/* ============================================
   AI Investar - Main Stylesheet
   风格：明亮、白色、米白、黑色字体、橙色高亮
   ============================================ */

/* CSS Variables */
:root {
  /* Colors */
  --color-primary: #FF6B35;
  --color-primary-dark: #E55A2B;
  --color-primary-light: #FF8A5C;
  --color-secondary: #2D3748;
  --color-accent: #7C3AED;
  
  /* Neutrals - 明亮白色/米白系列 */
  --color-white: #FFFFFF;
  --color-cream: #FBFAF9;
  --color-light: #F7F5F3;
  --color-gray-100: #F3F1EF;
  --color-gray-200: #E8E4E0;
  --color-gray-300: #D1CCC6;
  --color-gray-400: #A8A29E;
  --color-gray-500: #78716C;
  --color-gray-600: #57534E;
  --color-gray-700: #44403C;
  --color-gray-800: #292524;
  --color-gray-900: #1C1917;
  
  /* Text */
  --color-text: var(--color-gray-900);
  --color-text-secondary: var(--color-gray-600);
  --color-text-muted: var(--color-gray-500);
  
  /* Backgrounds */
  --bg-body: var(--color-cream);
  --bg-card: var(--color-white);
  --bg-hover: var(--color-light);
  
  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
  --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.1), 0 2px 4px -1px rgba(0,0,0,0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.1), 0 4px 6px -2px rgba(0,0,0,0.05);
  --shadow-xl: 0 20px 25px -5px rgba(0,0,0,0.1), 0 10px 10px -5px rgba(0,0,0,0.04);
  
  /* Typography */
  --font-sans: 'Inter', 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'Monaco', 'Consolas', 'Liberation Mono', monospace;
  
  /* Spacing */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;
  --spacing-3xl: 4rem;
  
  /* Border Radius */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-2xl: 1.5rem;
  --radius-full: 9999px;
  
  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-normal: 250ms ease;
  --transition-slow: 350ms ease;
  
  /* Layout */
  --container-max: 1280px;
  --header-height: 64px;
  --sidebar-width: 320px;
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--bg-body);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.3;
  color: var(--color-text);
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }
h5 { font-size: 1.125rem; }
h6 { font-size: 1rem; }

p { margin-bottom: var(--spacing-md); }

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

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

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

/* Container */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}

/* ============================================
   Header
   ============================================ */
.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--color-white);
  border-bottom: 1px solid var(--color-gray-200);
  backdrop-filter: blur(8px);
  background: rgba(255, 255, 255, 0.95);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--header-height);
  gap: var(--spacing-xl);
}

/* Logo */
.logo {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  font-weight: 700;
  font-size: 1.25rem;
  color: var(--color-text);
}

.logo-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  background: var(--color-primary);
  color: var(--color-white);
  border-radius: var(--radius-md);
  font-size: 0.875rem;
  font-weight: 700;
}

.logo-text {
  color: var(--color-text);
}

/* Nav Menu */
.nav-menu {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  list-style: none;
}

.nav-link {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  padding: var(--spacing-sm) var(--spacing-md);
  color: var(--color-text-secondary);
  font-weight: 500;
  font-size: 0.9375rem;
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.nav-link:hover,
.nav-link.active {
  color: var(--color-text);
  background: var(--color-light);
}

.nav-link.active {
  color: var(--color-primary);
}

/* Dropdown */
.nav-dropdown {
  position: relative;
}

.dropdown-menu {
  position: absolute;
  top: 100%;
  left: 0;
  min-width: 200px;
  padding: var(--spacing-sm);
  background: var(--color-white);
  border: 1px solid var(--color-gray-200);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  opacity: 0;
  visibility: hidden;
  transform: translateY(8px);
  transition: all var(--transition-fast);
  list-style: none;
  z-index: 50;
}

.nav-dropdown:hover .dropdown-menu,
.user-menu:hover .dropdown-menu {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.dropdown-menu li a {
  display: block;
  padding: var(--spacing-sm) var(--spacing-md);
  color: var(--color-text-secondary);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.dropdown-menu li a:hover {
  color: var(--color-text);
  background: var(--color-light);
}

/* Nav Actions */
.nav-actions {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
}

/* Search Form */
.search-form {
  position: relative;
  display: flex;
  align-items: center;
}

.search-input {
  width: 200px;
  padding: var(--spacing-sm) var(--spacing-md);
  padding-right: 40px;
  border: 1px solid var(--color-gray-200);
  border-radius: var(--radius-full);
  font-size: 0.875rem;
  background: var(--color-light);
  transition: all var(--transition-fast);
}

.search-input:focus {
  outline: none;
  width: 260px;
  border-color: var(--color-primary);
  background: var(--color-white);
  box-shadow: 0 0 0 3px rgba(255, 107, 53, 0.1);
}

.search-btn {
  position: absolute;
  right: 4px;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border: none;
  background: transparent;
  color: var(--color-text-muted);
  cursor: pointer;
  border-radius: var(--radius-full);
  transition: all var(--transition-fast);
}

.search-btn:hover {
  color: var(--color-primary);
  background: var(--color-gray-100);
}

/* User Menu */
.user-menu {
  position: relative;
}

.user-btn {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-xs);
  border: none;
  background: transparent;
  cursor: pointer;
  border-radius: var(--radius-full);
  transition: all var(--transition-fast);
}

.user-btn:hover {
  background: var(--color-light);
}

.user-avatar {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-full);
  object-fit: cover;
}

.user-dropdown {
  right: 0;
  left: auto;
}

/* Mobile Menu Button */
.mobile-menu-btn {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 40px;
  height: 40px;
  border: none;
  background: transparent;
  cursor: pointer;
  padding: 8px;
}

.mobile-menu-btn span {
  display: block;
  width: 100%;
  height: 2px;
  background: var(--color-text);
  border-radius: 2px;
  transition: all var(--transition-fast);
}

/* ============================================
   Buttons
   ============================================ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-sm) var(--spacing-lg);
  font-family: var(--font-sans);
  font-size: 0.9375rem;
  font-weight: 600;
  line-height: 1.5;
  text-align: center;
  white-space: nowrap;
  border: 2px solid transparent;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-fast);
}

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

.btn-primary:hover {
  background: var(--color-primary-dark);
  border-color: var(--color-primary-dark);
  color: var(--color-white);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.btn-outline {
  color: var(--color-text);
  background: transparent;
  border-color: var(--color-gray-300);
}

.btn-outline:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.btn-lg {
  padding: var(--spacing-md) var(--spacing-xl);
  font-size: 1rem;
}

.btn-block {
  width: 100%;
}

/* ============================================
   Hero Section
   ============================================ */
.hero {
  padding: var(--spacing-3xl) 0;
  background: linear-gradient(to bottom, var(--color-white), var(--color-cream));
}

.hero-content {
  text-align: center;
  max-width: 700px;
  margin: 0 auto var(--spacing-2xl);
}

.hero-title {
  font-size: 3rem;
  font-weight: 800;
  margin-bottom: var(--spacing-md);
}

.hero-title .highlight {
  color: var(--color-primary);
  position: relative;
}

.hero-title .highlight::after {
  content: '';
  position: absolute;
  bottom: 4px;
  left: 0;
  width: 100%;
  height: 8px;
  background: rgba(255, 107, 53, 0.2);
  z-index: -1;
  border-radius: 4px;
}

.hero-desc {
  font-size: 1.25rem;
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-xl);
}

.hero-actions {
  display: flex;
  justify-content: center;
  gap: var(--spacing-md);
  flex-wrap: wrap;
}

/* Featured Slider */
.hero-featured {
  max-width: 900px;
  margin: 0 auto;
}

.featured-slider {
  position: relative;
  overflow: hidden;
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-xl);
}

.featured-item {
  display: none;
}

.featured-item.active {
  display: block;
  animation: fadeIn 0.5s ease;
}

@keyframes fadeIn {
  from { opacity: 0; transform: scale(0.98); }
  to { opacity: 1; transform: scale(1); }
}

.featured-card {
  display: grid;
  grid-template-columns: 1fr 1fr;
  background: var(--color-white);
}

.featured-image {
  position: relative;
  overflow: hidden;
}

.featured-image img {
  width: 100%;
  height: 300px;
  object-fit: cover;
}

.featured-content {
  padding: var(--spacing-xl);
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.featured-content h2 {
  font-size: 1.5rem;
  margin-bottom: var(--spacing-md);
}

.featured-content h2 a {
  color: var(--color-text);
  transition: color var(--transition-fast);
}

.featured-content h2 a:hover {
  color: var(--color-primary);
}

.featured-dots {
  display: flex;
  justify-content: center;
  gap: var(--spacing-sm);
  margin-top: var(--spacing-md);
}

.dot {
  width: 10px;
  height: 10px;
  border: none;
  border-radius: var(--radius-full);
  background: var(--color-gray-300);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.dot:hover,
.dot.active {
  background: var(--color-primary);
  width: 30px;
}

/* ============================================
   Main Content & Grid
   ============================================ */
.main {
  min-height: calc(100vh - var(--header-height) - 200px);
}

.section {
  padding: var(--spacing-3xl) 0;
}

.section-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--spacing-xl);
  padding-bottom: var(--spacing-md);
  border-bottom: 1px solid var(--color-gray-200);
}

.section-title {
  font-size: 1.5rem;
  font-weight: 700;
}

.section-filters {
  display: flex;
  gap: var(--spacing-sm);
}

.filter-btn {
  padding: var(--spacing-sm) var(--spacing-md);
  border: none;
  background: transparent;
  color: var(--color-text-secondary);
  font-weight: 500;
  cursor: pointer;
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.filter-btn:hover,
.filter-btn.active {
  color: var(--color-primary);
  background: rgba(255, 107, 53, 0.1);
}

/* Content Grid */
.content-grid {
  display: grid;
  grid-template-columns: 1fr var(--sidebar-width);
  gap: var(--spacing-2xl);
}

/* ============================================
   Article Cards
   ============================================ */
.articles-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--spacing-lg);
}

.article-card {
  background: var(--color-white);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-normal);
}

.article-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.article-link {
  display: block;
}

.article-image {
  position: relative;
  overflow: hidden;
  aspect-ratio: 16/9;
}

.article-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform var(--transition-slow);
}

.article-card:hover .article-image img {
  transform: scale(1.05);
}

.article-image-placeholder {
  background: var(--color-light);
  display: flex;
  align-items: center;
  justify-content: center;
}

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

.article-meta {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-sm);
  font-size: 0.8125rem;
}

.article-category {
  color: var(--color-primary);
  font-weight: 600;
}

.article-date {
  color: var(--color-text-muted);
}

.article-title {
  font-size: 1.125rem;
  font-weight: 600;
  line-height: 1.4;
  margin-bottom: var(--spacing-sm);
  color: var(--color-text);
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.article-excerpt {
  font-size: 0.875rem;
  color: var(--color-text-secondary);
  line-height: 1.6;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
  margin-bottom: var(--spacing-sm);
}

.article-footer {
  display: flex;
  gap: var(--spacing-md);
  font-size: 0.8125rem;
  color: var(--color-text-muted);
}

.article-views,
.article-comments {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
}

/* ============================================
   Sidebar
   ============================================ */
.sidebar {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-xl);
}

.sidebar-widget {
  background: var(--color-white);
  padding: var(--spacing-lg);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
}

.widget-title {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: var(--spacing-md);
  padding-bottom: var(--spacing-sm);
  border-bottom: 2px solid var(--color-primary);
  display: inline-block;
}

/* Category List */
.category-list {
  list-style: none;
}

.category-list li a {
  display: flex;
  justify-content: space-between;
  padding: var(--spacing-sm) 0;
  color: var(--color-text-secondary);
  border-bottom: 1px solid var(--color-gray-100);
  transition: all var(--transition-fast);
}

.category-list li a:hover {
  color: var(--color-primary);
  padding-left: var(--spacing-sm);
}

.category-count {
  background: var(--color-light);
  padding: 2px 8px;
  border-radius: var(--radius-full);
  font-size: 0.75rem;
  color: var(--color-text-muted);
}

/* Tag Cloud */
.tag-cloud {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
}

.tag {
  display: inline-block;
  padding: var(--spacing-xs) var(--spacing-md);
  background: rgba(255, 107, 53, 0.1);
  color: var(--color-primary);
  font-size: 0.8125rem;
  font-weight: 500;
  border-radius: var(--radius-full);
  border: 1px solid transparent;
  transition: all var(--transition-fast);
}

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

/* Popular List */
.popular-list {
  list-style: none;
}

.popular-item {
  display: flex;
  gap: var(--spacing-md);
  padding: var(--spacing-md) 0;
  border-bottom: 1px solid var(--color-gray-100);
}

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

.popular-rank {
  display: flex-shrink: 0;
  align-items: flex-start;
}

.popular-rank {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  background: var(--color-gray-200);
  color: var(--color-text-muted);
  font-size: 0.8125rem;
  font-weight: 700;
  border-radius: var(--radius-md);
}

.popular-rank.top {
  background: var(--color-primary);
  color: var(--color-white);
}

.popular-item h4 {
  font-size: 0.9375rem;
  font-weight: 600;
  line-height: 1.4;
  color: var(--color-text);
  margin-bottom: var(--spacing-xs);
  transition: color var(--transition-fast);
}

.popular-item a:hover h4 {
  color: var(--color-primary);
}

.popular-views {
  font-size: 0.75rem;
  color: var(--color-text-muted);
}

/* Newsletter Widget */
.newsletter-widget {
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
  color: var(--color-white);
}

.newsletter-widget .widget-title {
  color: var(--color-white);
  border-bottom-color: rgba(255,255,255,0.3);
}

.newsletter-widget p {
  color: rgba(255,255,255,0.9);
  font-size: 0.875rem;
  margin-bottom: var(--spacing-md);
}

.newsletter-widget .newsletter-form input {
  width: 100%;
  padding: var(--spacing-sm) var(--spacing-md);
  border: none;
  border-radius: var(--radius-md);
  margin-bottom: var(--spacing-sm);
  font-size: 0.875rem;
}

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

.newsletter-widget .btn:hover {
  background: var(--color-cream);
}

/* ============================================
   Pagination
   ============================================ */
.pagination {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: var(--spacing-md);
  margin-top: var(--spacing-2xl);
  padding-top: var(--spacing-xl);
  border-top: 1px solid var(--color-gray-200);
}

.pagination-btn {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  padding: var(--spacing-sm) var(--spacing-lg);
  background: var(--color-white);
  border: 1px solid var(--color-gray-200);
  border-radius: var(--radius-md);
  color: var(--color-text-secondary);
  font-weight: 500;
  transition: all var(--transition-fast);
}

.pagination-btn:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.pagination-numbers {
  display: flex;
  gap: var(--spacing-sm);
}

.pagination-num {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-md);
  color: var(--color-text-secondary);
  font-weight: 500;
  transition: all var(--transition-fast);
}

.pagination-num:hover,
.pagination-num.active {
  background: var(--color-primary);
  color: var(--color-white);
}

/* ============================================
   Article Single
   ============================================ */
.article-single {
  max-width: 800px;
  margin: 0 auto;
}

.article-header {
  margin-bottom: var(--spacing-xl);
}

.article-header .category {
  display: inline-block;
  padding: var(--spacing-xs) var(--spacing-md);
  background: rgba(255, 107, 53, 0.1);
  color: var(--color-primary);
  font-size: 0.875rem;
  font-weight: 600;
  border-radius: var(--radius-full);
  margin-bottom: var(--spacing-md);
}

.article-header h1 {
  font-size: 2.25rem;
  line-height: 1.3;
  margin-bottom: var(--spacing-md);
}

.article-meta-full {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--spacing-lg);
  color: var(--color-text-secondary);
  font-size: 0.875rem;
}

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

.author-info img {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-full);
}

.author-info .name {
  font-weight: 600;
  color: var(--color-text);
}

.article-featured-image {
  border-radius: var(--radius-lg);
  overflow: hidden;
  margin-bottom: var(--spacing-xl);
}

.article-featured-image img {
  width: 100%;
}

/* Article Content */
.article-body {
  font-size: 1.0625rem;
  line-height: 1.8;
}

.article-body h2 {
  font-size: 1.5rem;
  margin-top: var(--spacing-2xl);
  margin-bottom: var(--spacing-md);
}

.article-body h3 {
  font-size: 1.25rem;
  margin-top: var(--spacing-xl);
  margin-bottom: var(--spacing-md);
}

.article-body p {
  margin-bottom: var(--spacing-md);
}

.article-body ul, .article-body ol {
  margin-bottom: var(--spacing-md);
  padding-left: var(--spacing-xl);
}

.article-body li {
  margin-bottom: var(--spacing-sm);
}

.article-body blockquote {
  margin: var(--spacing-xl) 0;
  padding: var(--spacing-lg);
  background: var(--color-light);
  border-left: 4px solid var(--color-primary);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
}

.article-body code {
  background: var(--color-light);
  padding: 2px 6px;
  border-radius: var(--radius-sm);
  font-family: var(--font-mono);
  font-size: 0.9em;
}

.article-body pre {
  background: var(--color-gray-900);
  color: var(--color-gray-100);
  padding: var(--spacing-lg);
  border-radius: var(--radius-md);
  overflow-x: auto;
  margin-bottom: var(--spacing-md);
}

.article-body pre code {
  background: none;
  padding: 0;
}

.article-body img {
  border-radius: var(--radius-md);
  margin: var(--spacing-lg) auto;
}

/* Video Container */
.video-container {
  position: relative;
  padding-bottom: 56.25%;
  height: 0;
  overflow: hidden;
  border-radius: var(--radius-md);
  margin: var(--spacing-lg) 0;
}

.video-container iframe,
.video-container video {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
}

/* Article Tags */
.article-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
  margin-top: var(--spacing-2xl);
  padding-top: var(--spacing-xl);
  border-top: 1px solid var(--color-gray-200);
}

/* Article Actions */
.article-actions {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--spacing-xl) 0;
  border-top: 1px solid var(--color-gray-200);
  border-bottom: 1px solid var(--color-gray-200);
  margin-top: var(--spacing-xl);
}

.share-buttons {
  display: flex;
  gap: var(--spacing-sm);
}

.share-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-full);
  background: var(--color-light);
  color: var(--color-text-secondary);
  transition: all var(--transition-fast);
}

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

/* Related Articles */
.related-articles {
  margin-top: var(--spacing-3xl);
}

.related-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--spacing-lg);
}

/* ============================================
   Comments
   ============================================ */
.comments-section {
  margin-top: var(--spacing-3xl);
}

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

.comment-item {
  display: flex;
  gap: var(--spacing-md);
  padding: var(--spacing-lg);
  background: var(--color-white);
  border-radius: var(--radius-lg);
}

.comment-avatar {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-full);
  flex-shrink: 0;
}

.comment-content {
  flex: 1;
}

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

.comment-author {
  font-weight: 600;
}

.comment-date {
  font-size: 0.8125rem;
  color: var(--color-text-muted);
}

.comment-text {
  font-size: 0.9375rem;
  line-height: 1.6;
}

.comment-actions {
  display: flex;
  gap: var(--spacing-md);
  margin-top: var(--spacing-sm);
  font-size: 0.8125rem;
}

.comment-actions a {
  color: var(--color-text-muted);
}

.comment-actions a:hover {
  color: var(--color-primary);
}

.comment-reply {
  margin-left: var(--spacing-2xl);
  margin-top: var(--spacing-md);
}

/* Comment Form */
.comment-form {
  background: var(--color-white);
  padding: var(--spacing-xl);
  border-radius: var(--radius-lg);
  margin-bottom: var(--spacing-xl);
}

.comment-form textarea {
  width: 100%;
  min-height: 120px;
  padding: var(--spacing-md);
  border: 1px solid var(--color-gray-200);
  border-radius: var(--radius-md);
  resize: vertical;
  font-family: var(--font-sans);
  font-size: 0.9375rem;
  transition: border-color var(--transition-fast);
}

.comment-form textarea:focus {
  outline: none;
  border-color: var(--color-primary);
}

/* ============================================
   Auth Pages
   ============================================ */
.auth-page {
  min-height: calc(100vh - var(--header-height));
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--spacing-2xl);
}

.auth-container {
  width: 100%;
  max-width: 400px;
}

.auth-card {
  background: var(--color-white);
  padding: var(--spacing-2xl);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-lg);
}

.auth-header {
  text-align: center;
  margin-bottom: var(--spacing-xl);
}

.auth-header h1 {
  font-size: 1.5rem;
  margin-bottom: var(--spacing-sm);
}

.auth-header p {
  color: var(--color-text-secondary);
}

.form-group {
  margin-bottom: var(--spacing-md);
}

.form-label {
  display: block;
  margin-bottom: var(--spacing-xs);
  font-weight: 500;
  font-size: 0.875rem;
}

.form-input {
  width: 100%;
  padding: var(--spacing-sm) var(--spacing-md);
  border: 1px solid var(--color-gray-200);
  border-radius: var(--radius-md);
  font-size: 0.9375rem;
  transition: all var(--transition-fast);
}

.form-input:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(255, 107, 53, 0.1);
}

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

.auth-footer {
  text-align: center;
  margin-top: var(--spacing-lg);
  padding-top: var(--spacing-lg);
  border-top: 1px solid var(--color-gray-200);
  font-size: 0.875rem;
  color: var(--color-text-secondary);
}

/* ============================================
   Footer
   ============================================ */
.footer {
  background: var(--color-white);
  border-top: 1px solid var(--color-gray-200);
  padding: var(--spacing-3xl) 0 var(--spacing-xl);
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1.5fr;
  gap: var(--spacing-2xl);
  margin-bottom: var(--spacing-2xl);
}

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

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

.social-links {
  display: flex;
  gap: var(--spacing-sm);
}

.social-links a {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: var(--radius-full);
  background: var(--color-light);
  color: var(--color-text-secondary);
  transition: all var(--transition-fast);
}

.social-links a:hover {
  background: var(--color-primary);
  color: var(--color-white);
}

.footer-links h4 {
  font-size: 0.9375rem;
  font-weight: 700;
  margin-bottom: var(--spacing-md);
}

.footer-links ul {
  list-style: none;
}

.footer-links li {
  margin-bottom: var(--spacing-sm);
}

.footer-links a {
  color: var(--color-text-secondary);
  font-size: 0.875rem;
  transition: color var(--transition-fast);
}

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

.footer-newsletter h4 {
  font-size: 0.9375rem;
  font-weight: 700;
  margin-bottom: var(--spacing-sm);
}

.footer-newsletter p {
  font-size: 0.875rem;
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-md);
}

.newsletter-form {
  display: flex;
  gap: var(--spacing-sm);
}

.newsletter-form input {
  flex: 1;
  padding: var(--spacing-sm) var(--spacing-md);
  border: 1px solid var(--color-gray-200);
  border-radius: var(--radius-md);
  font-size: 0.875rem;
}

.newsletter-form input:focus {
  outline: none;
  border-color: var(--color-primary);
}

.footer-bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: var(--spacing-lg);
  border-top: 1px solid var(--color-gray-200);
  font-size: 0.8125rem;
  color: var(--color-text-muted);
}

/* ============================================
   Back to Top
   ============================================ */
.back-to-top {
  position: fixed;
  bottom: var(--spacing-xl);
  right: var(--spacing-xl);
  width: 48px;
  height: 48px;
  border: none;
  border-radius: var(--radius-full);
  background: var(--color-primary);
  color: var(--color-white);
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transform: translateY(20px);
  transition: all var(--transition-normal);
  z-index: 50;
  box-shadow: var(--shadow-lg);
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-to-top:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-xl);
}

/* ============================================
   Empty State
   ============================================ */
.empty-state {
  text-align: center;
  padding: var(--spacing-3xl);
  color: var(--color-text-muted);
}

.empty-state svg {
  margin-bottom: var(--spacing-lg);
  opacity: 0.5;
}

/* ============================================
   Responsive
   ============================================ */
@media (max-width: 1024px) {
  .content-grid {
    grid-template-columns: 1fr;
  }
  
  .sidebar {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-lg);
  }
  
  .footer-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .nav-menu,
  .nav-actions {
    display: none;
  }
  
  .mobile-menu-btn {
    display: flex;
  }
  
  .nav-menu.active {
    display: flex !important;
    flex-direction: column;
    position: absolute;
    top: 70px;
    left: 0;
    right: 0;
    background: #fff;
    padding: 20px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
    z-index: 1000;
  }
  
  .nav-menu.active .nav-item {
    margin: 0;
    padding: 12px 0;
    border-bottom: 1px solid #eee;
  }
  
  .hero-title {
    font-size: 2rem;
  }
  
  .hero-desc {
    font-size: 1rem;
  }
  
  .featured-card {
    grid-template-columns: 1fr;
  }
  
  .featured-image img {
    height: 200px;
  }
  
  .articles-grid {
    grid-template-columns: 1fr;
  }
  
  .sidebar {
    grid-template-columns: 1fr;
  }
  
  .footer-grid {
    grid-template-columns: 1fr;
    gap: var(--spacing-xl);
  }
  
  .footer-bottom {
    flex-direction: column;
    gap: var(--spacing-sm);
    text-align: center;
  }
  
  .article-header h1 {
    font-size: 1.75rem;
  }
  
  .article-meta-full {
    font-size: 0.8125rem;
  }
}

/* ============================================
   Animations
   ============================================ */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (max-width: 640px) {
  .articles-grid {
    grid-template-columns: 1fr;
  }
  
  .sidebar {
    grid-template-columns: 1fr;
  }
  
  .footer-grid {
    grid-template-columns: 1fr;
    gap: var(--spacing-xl);
  }
  
  .footer-bottom {
    flex-direction: column;
    gap: var(--spacing-sm);
    text-align: center;
  }
  
  .pagination {
    flex-wrap: wrap;
  }
}

/* ============================================
   Empty State
   ============================================ */
.empty-state {
  text-align: center;
  padding: var(--spacing-3xl);
  color: var(--color-text-muted);
}

.empty-state svg {
  margin-bottom: var(--spacing-md);
  opacity: 0.5;
}

/* ============================================
   Utilities
   ============================================ */
.text-center { text-align: center; }
.text-muted { color: var(--color-text-muted); }
.mt-1 { margin-top: var(--spacing-sm); }
.mt-2 { margin-top: var(--spacing-md); }
.mt-3 { margin-top: var(--spacing-lg); }
.mb-1 { margin-bottom: var(--spacing-sm); }
.mb-2 { margin-bottom: var(--spacing-md); }
.mb-3 { margin-bottom: var(--spacing-lg); }

/* Responsive */
@media (max-width: 1024px) {
  .content-grid {
    grid-template-columns: 1fr;
  }
  
  .sidebar {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  :root {
    --header-height: 56px;
  }
  
  h1 { font-size: 2rem; }
  h2 { font-size: 1.5rem; }
  
  .hero-title {
    font-size: 2rem;
  }
  
  .hero-desc {
    font-size: 1rem;
  }
  
  .nav-menu,
  .nav-actions {
    display: none;
  }
  
  .mobile-menu-btn {
    display: flex;
  }
  
  .featured-card {
    grid-template-columns: 1fr;
  }
  
  .featured-image img {
    height: 200px;
  }
  
  .article-header h1 {
    font-size: 1.75rem;
  }
}

/* Print Styles */
@media print {
  .header,
  .footer,
  .sidebar,
  .back-to-top,
  .comment-form {
    display: none;
  }
  
  .main {
    max-width: none;
  }
  
  .article-body {
    font-size: 12pt;
  }
}