/* ==================== Reset & Base ==================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* AI/Modern Color Palette - Futuristic, Tech-Inspired */
    --color-bg: #0a0e27;
    --color-bg-secondary: #111428;
    --color-white: #ffffff;
    --color-text: #e8eaf6;
    --color-text-light: #9ca3af;
    --color-primary: #00d4ff;
    --color-primary-dark: #00a8cc;
    --color-primary-glow: rgba(0, 212, 255, 0.5);
    --color-secondary: #6366f1;
    --color-accent: #8b5cf6;
    --color-accent-glow: rgba(139, 92, 246, 0.4);
    --color-border: rgba(99, 102, 241, 0.2);
    --color-success: #10b981;
    --color-error: #ef4444;
    
    /* Glassmorphism */
    --glass-bg: rgba(255, 255, 255, 0.05);
    --glass-border: rgba(255, 255, 255, 0.1);
    --glass-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.37);
    
    /* Shadows with glow */
    --shadow-sm: 0 2px 8px rgba(0, 212, 255, 0.1);
    --shadow-md: 0 4px 16px rgba(0, 212, 255, 0.2), 0 0 0 1px rgba(0, 212, 255, 0.1);
    --shadow-lg: 0 8px 32px rgba(0, 212, 255, 0.3), 0 0 0 1px rgba(0, 212, 255, 0.2);
    --shadow-glow: 0 0 20px rgba(0, 212, 255, 0.5);
    
    --border-radius: 12px;
    --border-radius-lg: 16px;
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
}

body {
    font-family: 'Inter', 'SF Pro Display', -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', sans-serif;
    background: var(--color-bg);
    background-image: 
        radial-gradient(circle at 20% 50%, rgba(0, 212, 255, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 80% 80%, rgba(139, 92, 246, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 40% 20%, rgba(99, 102, 241, 0.05) 0%, transparent 50%);
    background-attachment: fixed;
    color: var(--color-text);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    min-height: 100vh;
    position: relative;
    overflow-x: hidden;
}

/* Animated grid pattern overlay */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image: 
        linear-gradient(rgba(0, 212, 255, 0.03) 1px, transparent 1px),
        linear-gradient(90deg, rgba(0, 212, 255, 0.03) 1px, transparent 1px);
    background-size: 50px 50px;
    pointer-events: none;
    z-index: 0;
    animation: gridMove 20s linear infinite;
}

@keyframes gridMove {
    0% { transform: translate(0, 0); }
    100% { transform: translate(50px, 50px); }
}

/* ==================== Container & Layout ==================== */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
    position: relative;
    z-index: 1;
}

/* ==================== Header ==================== */
.header {
    background: var(--glass-bg);
    backdrop-filter: blur(20px) saturate(180%);
    -webkit-backdrop-filter: blur(20px) saturate(180%);
    border-bottom: 1px solid var(--glass-border);
    padding: var(--spacing-md) 0;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: var(--glass-shadow);
    position: relative;
}

.header::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 1px;
    background: linear-gradient(90deg, 
        transparent 0%, 
        var(--color-primary) 50%, 
        transparent 100%);
    opacity: 0.5;
}

.header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-accent) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    text-decoration: none;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    letter-spacing: -0.5px;
    position: relative;
}

.logo:hover {
    filter: drop-shadow(0 0 8px var(--color-primary-glow));
    transform: translateY(-1px);
}

.logo::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 0;
    height: 2px;
    background: linear-gradient(90deg, var(--color-primary), var(--color-accent));
    transition: width 0.3s ease;
}

.logo:hover::after {
    width: 100%;
}

.logo-icon {
    display: inline-block;
    width: 1.2em;
    height: 1.2em;
    background-image: url('../icon.png');
    background-size: contain;
    background-repeat: no-repeat;
    background-position: center;
    position: relative;
    vertical-align: middle;
}

.auth-section {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.user-info {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.user-info .btn {
    height: 44px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
}

.user-avatar {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    object-fit: cover;
}

.user-name {
    font-weight: 500;
}

.login-section {
    display: flex;
    align-items: center;
}

/* ==================== Buttons ==================== */
.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border: 1px solid var(--color-primary);
    border-radius: var(--border-radius);
    font-size: 1rem;
    font-weight: 600;
    text-align: center;
    text-decoration: none;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
    color: var(--color-white);
    min-height: 44px;
    min-width: 44px;
    position: relative;
    overflow: hidden;
    box-shadow: var(--shadow-sm);
}

.btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
    transition: left 0.5s;
}

.btn:hover::before {
    left: 100%;
}

.btn:hover {
    background: linear-gradient(135deg, var(--color-primary-dark) 0%, var(--color-primary) 100%);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md), var(--shadow-glow);
    border-color: var(--color-primary);
}

.btn:active {
    transform: translateY(0);
    box-shadow: var(--shadow-sm);
}

.btn-primary {
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
    border-color: var(--color-primary);
    color: var(--color-white);
}

.btn-primary:hover {
    box-shadow: var(--shadow-md), var(--shadow-glow);
}

.btn-secondary {
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border-color: var(--color-secondary);
    color: var(--color-text);
}

.btn-secondary:hover {
    background: rgba(99, 102, 241, 0.2);
    border-color: var(--color-secondary);
    box-shadow: 0 4px 16px rgba(99, 102, 241, 0.3);
}

.btn-large {
    padding: 1rem 2rem;
    font-size: 1.1rem;
}

/* ==================== Main Content ==================== */
.main {
    padding: var(--spacing-xl) 0;
    min-height: calc(100vh - 80px);
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: var(--spacing-lg);
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-accent) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    text-align: center;
    letter-spacing: -1px;
    position: relative;
    padding-bottom: var(--spacing-sm);
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 100px;
    height: 3px;
    background: linear-gradient(90deg, transparent, var(--color-primary), transparent);
    border-radius: 2px;
}

/* ==================== Search ==================== */
.search-section {
    margin-bottom: var(--spacing-lg);
}

.search-container {
    position: relative;
    max-width: 600px;
    margin: 0 auto var(--spacing-md);
}

.search-input {
    width: 100%;
    padding: 0.875rem 3rem 0.875rem 1rem;
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    font-size: 1rem;
    background: #ffffff;
    color: var(--color-text);
    transition: all 0.3s ease;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
}

.search-input:focus {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
    border-color: var(--color-primary);
    box-shadow: 0 4px 12px rgba(0, 212, 255, 0.15);
}

.search-input::placeholder {
    color: var(--color-text-light);
}

.clear-search-btn {
    position: absolute;
    right: 0.75rem;
    top: 50%;
    transform: translateY(-50%);
    background: none;
    border: none;
    color: var(--color-text-light);
    font-size: 1.25rem;
    cursor: pointer;
    padding: 0.25rem 0.5rem;
    border-radius: 50%;
    transition: all 0.2s ease;
    line-height: 1;
}

.clear-search-btn:hover {
    background: #f0f0f0;
    color: var(--color-text);
}

.search-results-info {
    text-align: center;
    margin-top: var(--spacing-sm);
    font-size: 0.9rem;
}

.results-count {
    color: var(--color-text);
    font-weight: 500;
}

.no-results {
    color: var(--color-text-light);
    font-style: italic;
}

/* ==================== Books Grid ==================== */
.books-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: var(--spacing-lg);
    margin-top: var(--spacing-lg);
}

.book-card {
    background: var(--glass-bg);
    backdrop-filter: blur(20px) saturate(180%);
    -webkit-backdrop-filter: blur(20px) saturate(180%);
    border: 1px solid var(--glass-border);
    border-radius: var(--border-radius-lg);
    overflow: hidden;
    box-shadow: var(--glass-shadow);
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    text-decoration: none;
    color: inherit;
    display: block;
    position: relative;
}

.book-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, rgba(0, 212, 255, 0.1) 0%, rgba(139, 92, 246, 0.1) 100%);
    opacity: 0;
    transition: opacity 0.4s;
    pointer-events: none;
    z-index: 0;
}

.book-card:hover::before {
    opacity: 1;
}

.book-card:hover {
    transform: translateY(-8px) scale(1.02);
    box-shadow: var(--shadow-lg), var(--shadow-glow);
    border-color: var(--color-primary);
}

.book-card > * {
    position: relative;
    z-index: 1;
}

.book-cover {
    width: 100%;
    height: 400px;
    object-fit: contain; /* zeige komplettes Cover, kein Zuschnitt */
    object-position: center;
    background-color: #f5f5f5; /* neutraler Rand-Hintergrund im Simple-Theme */
    padding: 8px; /* etwas Weißraum um das Cover */
    transition: opacity 0.3s ease-in-out;
}

/* Lazy Loading Effekte */
.book-cover:not(.loaded) {
    opacity: 0.7;
    background-color: #f5f5f5;
}

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

.book-info {
    padding: var(--spacing-md);
}

.book-title {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
    color: var(--color-text);
    transition: color 0.3s;
}

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

.book-author {
    color: var(--color-text-light);
    font-size: 0.9rem;
    margin-bottom: var(--spacing-xs);
}

.book-genre {
    color: var(--color-text-light);
    font-size: 0.85rem;
    margin-bottom: var(--spacing-sm);
}

.download-section {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-md);
}

.download-section .btn-large {
    min-width: 180px;
    text-align: center;
}

.no-downloads {
    color: var(--color-text-light);
    font-style: italic;
}

.book-price {
    font-size: 1.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-accent) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-top: var(--spacing-sm);
}

/* ==================== Book Details ==================== */
.book-details {
    max-width: 900px;
    margin: 0 auto;
}

.book-details-container {
    background: var(--glass-bg);
    backdrop-filter: blur(20px) saturate(180%);
    -webkit-backdrop-filter: blur(20px) saturate(180%);
    border: 1px solid var(--glass-border);
    border-radius: var(--border-radius-lg);
    padding: var(--spacing-xl);
    box-shadow: var(--glass-shadow);
    display: grid;
    grid-template-columns: 300px 1fr;
    gap: var(--spacing-xl);
    position: relative;
}

.book-details-container::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, rgba(0, 212, 255, 0.05) 0%, rgba(139, 92, 246, 0.05) 100%);
    border-radius: var(--border-radius-lg);
    pointer-events: none;
    z-index: 0;
}

.book-details-container > * {
    position: relative;
    z-index: 1;
}

.book-details-cover {
    width: 100%;
    height: auto;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-md);
}

.book-details-info {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.book-details-title {
    font-size: 2.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-accent) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: -1px;
}

.book-details-author {
    font-size: 1.25rem;
    color: var(--color-text-light);
}

.book-details-price {
    font-size: 2rem;
    font-weight: 600;
    color: var(--color-primary);
    margin: var(--spacing-sm) 0;
}

.book-details-description {
    font-size: 1.1rem;
    line-height: 1.8;
    color: var(--color-text);
    margin: var(--spacing-md) 0;
}

.book-details-meta {
    display: flex;
    gap: var(--spacing-md);
    color: var(--color-text-light);
    font-size: 0.9rem;
}

/* ==================== Ratings ==================== */
.book-rating-display {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin: var(--spacing-sm) 0;
}

.book-rating-mini {
    display: flex;
    align-items: center;
    gap: 0.3rem;
    margin: 0.5rem 0;
}

.stars-display,
.stars-rating,
.stars-display-mini {
    display: inline-flex;
    gap: 0.2rem;
}

.stars-display .star,
.stars-rating .star,
.stars-display-mini .star {
    font-size: 1.5rem;
    color: #ddd;
    cursor: pointer;
    transition: color 0.2s;
    user-select: none;
}

.stars-display-mini .star {
    font-size: 1rem;
}

.stars-display .star.active,
.stars-rating .star.active,
.stars-rating .star.hover,
.stars-display-mini .star.active {
    color: #ffc107;
}

.rating-text {
    color: var(--color-text-light);
    font-size: 0.9rem;
}

.rating-text-mini {
    color: var(--color-text-light);
    font-size: 0.85rem;
    font-weight: 500;
}

.rating-section {
    margin-top: var(--spacing-lg);
    padding-top: var(--spacing-lg);
    border-top: 1px solid var(--color-border);
}

.rating-section h3 {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-sm);
    color: var(--color-text);
}

.rating-comment-form {
    margin-top: var(--spacing-md);
}

.rating-comment-input {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    font-size: 1rem;
    font-family: inherit;
    resize: vertical;
    background: #ffffff;
    color: var(--color-text);
}

.rating-comment-input:focus {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
    border-color: var(--color-primary);
}

.rating-message {
    margin-top: var(--spacing-sm);
    font-size: 0.9rem;
    min-height: 1.5rem;
}

.rating-message.success {
    color: #10b981;
}

.rating-message.error {
    color: #ef4444;
}

/* ==================== Reviews List ==================== */
.reviews-section {
    margin-top: var(--spacing-xl);
    padding-top: var(--spacing-lg);
    border-top: 1px solid var(--color-border);
}

.reviews-section h3 {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-md);
    color: var(--color-text);
}

.reviews-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.review-item {
    background: #ffffff;
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    padding: var(--spacing-md);
}

.review-header {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-sm);
    flex-wrap: wrap;
}

.review-user {
    font-weight: 600;
    color: var(--color-text);
}

.review-stars {
    display: inline-flex;
    gap: 0.1rem;
}

.review-stars .star {
    font-size: 1rem;
    color: #ddd;
}

.review-stars .star.active {
    color: #ffc107;
}

.review-date {
    color: var(--color-text-light);
    font-size: 0.85rem;
    margin-left: auto;
}

.review-comment {
    color: var(--color-text);
    line-height: 1.6;
    margin-top: var(--spacing-sm);
    white-space: pre-wrap;
}

.no-reviews {
    color: var(--color-text-light);
    font-style: italic;
    text-align: center;
    padding: var(--spacing-md);
}

.login-prompt {
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid var(--color-primary);
    border-radius: var(--border-radius);
    padding: var(--spacing-md);
    margin: var(--spacing-md) 0;
    text-align: center;
    box-shadow: var(--shadow-sm);
}

.login-prompt p {
    margin-bottom: var(--spacing-sm);
}

/* ==================== Auth Pages (Login/Register) ==================== */
.auth-container {
    max-width: 450px;
    margin: 0 auto;
    background: var(--glass-bg);
    backdrop-filter: blur(20px) saturate(180%);
    -webkit-backdrop-filter: blur(20px) saturate(180%);
    border: 1px solid var(--glass-border);
    padding: var(--spacing-xl);
    border-radius: var(--border-radius-lg);
    box-shadow: var(--glass-shadow);
    position: relative;
    overflow: hidden;
}

.auth-container::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, rgba(0, 212, 255, 0.1) 0%, transparent 70%);
    animation: pulse 4s ease-in-out infinite;
}

@keyframes pulse {
    0%, 100% { transform: scale(1); opacity: 0.5; }
    50% { transform: scale(1.1); opacity: 0.8; }
}

.auth-container > * {
    position: relative;
    z-index: 1;
}

.auth-container h1 {
    font-size: 2rem;
    margin-bottom: var(--spacing-lg);
    text-align: center;
    color: var(--color-text);
}

.auth-form {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.form-group label {
    font-weight: 500;
    color: var(--color-text);
    font-size: 0.9rem;
}

.form-group input {
    padding: 0.75rem;
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid var(--glass-border);
    border-radius: var(--border-radius);
    font-size: 1rem;
    font-family: inherit;
    color: var(--color-text);
    transition: all 0.3s;
}

.form-group input::placeholder {
    color: var(--color-text-light);
}

.form-group input:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px var(--color-primary-glow), var(--shadow-sm);
    background: rgba(255, 255, 255, 0.08);
}

.form-group small {
    color: var(--color-text-light);
    font-size: 0.85rem;
}

.auth-switch {
    text-align: center;
    margin-top: var(--spacing-md);
    color: var(--color-text-light);
}

.auth-switch a {
    color: var(--color-primary);
    text-decoration: none;
    font-weight: 500;
}

.auth-switch a:hover {
    text-decoration: underline;
}

/* ==================== Success Page ==================== */
.success-container {
    max-width: 600px;
    margin: 0 auto;
    text-align: center;
    background: var(--glass-bg);
    backdrop-filter: blur(20px) saturate(180%);
    -webkit-backdrop-filter: blur(20px) saturate(180%);
    border: 1px solid var(--glass-border);
    padding: var(--spacing-xl);
    border-radius: var(--border-radius-lg);
    box-shadow: var(--glass-shadow);
    position: relative;
}

.success-container::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, rgba(0, 212, 255, 0.05) 0%, rgba(139, 92, 246, 0.05) 100%);
    border-radius: var(--border-radius-lg);
    pointer-events: none;
    z-index: 0;
}

.success-container > * {
    position: relative;
    z-index: 1;
}

.success-icon {
    width: 80px;
    height: 80px;
    border-radius: 50%;
    background-color: var(--color-success);
    color: var(--color-white);
    font-size: 3rem;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto var(--spacing-lg);
}

.success-container h1 {
    font-size: 2rem;
    margin-bottom: var(--spacing-sm);
    color: var(--color-text);
}

.success-message {
    font-size: 1.1rem;
    color: var(--color-text-light);
    margin-bottom: var(--spacing-lg);
}

.back-link {
    display: inline-block;
    margin-top: var(--spacing-lg);
    color: var(--color-primary);
    text-decoration: none;
    transition: opacity 0.2s;
}

.back-link:hover {
    opacity: 0.8;
    text-decoration: underline;
}

/* ==================== Loading & Error ==================== */
.loading {
    text-align: center;
    padding: var(--spacing-xl);
    color: var(--color-text-light);
    font-size: 1.1rem;
}

.error {
    color: var(--color-error);
    padding: var(--spacing-md);
    background: rgba(239, 68, 68, 0.1);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid rgba(239, 68, 68, 0.3);
    border-radius: var(--border-radius);
    margin: var(--spacing-md) 0;
    box-shadow: 0 4px 16px rgba(239, 68, 68, 0.2);
}

/* ==================== Responsive ==================== */
@media (max-width: 768px) {
    .books-grid {
        grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
        gap: var(--spacing-md);
    }
    
    .book-details-container {
        grid-template-columns: 1fr;
        padding: var(--spacing-md);
    }
    
    .book-details-title {
        font-size: 1.75rem;
    }
    
    .header .container {
        flex-direction: column;
        gap: var(--spacing-sm);
    }
    
    .user-info {
        flex-wrap: wrap;
        gap: var(--spacing-sm);
    }
    
    .user-info #user-name {
        font-size: 0.9rem;
        white-space: nowrap;
    }
    
    .user-info .btn {
        height: 38px;
        padding: 0.5rem 1rem;
        font-size: 0.9rem;
    }
    
    .section-title {
        font-size: 1.5rem;
    }
}

@media (max-width: 480px) {
    .books-grid {
        grid-template-columns: 1fr;
    }
    
    .container {
        padding: 0 var(--spacing-sm);
    }
    
    .main {
        padding: var(--spacing-md) 0;
    }
    
    .user-info {
        gap: 0.6rem;
    }
    
    .user-info #user-name {
        font-size: 0.85rem;
    }
    
    .user-info .btn {
        height: 36px;
        padding: 0.4rem 0.8rem;
        font-size: 0.85rem;
    }

    /* Kompaktere Karten auf Smartphones */
    .book-card {
        margin-bottom: 0.75rem;
    }

    .book-cover {
        height: 260px; /* niedriger als Desktop */
        padding: 4px;  /* weniger Rand */
    }

    .book-info {
        padding: var(--spacing-sm);
    }

    .book-title {
        font-size: 1.1rem;
        margin-bottom: 0.25rem;
    }

    .book-author {
        margin-bottom: 0.5rem;
    }

    .book-price {
        font-size: 1.25rem;
        margin-top: 0.25rem;
    }
}

/* ==================== Simple Theme Overrides (Minimal, Flat) ==================== */
/* Diese Sektion vereinfacht das gesamte Design auf ein flaches, ruhiges Layout. */
:root {
    --color-bg: #ffffff;
    --color-bg-secondary: #ffffff;
    --color-white: #ffffff;
    --color-text: #111111;
    --color-text-light: #555555;
    --color-primary: #111111;
    --color-primary-dark: #000000;
    --color-border: #e5e7eb;
    --border-radius: 8px;
}

body {
    background: #ffffff !important;
    background-image: none !important;
    color: var(--color-text) !important;
}

/* Entfernt animiertes Grid */
body::before { display: none !important; }

.header {
    background: #ffffff !important;
    backdrop-filter: none !important;
    -webkit-backdrop-filter: none !important;
    border-bottom: 1px solid var(--color-border) !important;
    box-shadow: none !important;
}
.header::after { display: none !important; }

.logo {
    background: none !important;
    -webkit-background-clip: unset !important;
    -webkit-text-fill-color: inherit !important;
    color: #111111 !important;
}

.books-grid { gap: 1rem !important; }

.book-card {
    background: #ffffff !important;
    border: 1px solid var(--color-border) !important;
    border-radius: var(--border-radius) !important;
    box-shadow: none !important;
}
.book-card::before { display: none !important; }
.book-card:hover {
    transform: none !important;
    background: #f9fafb !important;
}

.section-title {
    background: none !important;
    -webkit-background-clip: unset !important;
    -webkit-text-fill-color: inherit !important;
    color: #111111 !important;
    text-align: left !important;
    border-bottom: 1px solid var(--color-border) !important;
    padding-bottom: 0.5rem !important;
}
.section-title::after { display: none !important; }

/* Container flach und ruhig */
.auth-container,
.book-details-container,
.success-container {
    background: #ffffff !important;
    border: 1px solid var(--color-border) !important;
    box-shadow: none !important;
}
.auth-container::before,
.book-details-container::before,
.success-container::before { display: none !important; }

/* Buttons minimal */
.btn {
    background: #ffffff !important;
    color: #111111 !important;
    border: 1px solid #111111 !important;
    box-shadow: none !important;
    transition: background-color 0.15s ease, color 0.15s ease !important;
}
.btn:hover { background: #111111 !important; color: #ffffff !important; }
.btn-primary { background: #111111 !important; color: #ffffff !important; }
.btn-primary:hover { background: #000000 !important; }

/* Inputs klar und ohne Glühen */
.form-group input {
    background: #ffffff !important;
    border: 1px solid #d1d5db !important;
    box-shadow: none !important;
}
.form-group input:focus {
    border-color: #111111 !important;
    outline: 2px solid #111111 !important;
    outline-offset: 2px !important;
    box-shadow: none !important;
}

/* Detailseite ohne Effekte, Layout neutral halten */
.book-details-title,
.book-details-price { background: none !important; -webkit-text-fill-color: inherit !important; }

/* ==================== E-Reader Optimierung (Monochrome Displays) ==================== */
@media (monochrome) {
    /* Basis-Styling für E-Reader: Schwarz/Weiß, keine Animationen */
    :root {
        --color-bg: #ffffff;
        --color-white: #ffffff;
        --color-text: #000000;
        --color-text-light: #333333;
        --color-primary: #000000;
        --color-primary-dark: #000000;
        --color-border: #000000;
    }
    
    /* Hintergrund: Weiß, keine Effekte */
    body {
        background: #ffffff !important;
        background-image: none !important;
        color: #000000;
        font-size: 1.1rem;
        line-height: 1.8;
    }
    
    /* Animiertes Grid entfernen */
    body::before {
        display: none !important;
    }
    
    /* Alle Animationen und Transitions deaktivieren */
    * {
        animation: none !important;
        transition: none !important;
    }
    
    /* Header: Einfach, schwarz/weiß */
    .header {
        background: #ffffff !important;
        backdrop-filter: none !important;
        border-bottom: 2px solid #000000;
        box-shadow: none !important;
    }
    
    .header::after {
        display: none;
    }
    
    .logo {
        background: none !important;
        -webkit-background-clip: unset !important;
        -webkit-text-fill-color: #000000 !important;
        color: #000000 !important;
        font-size: 1.5rem;
        font-weight: 700;
    }
    
    .logo::after {
        display: none;
    }
    
    /* Bücher-Grid in Liste umwandeln */
    .books-grid {
        display: block !important;
        grid-template-columns: none !important;
        gap: 0 !important;
    }
    
    /* Book Cards: Einfache Liste ohne Bilder */
    .book-card {
        display: block !important;
        background: #ffffff !important;
        backdrop-filter: none !important;
        border: 1px solid #000000 !important;
        border-radius: 0 !important;
        box-shadow: none !important;
        margin-bottom: 1rem;
        padding: 1.5rem;
        text-decoration: none;
        color: #000000 !important;
        page-break-inside: avoid; /* Für Druck/PDF */
    }
    
    .book-card::before {
        display: none !important;
    }
    
    .book-card:hover {
        transform: none !important;
        box-shadow: none !important;
        background: #f5f5f5 !important;
    }
    
    /* Bilder komplett ausblenden - auch auf Buchdetailseite */
    .book-cover,
    .book-details-cover,
    img {
        display: none !important;
    }
    
    /* Book Info: Größere Schrift, besser lesbar */
    .book-info {
        padding: 0 !important;
        display: flex;
        flex-direction: column;
        gap: 0.5rem;
    }
    
    .book-title {
        font-size: 1.4rem !important;
        font-weight: 700 !important;
        color: #000000 !important;
        margin-bottom: 0.5rem;
    }
    
    .book-author {
        font-size: 1.1rem !important;
        color: #333333 !important;
        margin-bottom: 0.5rem;
    }
    
    .book-price {
        font-size: 1.3rem !important;
        font-weight: 700 !important;
        background: none !important;
        -webkit-background-clip: unset !important;
        -webkit-text-fill-color: #000000 !important;
        color: #000000 !important;
        margin-top: 0.5rem;
    }
    
    /* Section Title */
    .section-title {
        background: none !important;
        -webkit-background-clip: unset !important;
        -webkit-text-fill-color: #000000 !important;
        color: #000000 !important;
        font-size: 2rem;
        font-weight: 700;
        margin-bottom: 2rem;
        text-align: left;
        border-bottom: 2px solid #000000;
        padding-bottom: 1rem;
    }
    
    .section-title::after {
        display: none;
    }
    
    /* Buttons: Einfach, schwarz/weiß */
    .btn {
        background: #ffffff !important;
        border: 2px solid #000000 !important;
        color: #000000 !important;
        font-size: 1.1rem;
        padding: 0.75rem 1.5rem;
        box-shadow: none !important;
    }
    
    .btn::before {
        display: none !important;
    }
    
    .btn:hover {
        background: #000000 !important;
        color: #ffffff !important;
        transform: none !important;
        box-shadow: none !important;
    }
    
    .btn-primary {
        background: #000000 !important;
        color: #ffffff !important;
    }
    
    .btn-primary:hover {
        background: #333333 !important;
        color: #ffffff !important;
    }
    
    /* Container: Einfach, keine Effekte */
    .auth-container,
    .book-details-container,
    .success-container {
        background: #ffffff !important;
        backdrop-filter: none !important;
        border: 2px solid #000000 !important;
        box-shadow: none !important;
        padding: 2rem;
    }
    
    .auth-container::before,
    .book-details-container::before,
    .success-container::before {
        display: none !important;
    }
    
    /* Book Details: Einfach, ohne Cover - Layout ändern */
    .book-details-container {
        display: block !important;
        grid-template-columns: none !important;
        gap: 0 !important;
    }
    
    .book-details-info {
        display: flex;
        flex-direction: column;
        gap: 1rem;
    }
    
    .book-details-title {
        background: none !important;
        -webkit-background-clip: unset !important;
        -webkit-text-fill-color: #000000 !important;
        color: #000000 !important;
        font-size: 2rem;
        font-weight: 700;
        margin-bottom: 0.5rem;
    }
    
    .book-details-author {
        font-size: 1.3rem !important;
        color: #333333 !important;
    }
    
    .book-details-price {
        font-size: 1.5rem !important;
        font-weight: 700 !important;
        color: #000000 !important;
    }
    
    .book-details-meta {
        font-size: 1rem;
        color: #333333;
    }
    
    .book-details-description {
        font-size: 1.1rem;
        line-height: 1.8;
        color: #000000;
        margin-top: 1rem;
    }

/* ==================== Purchased List ==================== */
.purchased-list {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.purchase-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    background: #ffffff;
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    padding: 0.75rem 1rem;
}

.purchase-title {
    font-weight: 600;
    color: var(--color-text);
}

.purchase-author {
    color: var(--color-text-light);
    font-size: 0.9rem;
}

/* Gekauft-Tabelle */
.purchased-table {
    width: 100%;
    border-collapse: collapse;
    background: #ffffff;
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    overflow: hidden;
}

.purchased-table th,
.purchased-table td {
    text-align: left;
    padding: 0.75rem 1rem;
    border-bottom: 1px solid var(--color-border);
}

.purchased-table thead th {
    background: #f9fafb;
    color: var(--color-text);
    border-bottom: 1px solid var(--color-border);
}

.purchased-table tbody tr:hover {
    background: #f9fafb;
}

/* Mehr Abstand zwischen Spalten */
.purchased-table th:not(:first-child),
.purchased-table td:not(:first-child) {
    padding-left: 2rem;
}

/* Schlichter Textlink (z. B. Home) */
.plain-link {
    color: var(--color-text);
    text-decoration: underline;
}
    
    /* Form Inputs */
    .form-group input {
        background: #ffffff !important;
        backdrop-filter: none !important;
        border: 2px solid #000000 !important;
        color: #000000 !important;
        font-size: 1.1rem;
        padding: 0.75rem;
    }
    
    .form-group input:focus {
        box-shadow: none !important;
        border-color: #000000 !important;
        outline: 2px solid #000000;
        outline-offset: 2px;
    }
    
    /* Login Prompt */
    .login-prompt {
        background: #ffffff !important;
        border: 2px solid #000000 !important;
        backdrop-filter: none !important;
    }
    
    /* Error Messages */
    .error {
        background: #ffffff !important;
        border: 2px solid #000000 !important;
        color: #000000 !important;
        backdrop-filter: none !important;
    }
}