/* ============================================
   皮革工艺 - 白皮书简报风格样式表
   主色调: #673ab7 (深紫色)
   域名: www.pigeqianbao.cn
   ============================================ */

/* CSS 变量定义 */
:root {
  --accent-color: #673ab7;
  --accent-dark: #512da8;
  --accent-light: #9575cd;
  --text-primary: #212121;
  --text-secondary: #757575;
  --text-muted: #9e9e9e;
  --bg-primary: #ffffff;
  --bg-secondary: #fafafa;
  --bg-tertiary: #f5f5f5;
  --border-color: #e0e0e0;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.08);
  --shadow-md: 0 2px 8px rgba(0,0,0,0.1);
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --max-width: 1200px;
  --content-width: 800px;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: "SF Mono", Monaco, "Cascadia Code", "Roboto Mono", Consolas, monospace;
}

/* 重置样式 */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

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

body {
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.7;
  color: var(--text-primary);
  background-color: var(--bg-primary);
}

a {
  color: var(--accent-color);
  text-decoration: none;
  transition: color 0.2s ease;
}

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

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

ul, ol {
  list-style: none;
}

/* ============================================
   布局容器
   ============================================ */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

.content-wrapper {
  max-width: var(--content-width);
  margin: 0 auto;
}

/* ============================================
   页头 Header
   ============================================ */
.header {
  background-color: var(--bg-primary);
  border-bottom: 1px solid var(--border-color);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
}

.logo-icon {
  width: 36px;
  height: 36px;
  background: var(--accent-color);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: 1rem;
}

.nav {
  display: flex;
  align-items: center;
  gap: 2rem;
}

.nav-link {
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--text-secondary);
  padding: 0.5rem 0;
  border-bottom: 2px solid transparent;
}

.nav-link:hover,
.nav-link.active {
  color: var(--accent-color);
  border-bottom-color: var(--accent-color);
}

.search-box {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  background: var(--bg-tertiary);
  border-radius: var(--radius-md);
  padding: 0.5rem 1rem;
  min-width: 240px;
}

.search-box input {
  border: none;
  background: transparent;
  font-size: 0.875rem;
  outline: none;
  width: 100%;
  color: var(--text-primary);
}

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

.search-btn {
  background: none;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  font-size: 1rem;
}

/* ============================================
   Hero 区域
   ============================================ */
.hero {
  background: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-tertiary) 100%);
  padding: 4rem 0;
  text-align: center;
}

.hero-title {
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 1rem;
  letter-spacing: -0.02em;
}

.hero-subtitle {
  font-size: 1.125rem;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto 2rem;
}

.hero-search {
  max-width: 560px;
  margin: 0 auto;
}

.hero-search .search-box {
  background: var(--bg-primary);
  border: 2px solid var(--border-color);
  padding: 0.875rem 1.25rem;
  box-shadow: var(--shadow-sm);
}

.hero-search .search-box:focus-within {
  border-color: var(--accent-color);
}

/* ============================================
   分类导航
   ============================================ */
.categories {
  padding: 2rem 0;
  border-bottom: 1px solid var(--border-color);
}

.category-list {
  display: flex;
  justify-content: center;
  gap: 1rem;
  flex-wrap: wrap;
}

.category-item {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  background: var(--bg-secondary);
  border-radius: var(--radius-md);
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--text-secondary);
  transition: all 0.2s ease;
}

.category-item:hover {
  background: var(--accent-color);
  color: white;
}

.category-item .icon {
  font-size: 1.125rem;
}

/* ============================================
   主要内容区
   ============================================ */
.main {
  padding: 3rem 0;
}

.section-title {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 1.5rem;
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.section-title::before {
  content: '';
  width: 4px;
  height: 24px;
  background: var(--accent-color);
  border-radius: 2px;
}

/* ============================================
   白皮书卡片
   ============================================ */
.whitepaper-list {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.whitepaper-card {
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  transition: box-shadow 0.2s ease;
}

.whitepaper-card:hover {
  box-shadow: var(--shadow-md);
}

.whitepaper-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 1.5rem;
  margin-bottom: 1rem;
}

.whitepaper-title {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--text-primary);
  line-height: 1.4;
}

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

.whitepaper-meta {
  display: flex;
  align-items: center;
  gap: 1rem;
  font-size: 0.875rem;
  color: var(--text-muted);
  flex-shrink: 0;
}

.whitepaper-meta span {
  display: flex;
  align-items: center;
  gap: 0.375rem;
}

.whitepaper-summary {
  font-size: 0.9375rem;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 1.25rem;
}

.whitepaper-tags {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.tag {
  padding: 0.375rem 0.875rem;
  background: var(--bg-tertiary);
  border-radius: var(--radius-sm);
  font-size: 0.8125rem;
  color: var(--text-secondary);
}

.tag.accent {
  background: var(--accent-light);
  color: white;
}

.whitepaper-actions {
  display: flex;
  gap: 1rem;
  margin-top: 1.25rem;
  padding-top: 1.25rem;
  border-top: 1px solid var(--border-color);
}

/* ============================================
   按钮样式
   ============================================ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.625rem 1.25rem;
  font-size: 0.875rem;
  font-weight: 500;
  border-radius: var(--radius-md);
  border: none;
  cursor: pointer;
  transition: all 0.2s ease;
}

.btn-primary {
  background: var(--accent-color);
  color: white;
}

.btn-primary:hover {
  background: var(--accent-dark);
  color: white;
}

.btn-secondary {
  background: var(--bg-tertiary);
  color: var(--text-secondary);
  border: 1px solid var(--border-color);
}

.btn-secondary:hover {
  background: var(--bg-secondary);
  color: var(--text-primary);
}

.btn-outline {
  background: transparent;
  color: var(--accent-color);
  border: 1px solid var(--accent-color);
}

.btn-outline:hover {
  background: var(--accent-color);
  color: white;
}

/* ============================================
   侧边栏组件
   ============================================ */
.sidebar-section {
  background: var(--bg-secondary);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  margin-bottom: 1.5rem;
}

.sidebar-title {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 1rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--border-color);
}

.article-list {
  display: flex;
  flex-direction: column;
  gap: 0.875rem;
}

.article-item {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  padding: 0.5rem 0;
  border-bottom: 1px solid var(--border-color);
}

.article-item:last-child {
  border-bottom: none;
}

.article-num {
  width: 24px;
  height: 24px;
  background: var(--accent-color);
  color: white;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.75rem;
  font-weight: 600;
  flex-shrink: 0;
}

.article-num.gray {
  background: var(--text-muted);
}

.article-link {
  font-size: 0.9375rem;
  color: var(--text-primary);
  line-height: 1.5;
}

.article-link:hover {
  color: var(--accent-color);
}

.article-meta {
  font-size: 0.8125rem;
  color: var(--text-muted);
  margin-top: 0.25rem;
}

/* ============================================
   面包屑导航
   ============================================ */
.breadcrumb {
  padding: 1.25rem 0;
  border-bottom: 1px solid var(--border-color);
}

.breadcrumb-list {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.875rem;
  color: var(--text-muted);
}

.breadcrumb-list a {
  color: var(--text-secondary);
}

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

.breadcrumb-separator {
  color: var(--text-muted);
}

.breadcrumb-current {
  color: var(--text-primary);
  font-weight: 500;
}

/* ============================================
   页面标题区
   ============================================ */
.page-header {
  padding: 2.5rem 0;
  text-align: center;
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
}

.page-title {
  font-size: 2rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.75rem;
}

.page-desc {
  font-size: 1rem;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto;
}

/* ============================================
   排序工具栏
   ============================================ */
.sort-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 0;
  margin-bottom: 1.5rem;
  border-bottom: 1px solid var(--border-color);
}

.sort-options {
  display: flex;
  gap: 1.5rem;
  font-size: 0.875rem;
}

.sort-option {
  color: var(--text-secondary);
  cursor: pointer;
  padding: 0.25rem 0;
  border-bottom: 2px solid transparent;
}

.sort-option:hover,
.sort-option.active {
  color: var(--accent-color);
  border-bottom-color: var(--accent-color);
}

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

/* ============================================
   分页
   ============================================ */
.pagination {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 0.5rem;
  padding: 2.5rem 0;
}

.page-btn {
  min-width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0 0.75rem;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-secondary);
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all 0.2s ease;
}

.page-btn:hover {
  background: var(--bg-secondary);
  color: var(--text-primary);
}

.page-btn.active {
  background: var(--accent-color);
  color: white;
  border-color: var(--accent-color);
}

.page-btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

/* ============================================
   文章详情页
   ============================================ */
.article-header {
  padding: 2.5rem 0 1.5rem;
  border-bottom: 1px solid var(--border-color);
  margin-bottom: 2rem;
}

.article-title {
  font-size: 2rem;
  font-weight: 700;
  color: var(--text-primary);
  line-height: 1.3;
  margin-bottom: 1.25rem;
}

.article-meta-bar {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  flex-wrap: wrap;
  font-size: 0.875rem;
  color: var(--text-muted);
}

.article-meta-bar span {
  display: flex;
  align-items: center;
  gap: 0.375rem;
}

.article-content {
  font-size: 1rem;
  line-height: 1.9;
  color: var(--text-primary);
}

.article-content h2 {
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--text-primary);
  margin: 2.5rem 0 1rem;
  padding-bottom: 0.75rem;
  border-bottom: 2px solid var(--accent-light);
}

.article-content h3 {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--text-primary);
  margin: 2rem 0 0.875rem;
}

.article-content p {
  margin-bottom: 1.25rem;
  color: var(--text-secondary);
}

.article-content ul,
.article-content ol {
  margin-bottom: 1.25rem;
  padding-left: 1.5rem;
}

.article-content ul {
  list-style: disc;
}

.article-content ol {
  list-style: decimal;
}

.article-content li {
  margin-bottom: 0.5rem;
  color: var(--text-secondary);
}

.article-content strong {
  color: var(--text-primary);
  font-weight: 600;
}

/* 执行摘要 */
.executive-summary {
  background: var(--bg-secondary);
  border-left: 4px solid var(--accent-color);
  padding: 1.5rem;
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  margin: 1.5rem 0;
}

.executive-summary h3 {
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--accent-color);
  margin-bottom: 0.75rem;
  margin-top: 0;
}

/* 关键点 */
.key-points {
  background: var(--bg-tertiary);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  margin: 1.5rem 0;
}

.key-points h3 {
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 1rem;
  margin-top: 0;
}

.key-points ul {
  list-style: none;
  padding-left: 0;
  margin-bottom: 0;
}

.key-points li {
  position: relative;
  padding-left: 1.5rem;
  margin-bottom: 0.75rem;
}

.key-points li::before {
  content: '✓';
  position: absolute;
  left: 0;
  color: var(--accent-color);
  font-weight: 600;
}

/* 目录 */
.toc {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  margin: 1.5rem 0;
}

.toc h3 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 1rem;
  margin-top: 0;
}

.toc-list {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.toc-item {
  font-size: 0.9375rem;
  color: var(--text-secondary);
  padding: 0.375rem 0;
  border-bottom: 1px solid var(--border-color);
}

.toc-item:last-child {
  border-bottom: none;
}

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

/* 结论 */
.conclusion {
  background: linear-gradient(135deg, var(--accent-light) 0%, var(--accent-color) 100%);
  color: white;
  padding: 1.5rem;
  border-radius: var(--radius-md);
  margin: 1.5rem 0;
}

.conclusion h3 {
  font-size: 1.125rem;
  font-weight: 600;
  margin-bottom: 0.75rem;
  margin-top: 0;
}

.conclusion p {
  color: rgba(255,255,255,0.9);
  margin-bottom: 0;
}

/* 下载区 */
.download-section {
  display: flex;
  gap: 1rem;
  padding: 1.5rem;
  background: var(--bg-secondary);
  border-radius: var(--radius-md);
  margin: 1.5rem 0;
}

/* 相关推荐 */
.related-section {
  margin-top: 3rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border-color);
}

.related-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
  margin-top: 1.25rem;
}

.related-card {
  background: var(--bg-secondary);
  border-radius: var(--radius-md);
  padding: 1.25rem;
  transition: box-shadow 0.2s ease;
}

.related-card:hover {
  box-shadow: var(--shadow-sm);
}

.related-card-title {
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.5rem;
  line-height: 1.4;
}

.related-card-meta {
  font-size: 0.8125rem;
  color: var(--text-muted);
}

/* ============================================
   三栏布局
   ============================================ */
.three-column-layout {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: 1.5rem;
  margin-top: 2rem;
}

/* ============================================
   404 页面
   ============================================ */
.error-page {
  min-height: 60vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 4rem 1.5rem;
}

.error-code {
  font-size: 8rem;
  font-weight: 700;
  color: var(--accent-color);
  line-height: 1;
  margin-bottom: 1rem;
  opacity: 0.8;
}

.error-title {
  font-size: 1.75rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.75rem;
}

.error-message {
  font-size: 1rem;
  color: var(--text-secondary);
  margin-bottom: 2rem;
  max-width: 400px;
}

.error-actions {
  display: flex;
  gap: 1rem;
}

/* ============================================
   页脚
   ============================================ */
.footer {
  background: var(--bg-secondary);
  border-top: 1px solid var(--border-color);
  padding: 3rem 0 2rem;
  margin-top: 3rem;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 3rem;
  margin-bottom: 2rem;
}

.footer-brand {
  max-width: 300px;
}

.footer-logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 1rem;
}

.footer-desc {
  font-size: 0.875rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

.footer-title {
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 1rem;
}

.footer-links {
  display: flex;
  flex-direction: column;
  gap: 0.625rem;
}

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

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

.footer-bottom {
  padding-top: 2rem;
  border-top: 1px solid var(--border-color);
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.8125rem;
  color: var(--text-muted);
}

.footer-bottom a {
  color: var(--text-muted);
}

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

/* ============================================
   响应式设计
   ============================================ */
@media (max-width: 1024px) {
  .three-column-layout {
    grid-template-columns: 1fr 1fr;
  }

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

  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
  }
}

@media (max-width: 768px) {
  .header-inner {
    flex-wrap: wrap;
    height: auto;
    padding: 1rem 0;
    gap: 1rem;
  }

  .nav {
    order: 3;
    width: 100%;
    justify-content: center;
    gap: 1rem;
  }

  .search-box {
    min-width: auto;
    flex: 1;
  }

  .hero {
    padding: 2.5rem 0;
  }

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

  .hero-subtitle {
    font-size: 1rem;
  }

  .category-list {
    gap: 0.5rem;
  }

  .category-item {
    padding: 0.625rem 1rem;
    font-size: 0.875rem;
  }

  .whitepaper-header {
    flex-direction: column;
    gap: 0.75rem;
  }

  .whitepaper-title {
    font-size: 1.125rem;
  }

  .whitepaper-actions {
    flex-direction: column;
  }

  .btn {
    width: 100%;
  }

  .three-column-layout {
    grid-template-columns: 1fr;
  }

  .related-grid {
    grid-template-columns: 1fr;
  }

  .download-section {
    flex-direction: column;
  }

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

  .article-content h2 {
    font-size: 1.25rem;
  }

  .article-content h3 {
    font-size: 1.125rem;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 1.5rem;
  }

  .footer-bottom {
    flex-direction: column;
    gap: 0.75rem;
    text-align: center;
  }

  .error-code {
    font-size: 5rem;
  }

  .error-actions {
    flex-direction: column;
    width: 100%;
    padding: 0 2rem;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 1rem;
  }

  .whitepaper-card {
    padding: 1.25rem;
  }

  .sidebar-section {
    padding: 1.25rem;
  }

  .sort-bar {
    flex-direction: column;
    gap: 1rem;
    align-items: flex-start;
  }

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

/* ============================================
   辅助类
   ============================================ */
.text-center {
  text-align: center;
}

.mt-2 {
  margin-top: 2rem;
}

.mb-2 {
  margin-bottom: 2rem;
}

.hidden {
  display: none;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}