/* MAIN STYLES */
:root {
    --bg-primary: #f8fafc;
    --bg-secondary: #ffffff;
    --bg-card: #ffffff;
    --text-primary: #0f172a;
    --text-secondary: #334155;
    --text-muted: #64748b;
    --border-light: #e2e8f0;
    --border-medium: #cbd5e1;
    --accent-blue: #2563eb;
    --accent-blue-light: #3b82f6;
    --accent-green: #16a34a;
    --accent-amber: #d97706;
    --accent-purple: #7c3aed;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.05), 0 1px 2px rgba(0,0,0,0.1);
    --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.05), 0 2px 4px -1px rgba(0,0,0,0.03);
    --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.05), 0 4px 6px -2px rgba(0,0,0,0.02);
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif;
    --font-mono: 'SF Mono', 'Menlo', 'Monaco', 'Cascadia Code', 'Consolas', monospace;
    --spacing-1: 0.25rem;
    --spacing-2: 0.5rem;
    --spacing-3: 0.75rem;
    --spacing-4: 1rem;
    --spacing-5: 1.25rem;
    --spacing-6: 1.5rem;
    --spacing-8: 2rem;
    --spacing-10: 2.5rem;
    --spacing-12: 3rem;
    --spacing-16: 4rem;
}

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

html, body {
    font-family: var(--font-sans);
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.5;
    width: 100%;
    min-height: 100vh;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* TYPOGRAPHY */
h1, h2, h3, h4, h5, h6 {
    font-weight: 500;
    line-height: 1.2;
    letter-spacing: -0.01em;
}

h1 { font-size: 2.5rem; font-weight: 600; }
h2 { font-size: 2rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }

p {
    color: var(--text-secondary);
    line-height: 1.6;
}

/* HEADER */
header {
    background: var(--bg-secondary);
    color: var(--text-primary);
    padding: var(--spacing-8) var(--spacing-4);
    text-align: center;
    position: relative;
    width: 100%;
    border-bottom: 1px solid var(--border-light);
}

header h1 {
    margin: 0 0 var(--spacing-2) 0;
    color: var(--text-primary);
    letter-spacing: -0.02em;
    font-weight: 600;
}

header p {
    margin: 0 auto;
    color: var(--text-secondary);
    font-size: 1.1rem;
    font-weight: 400;
    max-width: 600px;
}

.header-decoration {
    height: 2px;
    background: linear-gradient(90deg, transparent, var(--accent-blue-light), transparent);
    width: 120px;
    margin: var(--spacing-4) auto 0;
}

/* NAVIGATION */
button.openbtn {
    position: absolute;
    top: 1.8rem;
    left: 2rem;
    font-size: 0.95rem;
    cursor: pointer;
    background: var(--bg-secondary);
    color: var(--text-secondary);
    padding: 0.5rem 1rem;
    border: 1px solid var(--border-light);
    border-radius: 20px;
    z-index: 100;
    transition: all 0.2s ease;
    font-weight: 450;
    box-shadow: var(--shadow-sm);
}

button.openbtn:hover {
    background: var(--bg-primary);
    border-color: var(--border-medium);
    color: var(--text-primary);
}

nav.sidenav {
    height: 100vh;
    width: 0;
    position: fixed;
    top: 0;
    left: 0;
    background: var(--bg-secondary);
    overflow-x: hidden;
    transition: width 0.3s ease;
    padding-top: 60px;
    box-shadow: var(--shadow-lg);
    border-right: 1px solid var(--border-light);
    z-index: 1000;
}

nav.sidenav.active {
    width: 280px;
}

button.closebtn {
    position: absolute;
    top: 12px;
    right: 20px;
    font-size: 24px;
    color: var(--text-muted);
    background: none;
    border: none;
    cursor: pointer;
    padding: var(--spacing-2);
}

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

nav.sidenav ul {
    list-style: none;
    padding: 0 0 var(--spacing-4) 0;
    margin: 0;
}

.category-title {
    padding: var(--spacing-5) var(--spacing-4) var(--spacing-2);
    font-size: 0.7rem;
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

nav.sidenav ul li a {
    color: var(--text-secondary);
    text-decoration: none;
    padding: var(--spacing-2) var(--spacing-4);
    margin: 0 var(--spacing-2);
    display: block;
    transition: all 0.2s ease;
    border-radius: var(--radius-sm);
    font-weight: 400;
    font-size: 0.9rem;
}

nav.sidenav ul li a:hover {
    background: var(--bg-primary);
    color: var(--text-primary);
}

nav.sidenav ul li a[aria-current="page"] {
    background: var(--bg-primary);
    color: var(--accent-blue);
    font-weight: 500;
}

/* MAIN CONTENT */
main {
    padding: var(--spacing-8) var(--spacing-4);
    width: 100%;
    max-width: 1280px;
    margin: 0 auto;
}

/* INTRO SECTION */
.intro-section {
    text-align: center;
    max-width: 700px;
    margin: 0 auto var(--spacing-12);
}

.intro-section h2 {
    font-size: 2.2rem;
    color: var(--text-primary);
    margin-bottom: var(--spacing-3);
    font-weight: 600;
}

.intro-section p {
    font-size: 1.1rem;
    color: var(--text-secondary);
    line-height: 1.6;
}

/* CATEGORY STATS */
.category-stats {
    display: flex;
    justify-content: center;
    gap: var(--spacing-3);
    margin-top: var(--spacing-5);
}

.stat-badge {
    background: var(--bg-secondary);
    color: var(--text-secondary);
    padding: 0.3rem 1rem;
    border-radius: 30px;
    font-size: 0.85rem;
    font-weight: 450;
    border: 1px solid var(--border-light);
    box-shadow: var(--shadow-sm);
}

/* BOOK SECTIONS */
.book-section {
    margin-bottom: var(--spacing-12);
}

.section-header {
    text-align: center;
    margin-bottom: var(--spacing-6);
    padding-bottom: var(--spacing-3);
    border-bottom: 1px solid var(--border-light);
}

.section-header h2 {
    font-size: 1.8rem;
    color: var(--text-primary);
    margin-bottom: var(--spacing-1);
    font-weight: 500;
}

.section-header p {
    font-size: 1rem;
    color: var(--text-muted);
}

/* BOOK GRID */
.book-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: var(--spacing-6);
    justify-items: center;
}

/* BOOK CARD */
.book-card {
    display: flex;
    flex-direction: column;
    background: var(--bg-card);
    border: 1px solid var(--border-light);
    border-radius: var(--radius-md);
    overflow: hidden;
    text-decoration: none;
    color: inherit;
    transition: all 0.2s ease;
    position: relative;
    height: 100%;
    width: 100%;
    max-width: 220px;
    box-shadow: var(--shadow-sm);
}

.book-card:hover {
    transform: translateY(-2px);
    border-color: var(--border-medium);
    box-shadow: var(--shadow-md);
}

.book-card img {
    width: 100%;
    aspect-ratio: 2/3;
    object-fit: cover;
    display: block;
    background: var(--bg-primary);
}

.book-title {
    padding: var(--spacing-3) var(--spacing-3) var(--spacing-2);
    text-align: center;
}

.book-title h3 {
    font-size: 1rem;
    font-weight: 550;
    color: var(--text-primary);
    margin-bottom: 0.15rem;
    line-height: 1.3;
}

.book-subtitle {
    font-size: 0.85rem;
    color: var(--text-muted);
    font-weight: 400;
    display: block;
}

.book-tags {
    padding: 0 var(--spacing-3) var(--spacing-3);
    display: flex;
    flex-wrap: wrap;
    gap: 0.3rem;
    justify-content: center;
}

.book-tag {
    background: var(--bg-primary);
    color: var(--text-secondary);
    padding: 0.15rem 0.5rem;
    border-radius: 20px;
    font-size: 0.65rem;
    font-weight: 450;
    border: 1px solid var(--border-light);
}

/* RATING BADGES */
.rating-badge {
    position: absolute;
    top: 10px;
    right: 10px;
    width: 36px;
    height: 36px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 550;
    font-size: 0.85rem;
    color: white;
    box-shadow: var(--shadow-sm);
    border: 2px solid var(--bg-card);
    z-index: 2;
}

.rating-10 { background: #059669; }
.rating-9 { background: #10b981; }
.rating-8 { background: #2563eb; }
.rating-7 { background: #7c3aed; }
.rating-6 { background: #d97706; }
.rating-5 { background: #dc2626; }
.rating-4 { background: #b91c1c; }
.rating-3 { background: #991b1b; }
.rating-2 { background: #7f1d1d; }
.rating-1 { background: #581c1c; }

/* HOMEPAGE CATEGORY GRID */
.home-intro {
    text-align: center;
    font-size: 1.2rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-10);
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.category-section {
    margin-bottom: var(--spacing-10);
}

.category-section h2 {
    font-size: 1.6rem;
    font-weight: 500;
    margin-bottom: var(--spacing-5);
    color: var(--text-primary);
    border-bottom: 1px solid var(--border-light);
    padding-bottom: var(--spacing-2);
}

.category-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
    gap: var(--spacing-4);
}

.category-card {
    background: var(--bg-card);
    border: 1px solid var(--border-light);
    border-radius: var(--radius-md);
    padding: var(--spacing-4);
    text-decoration: none;
    color: var(--text-primary);
    display: flex;
    flex-direction: column;
    transition: all 0.2s ease;
    box-shadow: var(--shadow-sm);
}

.category-card:hover {
    border-color: var(--border-medium);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.category-card .title {
    font-size: 1.1rem;
    font-weight: 500;
    margin-bottom: var(--spacing-1);
    color: var(--text-primary);
}

.category-card .description {
    font-size: 0.85rem;
    color: var(--text-muted);
    line-height: 1.4;
}

/* REVIEW PAGE */
.review-main {
    max-width: 800px;
    margin: 0 auto;
    padding: var(--spacing-8) var(--spacing-4);
}

.review-header {
    margin-bottom: var(--spacing-8);
    padding-bottom: var(--spacing-6);
    border-bottom: 1px solid var(--border-light);
}

.review-meta {
    display: flex;
    align-items: flex-start;
    gap: var(--spacing-4);
    margin-bottom: var(--spacing-5);
}

.rating-display {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    font-size: 1.1rem;
    color: white;
    box-shadow: var(--shadow-sm);
    border: 2px solid var(--bg-card);
    flex-shrink: 0;
}

.rating-display.rating-8 { background: #2563eb; }

.review-title-section h1 {
    font-size: 2rem;
    color: var(--text-primary);
    margin-bottom: var(--spacing-2);
    font-weight: 600;
    line-height: 1.2;
}

.book-meta-line {
    font-size: 0.95rem;
    color: var(--text-muted);
    margin-bottom: var(--spacing-3);
}

.review-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.4rem;
}

.review-tag {
    background: var(--bg-primary);
    color: var(--text-secondary);
    padding: 0.2rem 0.7rem;
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 450;
    border: 1px solid var(--border-light);
}

.review-stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-4);
    background: var(--bg-primary);
    padding: var(--spacing-4);
    border-radius: var(--radius-md);
    border: 1px solid var(--border-light);
}

.stat-item {
    display: flex;
    flex-direction: column;
}

.stat-label {
    font-size: 0.7rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.03em;
    margin-bottom: 0.2rem;
}

.stat-value {
    font-size: 1rem;
    color: var(--text-primary);
    font-weight: 500;
}

/* BOOK COVER SECTION */
.book-cover-section {
    margin-bottom: var(--spacing-8);
}

.book-cover-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-6);
    align-items: start;
}

.book-cover-image {
    width: 100%;
    height: auto;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-light);
}

.book-quick-info {
    background: var(--bg-primary);
    border: 1px solid var(--border-light);
    border-radius: var(--radius-md);
    padding: var(--spacing-5);
}

.book-quick-info h3 {
    font-size: 1.1rem;
    font-weight: 500;
    margin-bottom: var(--spacing-3);
    color: var(--text-primary);
}

.book-quick-info ul {
    list-style: none;
    padding: 0;
}

.book-quick-info li {
    margin-bottom: var(--spacing-2);
    color: var(--text-secondary);
    font-size: 0.9rem;
    line-height: 1.5;
}

.book-quick-info strong {
    color: var(--text-primary);
    font-weight: 550;
}

/* REVIEW CONTENT */
.review-content {
    font-size: 1.05rem;
    line-height: 1.7;
    color: var(--text-secondary);
}

.review-section {
    margin-bottom: var(--spacing-8);
}

.review-section h2 {
    font-size: 1.8rem;
    color: var(--text-primary);
    margin-bottom: var(--spacing-4);
    font-weight: 600;
    letter-spacing: -0.02em;
    border-left: 4px solid var(--accent-blue-light);
    padding-left: var(--spacing-3);
}

.review-section p {
    margin-bottom: var(--spacing-4);
}

.analysis-point {
    background: var(--bg-primary);
    border-left: 3px solid var(--accent-blue-light);
    padding: var(--spacing-4) var(--spacing-5);
    margin: var(--spacing-4) 0;
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}

.analysis-point h3 {
    color: var(--text-primary);
    font-size: 1.2rem;
    margin-bottom: var(--spacing-2);
    font-weight: 550;
}

.philosophy-block {
    background: var(--bg-primary);
    border: 1px solid var(--border-light);
    padding: var(--spacing-5);
    margin: var(--spacing-4) 0;
    border-radius: var(--radius-sm);
}

.philosophy-block h3 {
    color: var(--text-primary);
    font-size: 1.2rem;
    margin-bottom: var(--spacing-2);
    font-weight: 550;
}

.critique-section {
    background: var(--bg-primary);
    border: 1px solid var(--border-light);
    padding: var(--spacing-5);
    border-radius: var(--radius-md);
}

.critique-section h2 {
    border-left-color: #dc2626;
}

.critique-point {
    margin-bottom: var(--spacing-4);
    padding-bottom: var(--spacing-4);
    border-bottom: 1px solid var(--border-light);
}

.critique-point:last-child {
    border-bottom: none;
    margin-bottom: 0;
    padding-bottom: 0;
}

.critique-point h3 {
    color: var(--text-primary);
    font-size: 1.1rem;
    margin-bottom: var(--spacing-2);
    font-weight: 550;
}

.conclusion-section {
    background: var(--bg-primary);
    border: 1px solid var(--border-light);
    padding: var(--spacing-5);
    border-radius: var(--radius-md);
}

.conclusion-section h2 {
    border-left-color: var(--accent-green);
}

.final-verdict {
    background: var(--bg-secondary);
    border: 1px solid var(--border-light);
    padding: var(--spacing-5);
    border-radius: var(--radius-md);
    margin-top: var(--spacing-5);
}

.final-verdict h3 {
    color: var(--text-primary);
    font-size: 1.2rem;
    margin-bottom: var(--spacing-2);
    font-weight: 600;
}

.final-verdict p {
    font-size: 1.1rem;
    line-height: 1.6;
    margin-bottom: 0;
}

/* RELATED BOOKS */
.related-books {
    margin-top: var(--spacing-10);
    padding-top: var(--spacing-6);
    border-top: 1px solid var(--border-light);
}

.related-books h2 {
    font-size: 1.5rem;
    color: var(--text-primary);
    margin-bottom: var(--spacing-4);
    font-weight: 500;
    border-left: 4px solid var(--accent-blue-light);
    padding-left: var(--spacing-3);
}

.related-links {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-3);
}

.related-link {
    background: var(--bg-primary);
    color: var(--text-secondary);
    text-decoration: none;
    padding: 0.5rem 1rem;
    border-radius: 30px;
    border: 1px solid var(--border-light);
    font-size: 0.9rem;
    transition: all 0.2s ease;
}

.related-link:hover {
    background: var(--bg-secondary);
    border-color: var(--border-medium);
    color: var(--text-primary);
}

/* FOOTER */
footer {
    padding: var(--spacing-8) var(--spacing-4) var(--spacing-6);
    background: var(--bg-secondary);
    border-top: 1px solid var(--border-light);
    color: var(--text-secondary);
    text-align: center;
    margin-top: var(--spacing-8);
}

.footer-decoration {
    height: 2px;
    background: linear-gradient(90deg, transparent, var(--accent-blue-light), transparent);
    width: 120px;
    margin: 0 auto var(--spacing-5);
}

footer p {
    margin-bottom: 0.3rem;
    font-size: 0.9rem;
}

.footer-quote {
    font-style: normal;
    color: var(--text-muted);
    max-width: 500px;
    margin: var(--spacing-3) auto 0;
    font-size: 0.85rem;
}

/* SCROLL TO TOP */
#scrollToTopBtn {
    display: none;
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    background: var(--bg-secondary);
    color: var(--text-secondary);
    border: 1px solid var(--border-light);
    width: 44px;
    height: 44px;
    border-radius: 50%;
    cursor: pointer;
    transition: all 0.2s ease;
    box-shadow: var(--shadow-md);
    z-index: 1000;
    display: flex;
    align-items: center;
    justify-content: center;
}

#scrollToTopBtn:hover {
    background: var(--bg-primary);
    color: var(--text-primary);
    border-color: var(--border-medium);
    transform: scale(1.05);
}

/* RESPONSIVE */
@media (max-width: 1024px) {
    main {
        padding: var(--spacing-6) var(--spacing-4);
    }
    
    h1 { font-size: 2.2rem; }
    h2 { font-size: 1.8rem; }
}

@media (max-width: 768px) {
    header h1 {
        font-size: 1.8rem;
        padding-left: 45px;
        padding-right: 45px;
    }
    
    button.openbtn {
        top: 1.5rem;
        left: 1.2rem;
        padding: 0.4rem 0.8rem;
    }
    
    main {
        padding: var(--spacing-4) var(--spacing-3);
    }
    
    .book-grid {
        grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
        gap: var(--spacing-4);
    }
    
    .book-card {
        max-width: 180px;
    }
    
    .book-card img {
        aspect-ratio: 2/3;
    }
    
    .category-grid {
        grid-template-columns: 1fr;
    }
    
    .intro-section h2 {
        font-size: 1.8rem;
    }
    
    .section-header h2 {
        font-size: 1.5rem;
    }
    
    .review-stats {
        grid-template-columns: 1fr;
        gap: var(--spacing-3);
    }
    
    .book-cover-container {
        grid-template-columns: 1fr;
        gap: var(--spacing-4);
    }
    
    .book-cover-image {
        max-width: 300px;
        margin: 0 auto;
    }
    
    .review-section h2 {
        font-size: 1.5rem;
    }
}

@media (max-width: 480px) {
    header h1 {
        font-size: 1.5rem;
    }
    
    .book-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: var(--spacing-3);
    }
    
    .book-card {
        max-width: 100%;
    }
    
    .book-title h3 {
        font-size: 0.9rem;
    }
    
    .book-subtitle {
        font-size: 0.75rem;
    }
    
    .book-tags {
        padding: 0 var(--spacing-2) var(--spacing-2);
    }
    
    .book-tag {
        font-size: 0.6rem;
    }
    
    .rating-badge {
        width: 30px;
        height: 30px;
        font-size: 0.75rem;
    }
    
    .review-meta {
        flex-direction: column;
        align-items: center;
        text-align: center;
    }
    
    .review-tags {
        justify-content: center;
    }
    
    .review-section h2 {
        font-size: 1.3rem;
    }
    
    #scrollToTopBtn {
        bottom: 1.2rem;
        right: 1.2rem;
        width: 40px;
        height: 40px;
    }
}

/* UTILITIES */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: var(--bg-primary);
}

::-webkit-scrollbar-thumb {
    background: var(--border-medium);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--text-muted);
}

button:focus,
a:focus {
    outline: 2px solid var(--accent-blue-light);
    outline-offset: 2px;
  }