: none;
    background: none;
}

/* ============================================
   Container
   ============================================ */

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--space-lg) var(--space-lg) var(--space-3xl);
}

@media (min-width: 768px) {
    .container {
        padding: var(--space-2xl) var(--space-xl) var(--space-3xl);
    }
}

/* ============================================
   Header
   ============================================ */

.header {
    margin-bottom: var(--space-2xl);
}

.back-link {
    display: inline-flex;
    align-items: center;
    gap: var(--space-sm);
    color: var(--text-secondary);
    font-size: 0.875rem;
    font-weight: 500;
    margin-bottom: var(--space-xl);
    transition: color var(--transition-fast);
}

.back-link:hover {
    color: var(--text-primary);
}

.back-link svg {
    width: 18px;
    height: 18px;
}

.header-content {
    text-align: center;
    max-width: 600px;
    margin: 0 auto;
}

.header h1 {
    font-family: var(--font-serif);
    font-size: clamp(2.5rem, 8vw, 4rem);
    font-weight: 500;
    letter-spacing: -0.02em;
    margin-bottom: var(--space-md);
    color: var(--text-primary);
}

.subtitle {
    font-size: 1.125rem;
    color: var(--text-secondary);
    font-weight: 300;
}

/* ============================================
   Stats Overview
   ============================================ */

.stats-overview {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-md);
    margin-bottom: var(--space-2xl);
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.stat-card {
    text-align: center;
    padding: var(--space-lg) var(--space-md);
    background: var(--bg-secondary);
    border-radius: 12px;
    border: 1px solid var(--border);
}

.stat-card.total {
    background: linear-gradient(135deg, var(--accent-soft), transparent);
    border-color: rgba(201, 169, 98, 0.3);
}

.stat-number {
    display: block;
    font-family: var(--font-serif);
    font-size: 2rem;
    font-weight: 600;
    color: var(--text-primary);
    line-height: 1.2;
}

.stat-card.total .stat-number {
    color: var(--accent);
}

.stat-label {
    display: block;
    font-size: 0.75rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-top: var(--space-xs);
}

@media (max-width: 480px) {
    .stats-overview {
        grid-template-columns: 1fr;
        gap: var(--space-sm);
    }

    .stat-card {
        display: flex;
        align-items: center;
        justify-content: space-between;
        padding: var(--space-md);
    }

    .stat-number {
        font-size: 1.5rem;
    }

    .stat-label {
        margin-top: 0;
    }
}

/* ============================================
   Tabs
   ============================================ */

.tabs {
    display: flex;
    justify-content: center;
    gap: var(--space-sm);
    margin-bottom: var(--space-2xl);
    padding: var(--space-xs);
    background: var(--bg-secondary);
    border-radius: 10px;
    max-width: 320px;
    margin-left: auto;
    margin-right: auto;
}

.tab {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    padding: var(--space-sm) var(--space-lg);
    border-radius: 8px;
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-secondary);
    transition: all var(--transition-fast);
    flex: 1;
    justify-content: center;
}

.tab:hover {
    color: var(--text-primary);
}

.tab.active {
    background: var(--bg-tertiary);
    color: var(--text-primary);
}

.tab-count {
    font-size: 0.75rem;
    padding: 2px 8px;
    background: var(--bg-tertiary);
    border-radius: 12px;
    color: var(--text-muted);
}

.tab.active .tab-count {
    background: var(--accent-soft);
    color: var(--accent);
}

/* ============================================
   Tab Content
   ============================================ */

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
    animation: fadeIn var(--transition-base);
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

/* ============================================
   Year Sections
   ============================================ */

.year-section {
    margin-bottom: var(--space-3xl);
}

.year-header {
    display: flex;
    align-items: baseline;
    gap: var(--space-md);
    margin-bottom: var(--space-xl);
    padding-bottom: var(--space-md);
    border-bottom: 1px solid var(--border);
}

.year-title {
    font-family: var(--font-serif);
    font-size: 2rem;
    font-weight: 500;
    color: var(--text-primary);
}

.year-count {
    font-size: 0.875rem;
    color: var(--text-muted);
}

/* ============================================
   Books Grid
   ============================================ */

.books-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(var(--cover-width), 1fr));
    gap: var(--space-lg);
    justify-items: center;
}

@media (min-width: 640px) {
    .books-grid {
        gap: var(--space-xl);
        justify-items: start;
    }
}

/* ============================================
   Book Card
   ============================================ */

.book-card {
    width: var(--cover-width);
}

.book-cover-wrapper {
    position: relative;
    width: var(--cover-width);
    height: var(--cover-height);
    border-radius: 4px;
    overflow: hidden;
    background: var(--bg-tertiary);
    box-shadow:
        0 4px 6px rgba(0, 0, 0, 0.3),
        0 1px 3px rgba(0, 0, 0, 0.2);
    transition: all var(--transition-base);
}

.book-card:hover .book-cover-wrapper {
    box-shadow:
        0 8px 16px rgba(0, 0, 0, 0.4),
        0 2px 6px rgba(0, 0, 0, 0.3);
}

.book-cover {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: opacity var(--transition-base);
}

.book-cover.loading {
    opacity: 0;
}

.book-cover.loaded {
    opacity: 1;
}

.book-cover.error {
    display: none;
}

/* Placeholder for missing covers */
.book-placeholder {
    position: absolute;
    inset: 0;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: var(--space-md);
    background: linear-gradient(145deg, #2a2a2a 0%, #1a1a1a 100%);
    text-align: center;
    border: 1px solid var(--border-light);
}

.book-placeholder.hidden {
    display: none;
}

.placeholder-icon {
    display: none;
}

.placeholder-title {
    font-family: var(--font-serif);
    font-size: 0.85rem;
    font-weight: 500;
    font-style: italic;
    color: var(--text-secondary);
    line-height: 1.4;
    display: -webkit-box;
    -webkit-line-clamp: 5;
    -webkit-box-orient: vertical;
    overflow: hidden;
    padding: 0 var(--space-xs);
}

/* Book spine effect */
.book-cover-wrapper::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 3px;
    background: linear-gradient(
        to right,
        rgba(0, 0, 0, 0.3),
        rgba(0, 0, 0, 0.1),
        transparent
    );
    z-index: 1;
}

/* Book title below cover */
.book-title {
    margin-top: var(--space-sm);
    font-size: 0.8rem;
    font-weight: 400;
    color: var(--text-secondary);
    line-height: 1.4;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
    transition: color var(--transition-fast);
}

.book-card:hover .book-title {
    color: var(--text-primary);
}

.book-author {
    font-size: 0.75rem;
    color: var(--text-muted);
    margin-top: 2px;
    font-style: italic;
    display: -webkit-box;
    -webkit-line-clamp: 1;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.book-date {
    font-size: 0.7rem;
    color: var(--text-muted);
    margin-top: 2px;
}

/* ============================================
   Loading State
   ============================================ */

.loading-state {
    text-align: center;
    padding: var(--space-3xl);
    color: var(--text-secondary);
}

.loading-spinner {
    width: 40px;
    height: 40px;
    border: 3px solid var(--border);
    border-top-color: var(--accent);
    border-radius: 50%;
    margin: 0 auto var(--space-md);
    animation: spin 1s linear infinite;
}

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

/* ============================================
   Empty State
   ============================================ */

.empty-state {
    text-align: center;
    padding: var(--space-3xl);
    color: var(--text-secondary);
}

.empty-icon {
    font-size: 3rem;
    margin-bottom: var(--space-md);
    opacity: 0.5;
}

/* ============================================
   Footer
   ============================================ */

.footer {
    margin-top: var(--space-3xl);
    padding-top: var(--space-xl);
    border-top: 1px solid var(--border);
    text-align: center;
}

.footer p {
    font-size: 0.875rem;
    color: var(--text-muted);
}

.footer a {
    color: var(--text-secondary);
    transition: color var(--transition-fast);
}

.footer a:hover {
    color: var(--accent);
}

/* ============================================
   Responsive Adjustments
   ============================================ */

@media (max-width: 768px) {
    :root {
        --cover-width: 160px;
        --cover-height: 240px;
    }

    .books-grid {
        gap: var(--space-md);
    }

    .year-title {
        font-size: 1.75rem;
    }
}

@media (max-width: 480px) {
    :root {
        --cover-width: 130px;
        --cover-height: 195px;
    }

    .container {
        padding: var(--space-md) var(--space-md) var(--space-2xl);
    }

    .books-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: var(--space-sm);
        justify-items: center;
    }

    .book-card {
        width: 100%;
        max-width: var(--cover-width);
    }

    .book-cover-wrapper {
        width: 100%;
        max-width: var(--cover-width);
    }

    .year-title {
        font-size: 1.5rem;
    }

    .year-header {
        margin-bottom: var(--space-md);
    }

    .book-title {
        font-size: 0.75rem;
    }

    .book-author {
        font-size: 0.7rem;
    }

    .subtitle {
        font-size: 1rem;
    }

    .tabs {
        max-width: 100%;
    }

    .back-link {
        margin-bottom: var(--space-md);
    }
}

/* ============================================
   Print Styles
   ============================================ */

@media print {
    body {
        background: white;
        color: black;
    }

    .back-link,
    .tabs,
    .footer {
        display: none;
    }

    .book-cover-wrapper {
        box-shadow: none;
        border: 1px solid #ddd;
    }
}