/* ========== CSS 变量 & 重置 ========== */
:root {
  --primary: #777bb3;
  --primary-dark: #5c5f99;
  --primary-light: #9ea0cc;
  --accent: #f05340;
  --accent-light: #ff6b5a;
  --bg: #f8f9fc;
  --bg-card: #ffffff;
  --text: #1e1e2e;
  --text-secondary: #6c6f85;
  --text-light: #9ca3b4;
  --border: #e8eaf0;
  --shadow: 0 1px 3px rgba(0, 0, 0, 0.06), 0 1px 2px rgba(0, 0, 0, 0.04);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 10px 30px rgba(0, 0, 0, 0.1);
  --radius: 12px;
  --radius-sm: 8px;
  --transition: 0.25s ease;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
  --navbar-height: 68px;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-sans);
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

a { text-decoration: none; color: inherit; }
ul { list-style: none; }
img { max-width: 100%; display: block; }

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ========== 导航栏 ========== */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--navbar-height);
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(16px) saturate(180%);
  -webkit-backdrop-filter: blur(16px) saturate(180%);
  border-bottom: 1px solid var(--border);
  z-index: 1000;
  transition: var(--transition);
}

.navbar.scrolled {
  box-shadow: var(--shadow);
}

.navbar-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.3rem;
  font-weight: 800;
  color: var(--primary-dark);
  transition: var(--transition);
}

.logo i { font-size: 1.6rem; color: var(--primary); }
.logo:hover { opacity: 0.85; }

.nav-links {
  display: flex;
  gap: 6px;
}

.nav-links a {
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-secondary);
  transition: var(--transition);
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--primary-dark);
  background: rgba(119, 123, 179, 0.1);
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 8px;
}

.search-toggle, .menu-toggle {
  width: 40px;
  height: 40px;
  border: none;
  border-radius: 50%;
  background: transparent;
  color: var(--text-secondary);
  font-size: 1.1rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition);
}

.search-toggle:hover, .menu-toggle:hover {
  background: var(--border);
  color: var(--text);
}

.menu-toggle { display: none; }

/* 搜索栏 */
.search-bar {
  position: absolute;
  top: var(--navbar-height);
  left: 0;
  right: 0;
  background: var(--bg-card);
  border-bottom: 1px solid var(--border);
  padding: 16px 0;
  transform: translateY(-120%);
  opacity: 0;
  transition: 0.3s ease;
  pointer-events: none;
}

.search-bar.active {
  transform: translateY(0);
  opacity: 1;
  pointer-events: auto;
}

.search-wrapper {
  display: flex;
  align-items: center;
  gap: 12px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0 16px;
  transition: var(--transition);
}

.search-wrapper:focus-within {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(119, 123, 179, 0.15);
}

.search-wrapper i { color: var(--text-light); font-size: 1rem; }

.search-wrapper input {
  flex: 1;
  border: none;
  background: transparent;
  padding: 14px 0;
  font-size: 1rem;
  font-family: var(--font-sans);
  outline: none;
  color: var(--text);
}

.search-close {
  border: none;
  background: transparent;
  color: var(--text-light);
  cursor: pointer;
  font-size: 1.2rem;
  padding: 4px;
  transition: var(--transition);
}

.search-close:hover { color: var(--text); }

/* ========== Hero ========== */
.hero {
  padding: 120px 0 60px;
  background: linear-gradient(135deg, #f0f1f8 0%, #e8e9f5 50%, #f5f0f8 100%);
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -20%;
  width: 600px;
  height: 600px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(119, 123, 179, 0.06) 0%, transparent 70%);
  pointer-events: none;
}

.hero-content {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 48px;
  align-items: center;
  position: relative;
}

.hero-badge {
  display: inline-block;
  padding: 4px 14px;
  background: rgba(119, 123, 179, 0.12);
  color: var(--primary-dark);
  border-radius: 20px;
  font-size: 0.8rem;
  font-weight: 600;
  margin-bottom: 16px;
  letter-spacing: 0.3px;
}

.hero-text h1 {
  font-size: 2.2rem;
  font-weight: 800;
  line-height: 1.3;
  margin-bottom: 16px;
  color: var(--text);
}

.hero-text p {
  font-size: 1.05rem;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 20px;
}

.hero-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
  margin-bottom: 24px;
  font-size: 0.88rem;
  color: var(--text-light);
}

.hero-meta i { margin-right: 6px; }

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 28px;
  border-radius: var(--radius-sm);
  font-size: 0.95rem;
  font-weight: 600;
  font-family: var(--font-sans);
  cursor: pointer;
  border: none;
  transition: var(--transition);
}

.btn-primary {
  background: var(--primary);
  color: #fff;
}

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

.btn-sm { padding: 8px 16px; font-size: 0.85rem; }

.hero-image {
  display: flex;
  justify-content: center;
}

.hero-img-placeholder {
  width: 100%;
  max-width: 380px;
  aspect-ratio: 4/3;
  border-radius: var(--radius);
  background: linear-gradient(135deg, var(--primary-light) 0%, var(--primary) 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 6rem;
  color: rgba(255, 255, 255, 0.3);
  box-shadow: var(--shadow-lg);
  position: relative;
  overflow: hidden;
}

.hero-img-placeholder::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, transparent 40%, rgba(255,255,255,0.1) 100%);
}

/* ========== 主内容区 ========== */
.main-content {
  padding: 48px 0 80px;
}

.content-grid {
  display: grid;
  grid-template-columns: 1fr 320px;
  gap: 40px;
}

.section-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 16px;
  margin-bottom: 28px;
}

.section-header h2 {
  font-size: 1.5rem;
  font-weight: 700;
  position: relative;
}

.section-header h2::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 36px;
  height: 3px;
  background: var(--primary);
  border-radius: 2px;
}

.filter-tabs {
  display: flex;
  gap: 4px;
  background: var(--border);
  border-radius: var(--radius-sm);
  padding: 3px;
}

.filter-btn {
  border: none;
  background: transparent;
  padding: 6px 16px;
  border-radius: 6px;
  font-size: 0.85rem;
  font-weight: 500;
  font-family: var(--font-sans);
  color: var(--text-secondary);
  cursor: pointer;
  transition: var(--transition);
}

.filter-btn.active {
  background: var(--bg-card);
  color: var(--primary-dark);
  box-shadow: var(--shadow);
}

.filter-btn:hover:not(.active) { color: var(--text); }

/* ========== 文章卡片 ========== */
.articles-list {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.article-card {
  background: var(--bg-card);
  border-radius: var(--radius);
  padding: 24px;
  border: 1px solid var(--border);
  transition: var(--transition);
  cursor: pointer;
}

.article-card:hover {
  border-color: var(--primary-light);
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.article-card-header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 12px;
  flex-wrap: wrap;
}

.article-category {
  display: inline-block;
  padding: 2px 10px;
  border-radius: 4px;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.3px;
}

.cat-tutorial { background: rgba(59, 130, 246, 0.1); color: #2563eb; }
.cat-framework { background: rgba(239, 68, 68, 0.1); color: #dc2626; }
.cat-practice { background: rgba(16, 185, 129, 0.1); color: #059669; }
.cat-opensource { background: rgba(245, 158, 11, 0.1); color: #d97706; }

.article-date {
  font-size: 0.8rem;
  color: var(--text-light);
}

.article-card h3 {
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 8px;
  line-height: 1.4;
  transition: var(--transition);
}

.article-card:hover h3 { color: var(--primary-dark); }

.article-excerpt {
  color: var(--text-secondary);
  font-size: 0.9rem;
  line-height: 1.65;
  margin-bottom: 16px;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.article-card-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
}

.article-author {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.article-author-avatar {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--primary-light), var(--primary));
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.7rem;
  font-weight: 700;
  color: #fff;
}

.article-stats {
  display: flex;
  gap: 14px;
  font-size: 0.8rem;
  color: var(--text-light);
}

.article-stats i { margin-right: 4px; }

/* ========== 分页 ========== */
.pagination {
  display: flex;
  justify-content: center;
  gap: 6px;
  margin-top: 36px;
}

.pagination button {
  width: 38px;
  height: 38px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--bg-card);
  color: var(--text-secondary);
  font-size: 0.9rem;
  font-weight: 500;
  font-family: var(--font-sans);
  cursor: pointer;
  transition: var(--transition);
}

.pagination button:hover,
.pagination button.active {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
}

/* ========== 侧边栏 ========== */
.sidebar {
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.sidebar-card {
  background: var(--bg-card);
  border-radius: var(--radius);
  padding: 24px;
  border: 1px solid var(--border);
}

.sidebar-card h3 {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 16px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.sidebar-card h3 i {
  color: var(--primary);
  font-size: 0.9rem;
}

.sidebar-card p {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

.category-list li {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 0;
  border-bottom: 1px solid var(--border);
  cursor: pointer;
  transition: var(--transition);
}

.category-list li:last-child { border-bottom: none; }

.category-list li:hover { color: var(--primary-dark); }

.category-list .count {
  background: var(--bg);
  padding: 1px 10px;
  border-radius: 12px;
  font-size: 0.78rem;
  color: var(--text-light);
  font-weight: 500;
}

.tag-cloud {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.tag {
  display: inline-block;
  padding: 4px 12px;
  border-radius: 6px;
  font-size: 0.8rem;
  font-weight: 500;
  background: var(--bg);
  color: var(--text-secondary);
  transition: var(--transition);
  cursor: pointer;
}

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

.tag-lg { font-size: 0.95rem; padding: 6px 16px; }
.tag-md { font-size: 0.85rem; }
.tag-sm { font-size: 0.75rem; }

.hot-list li {
  padding: 12px 0;
  border-bottom: 1px solid var(--border);
  display: flex;
  gap: 12px;
  cursor: pointer;
  transition: var(--transition);
}

.hot-list li:last-child { border-bottom: none; }
.hot-list li:hover { color: var(--primary-dark); }

.hot-index {
  width: 24px;
  height: 24px;
  border-radius: 6px;
  background: var(--bg);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--text-light);
  flex-shrink: 0;
}

.hot-index.top { background: var(--accent); color: #fff; }
.hot-index.top2 { background: var(--primary); color: #fff; }
.hot-index.top3 { background: var(--primary-light); color: #fff; }

.hot-list .hot-title {
  font-size: 0.88rem;
  font-weight: 500;
  line-height: 1.4;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.subscribe-form {
  display: flex;
  gap: 8px;
  margin-top: 12px;
}

.subscribe-form input {
  flex: 1;
  padding: 10px 14px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: 0.88rem;
  font-family: var(--font-sans);
  outline: none;
  background: var(--bg);
  transition: var(--transition);
}

.subscribe-form input:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(119, 123, 179, 0.12);
}

/* ========== 页脚 ========== */
.footer {
  background: #1e1e2e;
  color: #c8c9d8;
  padding: 60px 0 0;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 40px;
}

.footer-brand .logo {
  color: #fff;
  margin-bottom: 16px;
  font-size: 1.2rem;
}

.footer-brand .logo i { color: var(--primary-light); }

.footer-brand p {
  font-size: 0.9rem;
  line-height: 1.7;
  margin-bottom: 20px;
  color: #9ca3b4;
}

.social-links {
  display: flex;
  gap: 12px;
}

.social-links a {
  width: 38px;
  height: 38px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.08);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #c8c9d8;
  transition: var(--transition);
  font-size: 1rem;
}

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

.footer-links h4 {
  color: #fff;
  font-size: 0.95rem;
  font-weight: 600;
  margin-bottom: 16px;
}

.footer-links a {
  display: block;
  font-size: 0.88rem;
  padding: 5px 0;
  color: #9ca3b4;
  transition: var(--transition);
}

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

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  padding: 20px 0;
  text-align: center;
  font-size: 0.85rem;
  color: #6c6f85;
}

/* ========== 回到顶部 ========== */
.back-to-top {
  position: fixed;
  bottom: 32px;
  right: 32px;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--primary);
  color: #fff;
  border: none;
  font-size: 1.1rem;
  cursor: pointer;
  box-shadow: var(--shadow-md);
  opacity: 0;
  transform: translateY(20px);
  pointer-events: none;
  transition: var(--transition);
  z-index: 999;
}

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

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

/* ========== 空状态 ========== */
.empty-state {
  text-align: center;
  padding: 60px 20px;
  color: var(--text-light);
}

.empty-state i {
  font-size: 3rem;
  margin-bottom: 16px;
  display: block;
}

.empty-state p {
  font-size: 1rem;
}

/* ========== 响应式 ========== */
@media (max-width: 1024px) {
  .content-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 768px) {
  .hero { padding: 100px 0 40px; }

  .hero-content {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .hero-text h1 { font-size: 1.6rem; }
  .hero-image { order: -1; }
  .hero-img-placeholder { max-width: 280px; font-size: 4rem; }

  .nav-links {
    display: none;
    position: absolute;
    top: var(--navbar-height);
    left: 0;
    right: 0;
    background: var(--bg-card);
    border-bottom: 1px solid var(--border);
    flex-direction: column;
    padding: 12px 24px;
    box-shadow: var(--shadow-md);
  }

  .nav-links.open { display: flex; }

  .nav-links a {
    padding: 12px 12px;
    border-radius: 0;
    border-bottom: 1px solid var(--border);
  }

  .nav-links a:last-child { border-bottom: none; }

  .menu-toggle { display: flex; }

  .section-header {
    flex-direction: column;
    align-items: flex-start;
  }

  .filter-tabs { width: 100%; overflow-x: auto; }
  .filter-btn { flex-shrink: 0; }

  .articles-list { gap: 16px; }
  .article-card { padding: 18px; }
  .article-card h3 { font-size: 1.05rem; }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .back-to-top {
    bottom: 20px;
    right: 20px;
    width: 40px;
    height: 40px;
  }

  .subscribe-form { flex-direction: column; }
}

@media (max-width: 480px) {
  .container { padding: 0 16px; }
  .hero-text h1 { font-size: 1.35rem; }
  .hero-text p { font-size: 0.95rem; }
  .hero-img-placeholder { max-width: 220px; font-size: 3rem; }
}