:root {
  --primary-color: #2563eb;
  --primary-hover: #1d4ed8;
  --text-primary: #1f2937;
  --text-secondary: #6b7280;
  --bg-primary: #ffffff;
  --bg-secondary: #f9fafb;
  --border-color: #e5e7eb;
  --shadow-sm: 0 1px 2px 0 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);
  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --max-width: 1280px;
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 1.5rem;
  --spacing-lg: 2rem;
  --spacing-xl: 3rem;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  font-size: 16px;
  line-height: 1.6;
  color: var(--text-primary);
  background-color: var(--bg-secondary);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

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

ul {
  list-style: none;
}

.header {
  background-color: var(--bg-primary);
  box-shadow: var(--shadow-sm);
  position: sticky;
  top: 0;
  z-index: 1000;
  border-bottom: 1px solid var(--border-color);
}

.nav-container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: var(--spacing-sm) var(--spacing-md);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo a {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--primary-color);
  letter-spacing: -0.02em;
}

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

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

.nav-links a {
  font-weight: 500;
  color: var(--text-secondary);
  position: relative;
  padding: var(--spacing-xs) 0;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background-color: var(--primary-color);
  transition: width 0.3s ease;
}

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

.nav-links a:hover::after {
  width: 100%;
}

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

.nav-links a.active::after {
  width: 100%;
}

.mobile-menu-toggle {
  display: none;
  flex-direction: column;
  gap: 4px;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--spacing-xs);
}

.mobile-menu-toggle span {
  width: 24px;
  height: 2px;
  background-color: var(--text-primary);
  transition: var(--transition);
}

.main-content {
  min-height: calc(100vh - 180px);
}

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

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

.section-title {
  font-size: 2rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: var(--spacing-lg);
  letter-spacing: -0.02em;
  line-height: 1.2;
}

.page-title {
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: var(--spacing-sm);
  letter-spacing: -0.02em;
  line-height: 1.2;
}

.page-description {
  font-size: 1.125rem;
  color: var(--text-secondary);
  margin-bottom: var(--spacing-xl);
  line-height: 1.6;
  max-width: 700px;
}

.blog-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: var(--spacing-lg);
}

.blog-card {
  background-color: var(--bg-primary);
  border-radius: 12px;
  overflow: hidden;
  box-shadow: var(--shadow-md);
  transition: var(--transition);
  cursor: pointer;
  border: 1px solid var(--border-color);
}

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

.blog-card:focus-within {
  outline: 2px solid var(--primary-color);
  outline-offset: 2px;
}

.blog-card-image {
  width: 100%;
  height: 220px;
  overflow: hidden;
  background-color: var(--bg-secondary);
}

.blog-card-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.5s ease;
}

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

.blog-card-content {
  padding: var(--spacing-md);
}

.blog-card-title {
  font-size: 1.125rem;
  font-weight: 600;
  line-height: 1.4;
  color: var(--text-primary);
  margin: 0;
}

.blog-card-title a {
  color: var(--text-primary);
  display: block;
}

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

.blog-card-title a:focus {
  outline: 2px solid var(--primary-color);
  outline-offset: 2px;
  border-radius: 4px;
}

.blog-card-description {
  font-size: 0.9375rem;
  line-height: 1.6;
  color: var(--text-secondary);
  margin-top: var(--spacing-sm);
}

.search-filter-wrapper {
  margin-bottom: var(--spacing-xl);
  background-color: var(--bg-primary);
  border-radius: 12px;
  padding: var(--spacing-lg);
  box-shadow: var(--shadow-md);
  border: 1px solid var(--border-color);
}

.search-container {
  margin-bottom: var(--spacing-md);
}

.search-input-wrapper {
  position: relative;
  max-width: 100%;
}

.search-icon {
  position: absolute;
  left: 16px;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-secondary);
  pointer-events: none;
}

.search-input {
  width: 100%;
  padding: 14px 16px 14px 48px;
  font-size: 1rem;
  border: 2px solid var(--border-color);
  border-radius: 8px;
  background-color: var(--bg-secondary);
  color: var(--text-primary);
  transition: var(--transition);
  font-family: inherit;
}

.search-input:focus {
  outline: none;
  border-color: var(--primary-color);
  background-color: var(--bg-primary);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.search-input::placeholder {
  color: var(--text-secondary);
}

.filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-md);
  align-items: flex-end;
}

.filter-controls {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-md);
  flex: 1;
}

.filter-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
  min-width: 160px;
  flex: 1;
}

.filter-label {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text-primary);
}

.filter-select {
  padding: 10px 36px 10px 12px;
  font-size: 0.9375rem;
  border: 2px solid var(--border-color);
  border-radius: 8px;
  background-color: var(--bg-secondary);
  color: var(--text-primary);
  cursor: pointer;
  transition: var(--transition);
  font-family: inherit;
  appearance: none;
  background-image: url('data:image/svg+xml;charset=UTF-8,<svg width="12" height="8" viewBox="0 0 12 8" fill="none" xmlns="http://www.w3.org/2000/svg"><path d="M1 1.5L6 6.5L11 1.5" stroke="%236b7280" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"/></svg>');
  background-repeat: no-repeat;
  background-position: right 12px center;
}

.filter-select:hover {
  border-color: var(--primary-color);
  background-color: var(--bg-primary);
}

.filter-select:focus {
  outline: none;
  border-color: var(--primary-color);
  background-color: var(--bg-primary);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.filter-select option {
  padding: 10px;
}

.clear-filters-btn {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 10px 20px;
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--text-secondary);
  background-color: var(--bg-secondary);
  border: 2px solid var(--border-color);
  border-radius: 8px;
  cursor: pointer;
  transition: var(--transition);
  font-family: inherit;
  white-space: nowrap;
}

.clear-filters-btn:hover {
  color: var(--primary-color);
  border-color: var(--primary-color);
  background-color: rgba(37, 99, 235, 0.05);
}

.clear-filters-btn:focus {
  outline: none;
  border-color: var(--primary-color);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.clear-filters-btn:active {
  transform: scale(0.98);
}

.clear-filters-btn svg {
  width: 16px;
  height: 16px;
}

.active-filters {
  margin-top: var(--spacing-md);
  padding-top: var(--spacing-md);
  border-top: 1px solid var(--border-color);
}

.active-filters-label {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-right: var(--spacing-sm);
}

.active-filters-list {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-xs);
  margin-top: var(--spacing-xs);
}

.filter-tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 12px;
  font-size: 0.875rem;
  color: var(--primary-color);
  background-color: rgba(37, 99, 235, 0.1);
  border: 1px solid rgba(37, 99, 235, 0.2);
  border-radius: 6px;
  transition: var(--transition);
}

.filter-tag:hover {
  background-color: rgba(37, 99, 235, 0.15);
}

.filter-tag button {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0;
  background: none;
  border: none;
  color: var(--primary-color);
  cursor: pointer;
  transition: var(--transition);
}

.filter-tag button:hover {
  color: var(--primary-hover);
}

.filter-tag svg {
  width: 14px;
  height: 14px;
}

.footer {
  background-color: var(--bg-primary);
  border-top: 1px solid var(--border-color);
  padding: var(--spacing-lg) 0;
  margin-top: var(--spacing-xl);
}

.footer p {
  text-align: center;
  color: var(--text-secondary);
  font-size: 0.875rem;
}

@media (max-width: 768px) {
  .nav-container {
    padding: var(--spacing-sm);
  }

  .mobile-menu-toggle {
    display: flex;
    z-index: 1001;
  }

  .mobile-menu-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
  }

  .mobile-menu-toggle.active span:nth-child(2) {
    opacity: 0;
  }

  .mobile-menu-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(7px, -7px);
  }

  .nav-links {
    position: fixed;
    top: 60px;
    left: 0;
    right: 0;
    flex-direction: column;
    background-color: var(--bg-primary);
    padding: var(--spacing-lg);
    gap: var(--spacing-md);
    box-shadow: var(--shadow-lg);
    transform: translateX(-100%);
    transition: transform 0.3s ease;
  }

  .nav-links.active {
    transform: translateX(0);
  }

  .nav-links a::after {
    display: none;
  }

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

  .section-title {
    font-size: 1.75rem;
    margin-bottom: var(--spacing-md);
  }

  .page-title {
    font-size: 2rem;
  }

  .page-description {
    font-size: 1rem;
    margin-bottom: var(--spacing-lg);
  }

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

  .blog-card-image {
    height: 200px;
  }

  .blog-card-title {
    font-size: 1rem;
  }

  .search-filter-wrapper {
    padding: var(--spacing-md);
  }

  .filter-bar {
    flex-direction: column;
    align-items: stretch;
  }

  .filter-controls {
    flex-direction: column;
  }

  .filter-group {
    min-width: 100%;
  }

  .clear-filters-btn {
    width: 100%;
    justify-content: center;
  }

  .active-filters-label {
    display: block;
    margin-bottom: var(--spacing-xs);
  }
}

@media (min-width: 769px) and (max-width: 1024px) {
  .blog-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 1025px) {
  .blog-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

@media (min-width: 1400px) {
  .blog-grid {
    grid-template-columns: repeat(4, 1fr);
  }
}

@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}