/* ========================================
   我的学习笔记 - 组件样式
   ======================================== */

/* ========== 导航栏 ========== */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  background: linear-gradient(135deg, var(--color-bg-dark) 0%, #3d2a20 100%);
  box-shadow: var(--shadow-medium);
  z-index: 1000;
  transition: all var(--transition-normal);
}

.navbar.scrolled {
  height: 60px;
  background: rgba(44, 24, 16, 0.98);
  backdrop-filter: blur(10px);
}

.navbar-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  max-width: var(--container-xl);
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}

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

.navbar-logo {
  font-family: var(--font-heading);
  font-size: var(--text-xl);
  font-weight: 700;
  color: var(--color-text-light);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.navbar-logo::before {
  content: '📚';
  font-size: 1.5rem;
}

.navbar-logo:hover {
  color: var(--color-accent-gold);
}

.navbar-menu {
  display: flex;
  align-items: center;
  gap: var(--spacing-xl);
  list-style: none;
  margin: 0;
  padding: 0;
}

.navbar-menu a {
  color: var(--color-text-light);
  font-size: var(--text-sm);
  font-weight: 500;
  padding: var(--spacing-sm) var(--spacing-md);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
  position: relative;
}

.navbar-menu a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  width: 0;
  height: 2px;
  background: var(--color-accent-gold);
  transition: all var(--transition-fast);
  transform: translateX(-50%);
}

.navbar-menu a:hover::after,
.navbar-menu a.active::after {
  width: 80%;
}

.navbar-menu a:hover {
  color: var(--color-accent-gold);
}

/* 移动端菜单按钮 */
.navbar-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--spacing-sm);
}

.navbar-toggle span {
  display: block;
  width: 25px;
  height: 2px;
  background: var(--color-text-light);
  transition: all var(--transition-fast);
}

@media (max-width: 768px) {
  .navbar-toggle {
    display: flex;
  }
  
  .navbar-menu {
    position: fixed;
    top: var(--nav-height);
    left: 0;
    right: 0;
    background: var(--color-bg-dark);
    flex-direction: column;
    padding: var(--spacing-lg);
    gap: var(--spacing-md);
    transform: translateY(-100%);
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-normal);
  }
  
  .navbar-menu.active {
    transform: translateY(0);
    opacity: 1;
    visibility: visible;
  }
}

/* ========== 按钮 ========== */
.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-body);
  font-size: var(--text-sm);
  font-weight: 500;
  text-decoration: none;
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.btn-primary {
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
  color: var(--color-text-light);
  box-shadow: var(--shadow-soft);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-medium);
  color: var(--color-text-light);
}

.btn-secondary {
  background: transparent;
  color: var(--color-primary);
  border: 2px solid var(--color-primary);
}

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

.btn-gold {
  background: linear-gradient(135deg, var(--color-accent-gold) 0%, #B8860B 100%);
  color: var(--color-text-primary);
}

.btn-gold:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 15px rgba(218, 165, 32, 0.4);
}

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

.btn-sm {
  padding: var(--spacing-xs) var(--spacing-md);
  font-size: var(--text-xs);
}

/* ========== 卡片 ========== */
.card {
  background: var(--color-bg-card);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-soft);
  overflow: hidden;
  transition: all var(--transition-normal);
}

.card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-card-hover);
}

.card-image {
  width: 100%;
  height: 200px;
  object-fit: cover;
  transition: transform var(--transition-slow);
}

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

.card-image-wrapper {
  overflow: hidden;
  position: relative;
}

.card-category {
  position: absolute;
  top: var(--spacing-md);
  left: var(--spacing-md);
  padding: var(--spacing-xs) var(--spacing-md);
  background: rgba(44, 24, 16, 0.8);
  color: var(--color-text-light);
  font-size: var(--text-xs);
  font-weight: 500;
  border-radius: var(--radius-full);
  backdrop-filter: blur(5px);
}

.card-body {
  padding: var(--spacing-lg);
}

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

.card-title a {
  color: inherit;
}

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

.card-excerpt {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-md);
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.card-meta {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  font-size: var(--text-xs);
  color: var(--color-text-muted);
}

.card-meta-item {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
}

/* 文章卡片网格 */
.articles-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: var(--spacing-xl);
}

@media (max-width: 768px) {
  .articles-grid {
    grid-template-columns: 1fr;
  }
}

/* 特色文章卡片 */
.card-featured {
  grid-column: span 2;
  display: grid;
  grid-template-columns: 1fr 1fr;
}

.card-featured .card-image {
  height: 100%;
  min-height: 300px;
}

.card-featured .card-body {
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: var(--spacing-2xl);
}

.card-featured .card-title {
  font-size: var(--text-2xl);
}

.card-featured .card-excerpt {
  -webkit-line-clamp: 4;
}

@media (max-width: 992px) {
  .card-featured {
    grid-column: span 1;
    grid-template-columns: 1fr;
  }
  
  .card-featured .card-image {
    min-height: 200px;
  }
}

/* ========== 分类标签 ========== */
.tag {
  display: inline-block;
  padding: var(--spacing-xs) var(--spacing-md);
  font-size: var(--text-xs);
  font-weight: 500;
  border-radius: var(--radius-full);
  transition: all var(--transition-fast);
}

.tag-programming {
  background: rgba(74, 144, 164, 0.15);
  color: var(--color-cat-programming);
}

.tag-learning {
  background: rgba(123, 104, 238, 0.15);
  color: var(--color-cat-learning);
}

.tag-math {
  background: rgba(205, 133, 63, 0.15);
  color: var(--color-cat-math);
}

.tag-humanities {
  background: rgba(188, 143, 143, 0.15);
  color: var(--color-cat-humanities);
}

.tag-lifestyle {
  background: rgba(107, 142, 35, 0.15);
  color: var(--color-cat-lifestyle);
}

/* ========== Hero区域 ========== */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: calc(var(--nav-height) + var(--spacing-3xl)) var(--spacing-lg) var(--spacing-3xl);
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: 
    radial-gradient(ellipse at 30% 20%, rgba(218, 165, 32, 0.1) 0%, transparent 50%),
    radial-gradient(ellipse at 70% 80%, rgba(139, 69, 19, 0.1) 0%, transparent 50%);
  pointer-events: none;
}

.hero-content {
  max-width: 800px;
  position: relative;
  z-index: 1;
}

.hero-badge {
  display: inline-block;
  padding: var(--spacing-sm) var(--spacing-lg);
  background: rgba(139, 69, 19, 0.1);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-full);
  font-size: var(--text-sm);
  color: var(--color-primary);
  margin-bottom: var(--spacing-lg);
  animation: fadeInUp 0.6s ease forwards;
}

.hero-title {
  font-family: var(--font-heading);
  font-size: clamp(2.5rem, 8vw, 4.5rem);
  font-weight: 700;
  color: var(--color-text-primary);
  margin-bottom: var(--spacing-lg);
  line-height: 1.2;
  animation: fadeInUp 0.6s ease 0.1s forwards;
  opacity: 0;
}

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

.hero-title span::after {
  content: '';
  position: absolute;
  bottom: 5px;
  left: 0;
  width: 100%;
  height: 8px;
  background: var(--color-accent-gold);
  opacity: 0.3;
  z-index: -1;
}

.hero-description {
  font-size: var(--text-lg);
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-2xl);
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
  animation: fadeInUp 0.6s ease 0.2s forwards;
  opacity: 0;
}

.hero-buttons {
  display: flex;
  gap: var(--spacing-md);
  justify-content: center;
  flex-wrap: wrap;
  animation: fadeInUp 0.6s ease 0.3s forwards;
  opacity: 0;
}

.hero-stats {
  display: flex;
  justify-content: center;
  gap: var(--spacing-3xl);
  margin-top: var(--spacing-3xl);
  animation: fadeInUp 0.6s ease 0.4s forwards;
  opacity: 0;
}

.hero-stat {
  text-align: center;
}

.hero-stat-number {
  font-family: var(--font-heading);
  font-size: var(--text-4xl);
  font-weight: 700;
  color: var(--color-primary);
}

.hero-stat-label {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
}

/* 装饰元素 */
.hero-decoration {
  position: absolute;
  pointer-events: none;
  opacity: 0.1;
}

.hero-decoration-1 {
  top: 15%;
  left: 10%;
  font-size: 8rem;
  animation: float 6s ease-in-out infinite;
}

.hero-decoration-2 {
  bottom: 20%;
  right: 10%;
  font-size: 6rem;
  animation: float 8s ease-in-out infinite reverse;
}

/* ========== 页脚 ========== */
.footer {
  background: var(--color-bg-dark);
  color: var(--color-text-light);
  padding: var(--spacing-3xl) 0 var(--spacing-xl);
  margin-top: var(--spacing-3xl);
}

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

.footer-brand {
  font-family: var(--font-heading);
  font-size: var(--text-xl);
  font-weight: 700;
  margin-bottom: var(--spacing-md);
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.footer-brand::before {
  content: '📚';
}

.footer-description {
  color: var(--color-text-muted);
  font-size: var(--text-sm);
  line-height: 1.8;
}

.footer-title {
  font-size: var(--text-base);
  font-weight: 600;
  margin-bottom: var(--spacing-lg);
  color: var(--color-accent-gold);
}

.footer-links {
  list-style: none;
  padding: 0;
  margin: 0;
}

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

.footer-links a {
  color: var(--color-text-muted);
  font-size: var(--text-sm);
  transition: color var(--transition-fast);
}

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

.footer-bottom {
  padding-top: var(--spacing-xl);
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  text-align: center;
  font-size: var(--text-sm);
  color: var(--color-text-muted);
}

@media (max-width: 768px) {
  .footer-content {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 480px) {
  .footer-content {
    grid-template-columns: 1fr;
  }
}

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

@keyframes float {
  0%, 100% {
    transform: translateY(0) rotate(0deg);
  }
  50% {
    transform: translateY(-20px) rotate(5deg);
  }
}

@keyframes pulse {
  0%, 100% {
    opacity: 1;
  }
  50% {
    opacity: 0.5;
  }
}

/* 滚动显示动画 */
.fade-in {
  opacity: 0;
  transform: translateY(30px);
  transition: all 0.6s ease;
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ========== 阅读进度条 ========== */
.reading-progress {
  position: fixed;
  top: 0;
  left: 0;
  width: 0%;
  height: 3px;
  background: linear-gradient(90deg, var(--color-primary), var(--color-accent-gold));
  z-index: 1001;
  transition: width 0.1s ease;
}

/* ========== 返回顶部按钮 ========== */
.back-to-top {
  position: fixed;
  bottom: 30px;
  right: 30px;
  width: 50px;
  height: 50px;
  background: var(--color-primary);
  color: var(--color-text-light);
  border: none;
  border-radius: var(--radius-full);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--text-xl);
  box-shadow: var(--shadow-medium);
  opacity: 0;
  visibility: hidden;
  transform: translateY(20px);
  transition: all var(--transition-normal);
  z-index: 999;
}

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

.back-to-top:hover {
  background: var(--color-primary-dark);
  transform: translateY(-3px);
}

/* ========== 分类筛选 ========== */
.filter-tabs {
  display: flex;
  gap: var(--spacing-sm);
  flex-wrap: wrap;
  justify-content: center;
  margin-bottom: var(--spacing-2xl);
}

.filter-tab {
  padding: var(--spacing-sm) var(--spacing-lg);
  background: transparent;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-full);
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.filter-tab:hover,
.filter-tab.active {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: var(--color-text-light);
}

/* ========== 章节标题 ========== */
.section {
  padding: var(--spacing-3xl) 0;
}

.section-header {
  text-align: center;
  margin-bottom: var(--spacing-2xl);
}

.section-badge {
  display: inline-block;
  padding: var(--spacing-xs) var(--spacing-md);
  background: rgba(139, 69, 19, 0.1);
  border-radius: var(--radius-full);
  font-size: var(--text-xs);
  color: var(--color-primary);
  margin-bottom: var(--spacing-md);
  text-transform: uppercase;
  letter-spacing: 1px;
}

.section-title {
  font-family: var(--font-heading);
  font-size: var(--text-3xl);
  margin-bottom: var(--spacing-md);
}

.section-description {
  color: var(--color-text-secondary);
  max-width: 600px;
  margin: 0 auto;
}