/* ============================================
   知识实验室 - 文学实验室美学
   设计理念：现代主义印刷 × 数字实验性
   ============================================ */

/* CSS 变量定义 */
:root {
    /* 颜色系统 */
    --color-primary: #0a0a0a;
    --color-secondary: #1a1a1a;
    --color-accent: #d4af37;
    --color-text: #2a2a2a;
    --color-text-light: #666666;
    --color-bg: #fafafa;
    --color-white: #ffffff;
    --color-border: #e0e0e0;

    /* 字体系统 */
    --font-display: 'Playfair Display', serif;
    --font-heading: 'Crimson Pro', serif;
    --font-body: 'DM Sans', sans-serif;

    /* 间距系统 */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 2rem;
    --spacing-lg: 4rem;
    --spacing-xl: 6rem;

    /* 动画时长 */
    --duration-fast: 0.2s;
    --duration-normal: 0.4s;
    --duration-slow: 0.8s;
}

/* ============================================
   基础样式重置
   ============================================ */

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

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-body);
    background-color: var(--color-bg);
    color: var(--color-text);
    line-height: 1.6;
    overflow-x: hidden;
    position: relative;
}

/* ============================================
   背景装饰系统
   ============================================ */

.bg-decoration {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 0;
    overflow: hidden;
}

.floating-text {
    position: absolute;
    font-family: var(--font-display);
    font-size: 20rem;
    font-weight: 900;
    color: var(--color-primary);
    opacity: 0.02;
    user-select: none;
    animation: float 20s ease-in-out infinite;
}

.floating-text.large {
    font-size: 25rem;
    opacity: 0.03;
}

.floating-currency {
    position: absolute;
    font-size: 8rem;
    color: var(--color-accent);
    opacity: 0.05;
    animation: float 15s ease-in-out infinite;
}

@keyframes float {
    0%, 100% {
        transform: translateY(0) rotate(0deg);
    }
    50% {
        transform: translateY(-30px) rotate(5deg);
    }
}

/* 纸张纹理叠加 */
.grain-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 1;
    opacity: 0.03;
    background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 400 400' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='noiseFilter'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' /%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23noiseFilter)' /%3E%3C/svg%3E");
}

/* ============================================
   容器与布局
   ============================================ */

.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: var(--spacing-md);
    position: relative;
    z-index: 2;
}

/* ============================================
   头部样式
   ============================================ */

.site-header {
    padding: var(--spacing-xl) 0 var(--spacing-lg);
    position: relative;
}

.header-content {
    max-width: 800px;
}

.logo-section {
    margin-bottom: var(--spacing-md);
}

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

.title-main {
    font-family: var(--font-display);
    font-size: 4.5rem;
    font-weight: 900;
    color: var(--color-primary);
    letter-spacing: -0.02em;
    line-height: 1;
    animation: fadeInUp 0.8s ease-out;
}

.title-sub {
    font-family: var(--font-body);
    font-size: 0.875rem;
    font-weight: 500;
    letter-spacing: 0.3em;
    color: var(--color-text-light);
    text-transform: uppercase;
    animation: fadeInUp 0.8s ease-out 0.1s backwards;
}

.header-line {
    width: 120px;
    height: 3px;
    background: linear-gradient(90deg, var(--color-primary) 0%, transparent 100%);
    margin-top: var(--spacing-sm);
    animation: expandWidth 1s ease-out 0.3s backwards;
}

.site-tagline {
    font-family: var(--font-heading);
    font-size: 1.25rem;
    color: var(--color-text);
    font-weight: 400;
    animation: fadeInUp 0.8s ease-out 0.2s backwards;
}

/* 装饰性引用 */
.decorative-quote {
    position: absolute;
    right: 0;
    top: 50%;
    transform: translateY(-50%);
    max-width: 300px;
    opacity: 0.6;
    animation: fadeIn 1s ease-out 0.5s backwards;
}

.quote-mark {
    font-family: var(--font-display);
    font-size: 8rem;
    line-height: 0.5;
    color: var(--color-accent);
    opacity: 0.3;
}

.decorative-quote p {
    font-family: var(--font-heading);
    font-size: 1.125rem;
    font-style: italic;
    color: var(--color-text-light);
    margin-top: var(--spacing-sm);
}

/* ============================================
   主要内容区域
   ============================================ */

.main-content {
    padding: var(--spacing-lg) 0;
}

.section-header {
    margin-bottom: var(--spacing-lg);
    position: relative;
}

.section-title {
    display: flex;
    align-items: baseline;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-sm);
}

.title-number {
    font-family: var(--font-body);
    font-size: 0.875rem;
    font-weight: 700;
    color: var(--color-accent);
    letter-spacing: 0.1em;
}

.title-text {
    font-family: var(--font-display);
    font-size: 3rem;
    font-weight: 700;
    color: var(--color-primary);
    letter-spacing: -0.01em;
}

.section-line {
    width: 100%;
    height: 1px;
    background: linear-gradient(90deg, var(--color-primary) 0%, transparent 50%);
}

/* ============================================
   书籍网格
   ============================================ */

.books-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(500px, 1fr));
    gap: var(--spacing-lg);
}

/* ============================================
   书籍卡片
   ============================================ */

.book-card {
    background: var(--color-white);
    border: 2px solid var(--color-primary);
    position: relative;
    transition: transform var(--duration-normal) ease;
    animation: fadeInUp 0.6s ease-out backwards;
}

.book-card:hover {
    transform: translateY(-8px);
}

.book-card:hover .cover-overlay {
    opacity: 0.1;
}

.book-card-inner {
    display: grid;
    grid-template-columns: 200px 1fr;
    gap: var(--spacing-md);
    padding: var(--spacing-md);
}

/* 书籍封面 */
.book-cover {
    position: relative;
    aspect-ratio: 3/4;
    background: var(--color-primary);
    overflow: hidden;
}

.cover-typography {
    position: relative;
    z-index: 2;
    height: 100%;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    padding: var(--spacing-md);
    color: var(--color-white);
}

.cover-title {
    font-family: var(--font-display);
    font-size: 2rem;
    font-weight: 900;
    line-height: 1;
    letter-spacing: -0.02em;
}

.cover-pattern {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    font-size: 1.5rem;
    opacity: 0.3;
    color: var(--color-accent);
}

.cover-author {
    font-family: var(--font-body);
    font-size: 0.875rem;
    font-weight: 500;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    opacity: 0.8;
}

.cover-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, transparent 0%, var(--color-accent) 100%);
    opacity: 0.2;
    transition: opacity var(--duration-normal) ease;
    z-index: 1;
}

/* 书籍信息 */
.book-info {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) 0;
}

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

.book-category,
.book-format {
    font-size: 0.75rem;
    font-weight: 700;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--color-text-light);
}

.book-title {
    font-family: var(--font-display);
    font-size: 2rem;
    font-weight: 700;
    color: var(--color-primary);
    line-height: 1.2;
    margin: var(--spacing-xs) 0;
}

.book-author {
    font-size: 1rem;
    color: var(--color-text-light);
    font-weight: 500;
}

.book-description {
    font-size: 0.9375rem;
    line-height: 1.7;
    color: var(--color-text);
    margin: var(--spacing-sm) 0;
}

.book-actions {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    margin-top: auto;
}

/* 按钮样式 */
.btn-primary {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: 0.875rem 2rem;
    background: var(--color-primary);
    color: var(--color-white);
    text-decoration: none;
    font-weight: 600;
    font-size: 0.9375rem;
    letter-spacing: 0.02em;
    transition: all var(--duration-normal) ease;
    position: relative;
    overflow: hidden;
}

.btn-primary::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: var(--color-accent);
    transition: left var(--duration-normal) ease;
    z-index: 0;
}

.btn-primary:hover::before {
    left: 0;
}

.btn-primary .btn-text,
.btn-primary .btn-arrow {
    position: relative;
    z-index: 1;
}

.btn-arrow {
    font-size: 1.25rem;
    transition: transform var(--duration-normal) ease;
}

.btn-primary:hover .btn-arrow {
    transform: translateX(4px);
}

.book-stats {
    display: flex;
    gap: var(--spacing-sm);
}

.stat-item {
    display: flex;
    align-items: center;
    gap: 0.25rem;
    font-size: 0.875rem;
    color: var(--color-text-light);
}

.stat-icon {
    font-size: 1rem;
}

/* 卡片装饰 */
.card-decoration {
    position: absolute;
    top: 0;
    right: 0;
    width: 60px;
    height: 60px;
    pointer-events: none;
}

.decoration-line {
    position: absolute;
    top: var(--spacing-sm);
    right: var(--spacing-sm);
    width: 30px;
    height: 2px;
    background: var(--color-accent);
}

.decoration-corner {
    position: absolute;
    top: var(--spacing-sm);
    right: var(--spacing-sm);
    width: 2px;
    height: 30px;
    background: var(--color-accent);
}

/* 占位卡片 */
.book-card-placeholder {
    border-style: dashed;
    border-color: var(--color-border);
    background: transparent;
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 400px;
    opacity: 0.6;
    transition: all var(--duration-normal) ease;
}

.book-card-placeholder:hover {
    opacity: 1;
    border-color: var(--color-primary);
}

.placeholder-content {
    text-align: center;
    padding: var(--spacing-lg);
}

.placeholder-icon {
    font-size: 4rem;
    color: var(--color-text-light);
    margin-bottom: var(--spacing-sm);
}

.placeholder-text {
    font-family: var(--font-heading);
    font-size: 1.125rem;
    color: var(--color-text-light);
    line-height: 1.6;
}

/* ============================================
   详情页样式
   ============================================ */

.detail-page {
    background: var(--color-white);
}

.detail-nav {
    padding: var(--spacing-md) 0;
    margin-bottom: var(--spacing-md);
    position: relative;
}

.back-link {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    text-decoration: none;
    color: var(--color-text);
    font-weight: 500;
    font-size: 0.9375rem;
    transition: all var(--duration-normal) ease;
}

.back-arrow {
    font-size: 1.25rem;
    transition: transform var(--duration-normal) ease;
}

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

.back-link:hover .back-arrow {
    transform: translateX(-4px);
}

.nav-line {
    width: 100%;
    height: 1px;
    background: var(--color-border);
    margin-top: var(--spacing-sm);
}

/* 书籍详情布局 */
.book-detail {
    display: grid;
    grid-template-columns: 450px 1fr;
    gap: var(--spacing-xl);
    padding: var(--spacing-lg) 0;
}

/* 详情页封面区域 */
.detail-cover-section {
    position: sticky;
    top: var(--spacing-md);
    height: fit-content;
}

.detail-cover {
    aspect-ratio: 3/4;
    background: var(--color-primary);
    position: relative;
    overflow: hidden;
    margin-bottom: var(--spacing-md);
    animation: fadeIn 0.8s ease-out;
}

.cover-typography.large {
    padding: var(--spacing-lg);
}

.cover-title-large {
    font-family: var(--font-display);
    font-size: 3.5rem;
    font-weight: 900;
    line-height: 0.9;
    letter-spacing: -0.02em;
    color: var(--color-white);
    margin-bottom: var(--spacing-md);
}

.cover-title-large .highlight {
    color: var(--color-accent);
}

.cover-pattern-large {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    margin: var(--spacing-lg) 0;
    opacity: 0.2;
}

.pattern-row {
    display: flex;
    gap: 1rem;
    font-size: 2rem;
    color: var(--color-accent);
}

.cover-author-large {
    font-family: var(--font-body);
    font-size: 1rem;
    font-weight: 500;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    color: var(--color-white);
    opacity: 0.8;
    position: absolute;
    bottom: var(--spacing-lg);
    left: var(--spacing-lg);
}

/* 详情页引用 */
.detail-quote {
    padding: var(--spacing-md);
    border-left: 3px solid var(--color-accent);
    background: var(--color-bg);
    animation: fadeInUp 0.8s ease-out 0.2s backwards;
}

.quote-mark-large {
    font-family: var(--font-display);
    font-size: 4rem;
    line-height: 0.5;
    color: var(--color-accent);
    opacity: 0.3;
}

.quote-text {
    font-family: var(--font-heading);
    font-size: 1.125rem;
    font-style: italic;
    color: var(--color-text);
    line-height: 1.6;
    margin-top: var(--spacing-sm);
}

/* 详情页内容区域 */
.detail-content-section {
    animation: fadeInUp 0.8s ease-out 0.1s backwards;
}

.detail-header {
    margin-bottom: var(--spacing-lg);
    padding-bottom: var(--spacing-md);
    position: relative;
}

.detail-meta {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-sm);
    font-size: 0.875rem;
    font-weight: 600;
    letter-spacing: 0.05em;
    text-transform: uppercase;
    color: var(--color-text-light);
}

.meta-separator {
    color: var(--color-border);
}

.detail-title {
    font-family: var(--font-display);
    font-size: 4rem;
    font-weight: 900;
    color: var(--color-primary);
    line-height: 1.1;
    letter-spacing: -0.02em;
    margin: var(--spacing-sm) 0;
}

.detail-author {
    display: flex;
    align-items: baseline;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-md);
}

.author-label {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--color-text-light);
    letter-spacing: 0.1em;
    text-transform: uppercase;
}

.author-name {
    font-family: var(--font-heading);
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--color-primary);
}

.title-decoration {
    width: 80px;
    height: 4px;
    background: var(--color-accent);
    margin-top: var(--spacing-md);
}

/* 详情信息区域 */
.detail-info {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-xl);
}

.info-section {
    border-left: 2px solid var(--color-border);
    padding-left: var(--spacing-md);
    transition: border-color var(--duration-normal) ease;
}

.info-section:hover {
    border-color: var(--color-accent);
}

.info-title {
    display: flex;
    align-items: baseline;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-md);
}

.info-number {
    font-family: var(--font-body);
    font-size: 0.875rem;
    font-weight: 700;
    color: var(--color-accent);
    letter-spacing: 0.1em;
}

.info-text {
    font-family: var(--font-heading);
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--color-primary);
}

.info-content {
    font-size: 1.0625rem;
    line-height: 1.8;
    color: var(--color-text);
}

.info-content p {
    margin-bottom: var(--spacing-sm);
}

.info-content p:last-child {
    margin-bottom: 0;
}

/* 核心观点列表 */
.key-points {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.key-points li {
    display: flex;
    align-items: flex-start;
    gap: var(--spacing-sm);
}

.point-marker {
    font-size: 1.25rem;
    color: var(--color-accent);
    flex-shrink: 0;
}

.point-text {
    flex: 1;
}

/* 读者标签 */
.reader-tags {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
}

.tag {
    padding: 0.5rem 1rem;
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--color-text);
    transition: all var(--duration-normal) ease;
}

.tag:hover {
    background: var(--color-primary);
    color: var(--color-white);
    border-color: var(--color-primary);
}

/* 下载区域 */
.download-area {
    margin-top: var(--spacing-xl);
}

.download-box {
    background: var(--color-primary);
    color: var(--color-white);
    padding: var(--spacing-lg);
    position: relative;
    overflow: hidden;
}

.download-box::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, var(--color-accent) 0%, transparent 70%);
    opacity: 0.1;
    animation: pulse 4s ease-in-out infinite;
}

@keyframes pulse {
    0%, 100% {
        transform: scale(1);
        opacity: 0.1;
    }
    50% {
        transform: scale(1.1);
        opacity: 0.15;
    }
}

.download-header {
    margin-bottom: var(--spacing-md);
    position: relative;
    z-index: 1;
}

.download-title {
    font-family: var(--font-display);
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: var(--spacing-xs);
}

.download-subtitle {
    font-size: 1rem;
    opacity: 0.8;
}

.btn-download-main {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: 1.25rem 3rem;
    background: var(--color-accent);
    color: var(--color-primary);
    text-decoration: none;
    font-weight: 700;
    font-size: 1.125rem;
    letter-spacing: 0.02em;
    transition: all var(--duration-normal) ease;
    position: relative;
    z-index: 1;
    margin-bottom: var(--spacing-md);
}

.btn-download-main:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 24px rgba(212, 175, 55, 0.3);
}

.btn-icon {
    font-size: 1.5rem;
}

.download-info {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding-top: var(--spacing-md);
    border-top: 1px solid rgba(255, 255, 255, 0.2);
    position: relative;
    z-index: 1;
}

.info-item {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.info-label {
    font-size: 0.75rem;
    opacity: 0.6;
    text-transform: uppercase;
    letter-spacing: 0.1em;
}

.info-value {
    font-size: 0.9375rem;
    font-weight: 600;
}

.info-divider {
    width: 1px;
    height: 30px;
    background: rgba(255, 255, 255, 0.2);
}

/* ============================================
   页脚
   ============================================ */

.site-footer {
    padding: var(--spacing-xl) 0 var(--spacing-md);
    margin-top: var(--spacing-xl);
}

.footer-content {
    text-align: center;
}

.footer-line {
    width: 100%;
    height: 1px;
    background: linear-gradient(90deg, transparent 0%, var(--color-border) 50%, transparent 100%);
    margin-bottom: var(--spacing-md);
}

.footer-text {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    font-size: 0.875rem;
    color: var(--color-text-light);
}

.footer-year {
    font-weight: 700;
}

.footer-separator {
    opacity: 0.3;
}

.footer-name {
    font-family: var(--font-heading);
    font-weight: 600;
}

.footer-tagline {
    font-style: italic;
}

/* ============================================
   动画定义
   ============================================ */

@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes expandWidth {
    from {
        width: 0;
    }
    to {
        width: 120px;
    }
}

/* ============================================
   响应式设计
   ============================================ */

@media (max-width: 1200px) {
    .books-grid {
        grid-template-columns: 1fr;
    }

    .book-detail {
        grid-template-columns: 1fr;
        gap: var(--spacing-lg);
    }

    .detail-cover-section {
        position: relative;
        top: 0;
    }

    .decorative-quote {
        position: relative;
        right: auto;
        top: auto;
        transform: none;
        margin-top: var(--spacing-md);
    }
}

@media (max-width: 768px) {
    :root {
        --spacing-lg: 3rem;
        --spacing-xl: 4rem;
    }

    .title-main {
        font-size: 3rem;
    }

    .title-text {
        font-size: 2rem;
    }

    .book-card-inner {
        grid-template-columns: 1fr;
    }

    .book-cover {
        aspect-ratio: 16/9;
    }

    .detail-title {
        font-size: 2.5rem;
    }

    .floating-text {
        font-size: 10rem;
    }

    .floating-text.large {
        font-size: 12rem;
    }
}

@media (max-width: 480px) {
    .container {
        padding: var(--spacing-sm);
    }

    .title-main {
        font-size: 2.5rem;
    }

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

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