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

:root {
  --bg-primary: #ffffff;
  --bg-secondary: #f8f9fa;
  --bg-tertiary: #f1f3f5;
  --bg-elevated: #ffffff;
  --text-primary: #212529;
  --text-secondary: #000000;
  --text-muted: #6c757d;
  --text-accent: #495057;
  --border-color: #dee2e6;
  --border-subtle: #e9ecef;
  --accent-color: #0066cc;
  --accent-hover: #0052a3;
  --hover-bg: #f8f9fa;
  --sidebar-width: 280px;
  --content-max-width: 1200px;
  --spacing-xs: 8px;
  --spacing-sm: 16px;
  --spacing-md: 24px;
  --spacing-lg: 32px;
  --spacing-xl: 48px;
  --spacing-2xl: 64px;
  --spacing-3xl: 96px;
  --radius-sm: 4px;
  --radius-md: 6px;
  --transition-fast: 0.15s ease;
  --transition-base: 0.2s ease;
  --transition-slow: 0.3s ease;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.7;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

.container {
  max-width: var(--content-max-width);
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}

header {
  background-color: var(--bg-primary);
  border-bottom: 1px solid var(--border-color);
  padding: var(--spacing-md) 0;
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: rgba(255, 255, 255, 0.98);
  backdrop-filter: blur(10px);
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.04);
  width: 100%;
}

.header-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: var(--spacing-xl);
  width: 100%;
  padding-left: var(--spacing-lg);
  padding-right: var(--spacing-lg);
}

.header-brand {
  flex-shrink: 0;
  text-align: left;
}

.logo {
  display: flex;
  flex-direction: column;
  text-decoration: none;
  transition: opacity var(--transition-base);
  align-items: flex-start;
  text-align: left;
}

.logo:hover {
  opacity: 0.8;
}

.logo-name {
  font-size: 20px;
  font-weight: 600;
  color: var(--text-secondary);
  line-height: 1.2;
  letter-spacing: -0.3px;
  transition: color var(--transition-base);
}

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

.logo-tagline {
  font-size: 12px;
  font-weight: 400;
  color: var(--text-muted);
  margin-top: 2px;
  letter-spacing: 0.3px;
  text-transform: uppercase;
}

.header-nav {
  display: flex;
  align-items: center;
  gap: var(--spacing-lg);
  flex-wrap: wrap;
}

.nav-link {
  font-size: 14px;
  font-weight: 400;
  color: var(--text-primary);
  text-decoration: none;
  padding: var(--spacing-xs) 0;
  position: relative;
  transition: color var(--transition-base);
  white-space: nowrap;
}

.nav-link::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background-color: var(--accent-color);
  transition: width var(--transition-base);
}

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

.nav-link:hover::after,
.nav-link.active::after {
  width: 100%;
}

.nav-link.active {
  color: var(--accent-color);
  font-weight: 500;
}

.main-layout {
  display: flex;
  min-height: calc(100vh - 73px);
}

.sidebar {
  width: var(--sidebar-width);
  background-color: var(--bg-secondary);
  border-right: 1px solid var(--border-color);
  padding: var(--spacing-2xl) var(--spacing-lg);
  position: fixed;
  height: calc(100vh - 73px);
  overflow-y: auto;
  top: 73px;
  scrollbar-width: thin;
  scrollbar-color: var(--border-color) transparent;
  scroll-margin-top: 100px;
}

.sidebar::-webkit-scrollbar {
  width: 4px;
}

.sidebar::-webkit-scrollbar-track {
  background: transparent;
}

.sidebar::-webkit-scrollbar-thumb {
  background-color: var(--border-color);
  border-radius: 2px;
}

.sidebar::-webkit-scrollbar-thumb:hover {
  background-color: var(--text-muted);
}

.sidebar h2 {
  color: var(--text-secondary);
  font-size: 14px;
  font-weight: 600;
  margin-bottom: var(--spacing-xl);
  padding-bottom: var(--spacing-sm);
  border-bottom: 1px solid var(--border-color);
  letter-spacing: 0.5px;
  text-transform: uppercase;
}

.sidebar .author-name {
  color: var(--text-secondary);
  font-size: 20px;
  font-weight: 500;
  margin-bottom: var(--spacing-lg);
  letter-spacing: -0.3px;
  line-height: 1.4;
}

.sidebar .author-bio {
  font-size: 14px;
  line-height: 1.8;
  margin-bottom: var(--spacing-2xl);
  color: var(--text-primary);
}

.sidebar .author-bio p {
  margin-bottom: var(--spacing-md);
}

.sidebar .author-bio p:last-child {
  margin-bottom: 0;
}

.sidebar .author-experience {
  margin-top: var(--spacing-2xl);
  padding-top: var(--spacing-xl);
  border-top: 1px solid var(--border-color);
}

.sidebar .author-experience h3 {
  color: var(--text-secondary);
  font-size: 13px;
  font-weight: 600;
  margin-bottom: var(--spacing-md);
  letter-spacing: 0.3px;
  text-transform: uppercase;
}

.sidebar .author-experience ul {
  list-style: none;
  padding-left: 0;
}

.sidebar .author-experience li {
  font-size: 14px;
  line-height: 1.8;
  margin-bottom: var(--spacing-sm);
  padding-left: 0;
  position: relative;
  color: var(--text-primary);
}

.main-content {
  flex: 1;
  margin-left: var(--sidebar-width);
  padding: var(--spacing-3xl) var(--spacing-2xl);
  max-width: calc(100% - var(--sidebar-width));
}

.search-section {
  margin-bottom: var(--spacing-3xl);
}

.search-box {
  width: 100%;
  max-width: 600px;
  margin: 0 auto;
  position: relative;
}

.search-box input {
  width: 100%;
  padding: 16px 20px;
  background-color: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-size: 15px;
  transition: all var(--transition-base);
  font-family: inherit;
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.04);
}

.search-box input:focus {
  outline: none;
  border-color: var(--accent-color);
  box-shadow: 0 0 0 3px rgba(0, 102, 204, 0.08);
}

.search-box input::placeholder {
  color: var(--text-muted);
  font-weight: 400;
}

.search-results-count {
  text-align: center;
  margin-top: var(--spacing-md);
  font-size: 13px;
  color: var(--text-muted);
  font-weight: 400;
}

.articles-section {
  scroll-margin-top: 100px;
}

.articles-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: var(--spacing-xl);
  margin-top: 0;
}


.article-card {
  background-color: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: var(--spacing-xl);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
  cursor: pointer;
  text-decoration: none;
  color: inherit;
  display: flex;
  flex-direction: column;
  height: 100%;
  position: relative;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.04);
}

.article-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
}

.article-card h3 {
  color: var(--text-secondary);
  font-size: 20px;
  font-weight: 500;
  margin-bottom: var(--spacing-md);
  line-height: 1.4;
  letter-spacing: -0.2px;
  transition: color var(--transition-base);
}

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

.article-card .article-meta {
  font-size: 12px;
  color: var(--text-muted);
  margin-bottom: var(--spacing-lg);
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  font-weight: 400;
  text-transform: none;
  letter-spacing: 0;
}

.article-card .article-description {
  font-size: 15px;
  line-height: 1.7;
  margin-bottom: var(--spacing-xl);
  color: var(--text-primary);
  flex-grow: 1;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
  font-weight: 400;
}

.article-card .article-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-xs);
  margin-top: auto;
  padding-top: var(--spacing-lg);
  border-top: 1px solid var(--border-subtle);
}

.article-card .tag {
  background-color: var(--bg-secondary);
  color: var(--text-primary);
  padding: 5px 12px;
  border-radius: var(--radius-sm);
  font-size: 11px;
  font-weight: 400;
  border: 1px solid var(--border-subtle);
  transition: all var(--transition-fast);
  text-transform: none;
  letter-spacing: 0;
}

.article-card:hover .tag {
  background-color: var(--bg-tertiary);
  border-color: var(--border-color);
}

.no-results {
  text-align: center;
  padding: var(--spacing-3xl) var(--spacing-2xl);
  color: var(--text-muted);
  font-size: 15px;
  grid-column: 1 / -1;
  font-weight: 400;
}

.no-results-icon {
  font-size: 40px;
  margin-bottom: var(--spacing-lg);
  opacity: 0.4;
}

.article-content {
  max-width: 720px;
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}

.article-content h1 {
  color: var(--text-secondary);
  font-size: 36px;
  font-weight: 500;
  margin-bottom: var(--spacing-md);
  line-height: 1.3;
  letter-spacing: -0.5px;
}

.article-content .article-header {
  margin-bottom: var(--spacing-3xl);
  padding-bottom: var(--spacing-xl);
  border-bottom: 1px solid var(--border-color);
}

.article-content .article-meta {
  color: var(--text-muted);
  font-size: 13px;
  margin-bottom: var(--spacing-md);
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  font-weight: 400;
  text-transform: none;
  letter-spacing: 0;
}

.article-content .article-body {
  font-size: 17px;
  line-height: 1.8;
  color: var(--text-primary);
  font-weight: 400;
}

.article-content .article-body h2 {
  color: var(--text-secondary);
  font-size: 28px;
  font-weight: 500;
  margin-top: var(--spacing-3xl);
  margin-bottom: var(--spacing-xl);
  padding-bottom: var(--spacing-md);
  border-bottom: 1px solid var(--border-color);
  letter-spacing: -0.3px;
  line-height: 1.4;
}

.article-content .article-body h3 {
  color: var(--text-secondary);
  font-size: 22px;
  font-weight: 500;
  margin-top: var(--spacing-2xl);
  margin-bottom: var(--spacing-lg);
  letter-spacing: -0.2px;
  line-height: 1.4;
}

.article-content .article-body h4 {
  color: var(--text-secondary);
  font-size: 18px;
  font-weight: 500;
  margin-top: var(--spacing-xl);
  margin-bottom: var(--spacing-md);
  letter-spacing: -0.1px;
}

.article-content .article-body p {
  margin-bottom: var(--spacing-xl);
  color: var(--text-primary);
}

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

.article-content .article-body ul {
  list-style: none;
}

.article-content .article-body ul li {
  position: relative;
  padding-left: var(--spacing-md);
  margin-bottom: var(--spacing-md);
}

.article-content .article-body ul li::before {
  content: "•";
  position: absolute;
  left: 0;
  color: var(--text-muted);
  font-size: 16px;
  font-weight: bold;
}

.article-content .article-body ol li {
  margin-bottom: var(--spacing-md);
  padding-left: var(--spacing-xs);
}

.article-content .article-body a {
  color: var(--accent-color);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: all var(--transition-base);
  font-weight: 400;
}

.article-content .article-body a:hover {
  border-bottom-color: var(--accent-color);
  color: var(--accent-hover);
}

.article-content .article-body code {
  background-color: var(--bg-secondary);
  padding: 3px 6px;
  border-radius: var(--radius-sm);
  font-family: 'SF Mono', 'Monaco', 'Courier New', monospace;
  font-size: 14px;
  border: 1px solid var(--border-subtle);
  color: var(--text-primary);
}

.article-content .article-body pre {
  background-color: var(--bg-secondary);
  padding: var(--spacing-xl);
  border-radius: var(--radius-sm);
  overflow-x: auto;
  margin-bottom: var(--spacing-xl);
  margin-top: var(--spacing-lg);
  border: 1px solid var(--border-color);
  position: relative;
}

.article-content .article-body pre code {
  background: none;
  padding: 0;
  border: none;
  color: var(--text-primary);
  font-size: 14px;
  line-height: 1.6;
}

.article-content .back-link {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
  margin-top: var(--spacing-3xl);
  padding: var(--spacing-sm) var(--spacing-md);
  background-color: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  text-decoration: none;
  font-size: 14px;
  font-weight: 400;
  transition: all var(--transition-base);
}

.article-content .back-link::before {
  content: "←";
  font-size: 16px;
}

.article-content .back-link:hover {
  background-color: var(--bg-secondary);
  border-color: var(--accent-color);
  color: var(--accent-color);
}

footer {
  background-color: var(--bg-secondary);
  border-top: 1px solid var(--border-color);
  padding: var(--spacing-2xl) 0;
  margin-top: var(--spacing-3xl);
  text-align: center;
  color: var(--text-muted);
  font-size: 13px;
  margin-left: var(--sidebar-width);
  font-weight: 400;
}

.loading {
  text-align: center;
  padding: var(--spacing-3xl) var(--spacing-2xl);
  color: var(--text-muted);
  font-size: 14px;
  grid-column: 1 / -1;
  font-weight: 400;
}

.loading::after {
  content: "...";
  animation: dots 1.5s steps(4, end) infinite;
}

@keyframes dots {
  0%, 20% { content: "."; }
  40% { content: ".."; }
  60%, 100% { content: "..."; }
}

.article-card {
  opacity: 1;
}


@media (max-width: 1024px) {
  .main-content {
    padding: var(--spacing-2xl) var(--spacing-lg);
  }
  
  .articles-grid {
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: var(--spacing-lg);
  }
  
  .article-content {
    padding: 0 var(--spacing-md);
  }
}

@media (max-width: 768px) {
  :root {
    --sidebar-width: 100%;
  }

  .header-content {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--spacing-md);
  }

  .header-nav {
    width: 100%;
    gap: var(--spacing-md);
    padding-top: var(--spacing-sm);
    border-top: 1px solid var(--border-subtle);
  }

  .nav-link {
    font-size: 13px;
  }

  .main-layout {
    flex-direction: column;
  }

  .sidebar {
    position: relative;
    width: 100%;
    height: auto;
    top: 0;
    border-right: none;
    border-bottom: 1px solid var(--border-color);
    padding: var(--spacing-xl) var(--spacing-lg);
  }

  .main-content {
    margin-left: 0;
    padding: var(--spacing-xl) var(--spacing-lg);
    max-width: 100%;
  }

  .articles-grid {
    grid-template-columns: 1fr;
    gap: var(--spacing-lg);
  }

  .article-content {
    padding: 0;
  }

  .article-content h1 {
    font-size: 28px;
    margin-bottom: var(--spacing-sm);
  }

  .article-content .article-header {
    margin-bottom: var(--spacing-2xl);
    padding-bottom: var(--spacing-lg);
  }

  .article-content .article-body h2 {
    font-size: 24px;
    margin-top: var(--spacing-2xl);
    margin-bottom: var(--spacing-lg);
  }

  .article-content .article-body h3 {
    font-size: 20px;
    margin-top: var(--spacing-xl);
    margin-bottom: var(--spacing-md);
  }

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

  .article-content .article-body ul,
  .article-content .article-body ol {
    margin-bottom: var(--spacing-lg);
  }

  .search-box {
    max-width: 100%;
  }

  footer {
    margin-left: 0;
    padding: var(--spacing-xl) 0;
    margin-top: var(--spacing-2xl);
  }
}

@media (max-width: 480px) {
  .article-card {
    padding: var(--spacing-lg);
  }

  .article-card h3 {
    font-size: 18px;
    margin-bottom: var(--spacing-sm);
  }

  .article-card .article-meta {
    margin-bottom: var(--spacing-md);
  }

  .article-card .article-description {
    margin-bottom: var(--spacing-lg);
  }

  .article-card .article-tags {
    padding-top: var(--spacing-md);
  }

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

  .search-section {
    margin-bottom: var(--spacing-2xl);
  }

  .articles-grid {
    gap: var(--spacing-md);
  }
}