:root {
  --primary-color: #0d9488;
  --primary-hover: #0f766e;
  --primary-light: #ccfbf1;
  --primary-glow: rgba(13, 148, 136, 0.2);
  
  --bg-main: #f8fafc;
  --bg-card: #ffffff;
  --bg-alt: #f1f5f9;
  
  --text-main: #0f172a;
  --text-muted: #64748b;
  --text-subtle: #94a3b8;
  
  --border-color: #e2e8f0;
  --border-hover: #cbd5e1;
  
  --hero-bg: linear-gradient(135deg, #090d16 0%, #111827 50%, #064e3b 100%);
  --hero-text: #ffffff;
  
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 18px;
  --radius-full: 9999px;
  
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
  --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
  
  --transition-fast: 0.15s ease;
  --transition-normal: 0.25s cubic-bezier(0.16, 1, 0.3, 1);
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, "Open Sans", "Helvetica Neue", sans-serif;
  background-color: var(--bg-main);
  color: var(--text-main);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

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

a:hover {
  color: var(--primary-hover);
  text-decoration: underline;
}

/* Header & Navigation */
.site-header {
  background: var(--hero-bg);
  color: var(--hero-text);
  padding: 24px 20px 70px 20px;
  position: relative;
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.nav-container {
  max-width: 1140px;
  margin: 0 auto 40px auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.brand-logo {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  color: #ffffff;
  font-weight: 700;
  font-size: 1.25rem;
  letter-spacing: -0.02em;
}

.brand-logo:hover {
  text-decoration: none;
  color: #ffffff;
}

.logo-icon {
  width: 40px;
  height: 40px;
  border-radius: 10px;
  background: linear-gradient(135deg, #0d9488, #14b8a6);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #ffffff;
  box-shadow: 0 4px 12px rgba(13, 148, 136, 0.4);
}

.logo-icon svg {
  width: 22px;
  height: 22px;
}

.brand-tag {
  font-size: 0.75rem;
  background: rgba(20, 184, 166, 0.2);
  color: #2dd4bf;
  padding: 3px 8px;
  border-radius: 4px;
  font-weight: 600;
  border: 1px solid rgba(45, 212, 191, 0.3);
}

.nav-links {
  display: flex;
  gap: 16px;
  align-items: center;
}

.nav-btn {
  color: rgba(255, 255, 255, 0.85);
  font-size: 0.9rem;
  font-weight: 500;
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
}

.nav-btn:hover {
  background: rgba(255, 255, 255, 0.1);
  color: #ffffff;
  text-decoration: none;
}

.nav-btn-primary {
  background: #0d9488;
  color: #ffffff !important;
}

.nav-btn-primary:hover {
  background: #0f766e;
}

/* Hero Section */
.hero-content {
  max-width: 760px;
  margin: 0 auto;
  text-align: center;
}

.hero-title {
  font-size: 2.5rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  margin-bottom: 12px;
  line-height: 1.2;
}

.hero-subtitle {
  font-size: 1.15rem;
  color: rgba(255, 255, 255, 0.75);
  margin-bottom: 32px;
}

/* Search Box */
.search-wrapper {
  position: relative;
  max-width: 640px;
  margin: 0 auto;
}

.search-input-box {
  position: relative;
  display: flex;
  align-items: center;
}

.search-icon {
  position: absolute;
  left: 20px;
  width: 20px;
  height: 20px;
  color: var(--text-subtle);
  pointer-events: none;
}

.search-input {
  width: 100%;
  padding: 16px 20px 16px 54px;
  font-size: 1.05rem;
  border: 1px solid rgba(255, 255, 255, 0.15);
  border-radius: var(--radius-md);
  background: #ffffff;
  color: var(--text-main);
  box-shadow: var(--shadow-xl);
  outline: none;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.search-input:focus {
  border-color: #14b8a6;
  box-shadow: 0 0 0 4px rgba(20, 184, 166, 0.25), var(--shadow-xl);
}

.clear-search-btn {
  position: absolute;
  right: 16px;
  background: none;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  padding: 4px;
  display: none;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-full);
}

.clear-search-btn:hover {
  background: var(--bg-alt);
  color: var(--text-main);
}

/* Main Container */
.main-container {
  max-width: 1140px;
  margin: -35px auto 80px auto;
  padding: 0 20px;
  position: relative;
  z-index: 10;
}

/* Section Header */
.section-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
  margin-bottom: 24px;
}

.section-title {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--text-main);
  letter-spacing: -0.02em;
}

.section-counter {
  font-size: 0.9rem;
  color: var(--text-muted);
  font-weight: 500;
}

/* Collection Cards Grid */
.collections-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
  gap: 20px;
  margin-bottom: 60px;
}

.collection-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 24px;
  cursor: pointer;
  transition: transform var(--transition-fast), box-shadow var(--transition-fast), border-color var(--transition-fast);
  display: flex;
  flex-direction: column;
  box-shadow: var(--shadow-sm);
  text-decoration: none !important;
  color: inherit;
}

.collection-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
  border-color: #99f6e4;
}

.collection-header {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 14px;
}

.collection-badge-icon {
  width: 44px;
  height: 44px;
  border-radius: 10px;
  background: var(--primary-light);
  color: var(--primary-color);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.collection-badge-icon svg {
  width: 24px;
  height: 24px;
}

.collection-card-title {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text-main);
  line-height: 1.3;
}

.collection-card-desc {
  font-size: 0.92rem;
  color: var(--text-muted);
  line-height: 1.5;
  margin-bottom: 18px;
  flex-grow: 1;
}

.collection-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: 14px;
  border-top: 1px solid var(--border-color);
  font-size: 0.85rem;
  color: var(--text-muted);
  font-weight: 500;
}

.collection-arrow {
  color: var(--primary-color);
  display: flex;
  align-items: center;
  gap: 4px;
  font-weight: 600;
}

/* Search Results View */
.search-results-container {
  display: none;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 30px;
  box-shadow: var(--shadow-md);
  margin-bottom: 50px;
}

.results-header {
  margin-bottom: 24px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border-color);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.results-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.result-item {
  padding: 16px 20px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-color);
  transition: background var(--transition-fast), border-color var(--transition-fast);
  cursor: pointer;
  text-decoration: none !important;
  display: block;
}

.result-item:hover {
  background: var(--bg-main);
  border-color: #14b8a6;
}

.result-category {
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--primary-color);
  font-weight: 700;
  margin-bottom: 4px;
}

.result-title {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text-main);
  margin-bottom: 6px;
}

.result-snippet {
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.5;
}

/* Category & Article Views */
.view-container {
  display: none;
}

.breadcrumb-nav {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.9rem;
  color: var(--text-muted);
  margin-bottom: 24px;
  flex-wrap: wrap;
}

.breadcrumb-nav a {
  color: var(--text-muted);
  font-weight: 500;
}

.breadcrumb-nav a:hover {
  color: var(--primary-color);
}

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

/* Article Reading Layout */
.article-layout {
  display: grid;
  grid-template-columns: 1fr 280px;
  gap: 36px;
  align-items: start;
}

@media (max-width: 900px) {
  .article-layout {
    grid-template-columns: 1fr;
  }
  .article-sidebar {
    display: none;
  }
}

.article-content-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 40px;
  box-shadow: var(--shadow-sm);
}

.article-page-title {
  font-size: 2.2rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  color: var(--text-main);
  line-height: 1.25;
  margin-bottom: 12px;
}

.article-page-desc {
  font-size: 1.1rem;
  color: var(--text-muted);
  line-height: 1.5;
  margin-bottom: 28px;
  padding-bottom: 24px;
  border-bottom: 1px solid var(--border-color);
}

/* Article Body Content Styling */
.article-body {
  font-size: 1.05rem;
  line-height: 1.7;
  color: #1e293b;
}

.article-body h1, .article-body h2, .article-body h3, .article-body h4 {
  color: var(--text-main);
  margin-top: 36px;
  margin-bottom: 16px;
  font-weight: 700;
  line-height: 1.3;
}

.article-body h1 { font-size: 1.6rem; }
.article-body h2 { font-size: 1.4rem; }
.article-body h3 { font-size: 1.2rem; }

.article-body p {
  margin-bottom: 20px;
}

.article-body ul, .article-body ol {
  margin: 0 0 24px 28px;
}

.article-body li {
  margin-bottom: 8px;
}

.article-body img {
  max-width: 100%;
  height: auto;
  border-radius: var(--radius-sm);
  margin: 24px 0;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
  border: 1px solid var(--border-color);
  display: block;
}

.article-body blockquote {
  border-left: 4px solid var(--primary-color);
  padding: 12px 20px;
  background: var(--bg-alt);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin: 24px 0;
  color: var(--text-muted);
}

.article-body code {
  background: var(--bg-alt);
  padding: 2px 6px;
  border-radius: 4px;
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
  font-size: 0.9em;
  color: #be185d;
}

/* Sidebar */
.sidebar-box {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 24px;
  margin-bottom: 24px;
  box-shadow: var(--shadow-sm);
}

.sidebar-title {
  font-size: 0.95rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-muted);
  margin-bottom: 16px;
}

.related-articles-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.related-articles-list li {
  margin-bottom: 12px;
}

.related-articles-list a {
  display: block;
  font-size: 0.92rem;
  color: var(--text-main);
  font-weight: 500;
  line-height: 1.4;
}

.related-articles-list a:hover {
  color: var(--primary-color);
}

.support-banner {
  background: linear-gradient(135deg, #f0fdfa, #ccfbf1);
  border: 1px solid #99f6e4;
  border-radius: var(--radius-md);
  padding: 24px;
  text-align: center;
}

.support-banner h4 {
  font-size: 1.05rem;
  font-weight: 700;
  color: #0f766e;
  margin-bottom: 8px;
}

.support-banner p {
  font-size: 0.88rem;
  color: #115e59;
  margin-bottom: 16px;
}

.support-btn {
  display: inline-block;
  background: #0d9488;
  color: #ffffff !important;
  font-weight: 600;
  font-size: 0.9rem;
  padding: 8px 18px;
  border-radius: var(--radius-sm);
  box-shadow: 0 2px 6px rgba(13, 148, 136, 0.3);
}

.support-btn:hover {
  background: #0f766e;
  text-decoration: none;
}

/* Category View - Articles List */
.category-articles-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 16px;
}

.article-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 20px;
  cursor: pointer;
  transition: all var(--transition-fast);
  text-decoration: none !important;
  color: inherit;
  display: flex;
  flex-direction: column;
}

.article-card:hover {
  border-color: #14b8a6;
  box-shadow: var(--shadow-sm);
  transform: translateY(-2px);
}

.article-card-title {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text-main);
  margin-bottom: 8px;
  line-height: 1.4;
}

.article-card-desc {
  font-size: 0.88rem;
  color: var(--text-muted);
  line-height: 1.5;
  flex-grow: 1;
}

/* Footer */
.site-footer {
  background: #ffffff;
  border-top: 1px solid var(--border-color);
  padding: 40px 20px;
  margin-top: 80px;
  font-size: 0.9rem;
  color: var(--text-muted);
}

.footer-inner {
  max-width: 1140px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 20px;
}

.footer-links {
  display: flex;
  gap: 20px;
}

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

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