/* 
 * AI Tools Directory - Main Stylesheet
 * A modern, clean design system for categorizing AI tools
 */

/* ===== BASE STYLES ===== */
:root {
  /* Color Palette */
  --primary-color: #4361ee;
  --primary-light: #4895ef;
  --secondary-color: #3f37c9;
  --accent-color: #4cc9f0;
  --dark-color: #1d3557;
  --light-color: #f8f9fa;
  --gray-100: #f8f9fa;
  --gray-200: #e9ecef;
  --gray-300: #dee2e6;
  --gray-400: #ced4da;
  --gray-500: #adb5bd;
  --gray-600: #6c757d;
  --gray-700: #495057;
  --gray-800: #343a40;
  --gray-900: #212529;
  
  /* Typography */
  --font-family-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
  --font-family-mono: 'JetBrains Mono', SFMono-Regular, Menlo, Monaco, Consolas, 'Liberation Mono', 'Courier New', monospace;
  
  /* Spacing */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-xxl: 3rem;
  
  /* Border Radius */
  --border-radius-sm: 0.25rem;
  --border-radius-md: 0.5rem;
  --border-radius-lg: 1rem;
  
  /* Shadows */
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.12), 0 1px 2px rgba(0, 0, 0, 0.24);
  --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  
  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-normal: 300ms ease;
  --transition-slow: 500ms ease;
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-family-sans);
  line-height: 1.6;
  color: var(--gray-800);
  background-color: var(--gray-100);
}

.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--spacing-md);
}

/* ===== TYPOGRAPHY ===== */
h1, h2, h3, h4, h5, h6 {
  margin-bottom: var(--spacing-md);
  line-height: 1.2;
  color: var(--dark-color);
  font-weight: 700;
}

h1 {
  font-size: 2.5rem;
}

h2 {
  font-size: 2rem;
}

h3 {
  font-size: 1.75rem;
}

p {
  margin-bottom: var(--spacing-md);
}

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

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

/* ===== HEADER ===== */
header {
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  color: white;
  padding: var(--spacing-xl) 0;
  text-align: center;
  box-shadow: var(--shadow-md);
}

header h1 {
  color: white;
  margin-bottom: var(--spacing-sm);
  font-size: 2.75rem;
}

header p {
  font-size: 1.2rem;
  opacity: 0.9;
}

/* ===== NAVIGATION ===== */
.filter-nav {
  background-color: white;
  padding: var(--spacing-md) 0;
  box-shadow: var(--shadow-sm);
  position: sticky;
  top: 0;
  z-index: 100;
}

.filter-nav .container {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: var(--spacing-md);
}

.search-container {
  display: flex;
  flex: 1;
  max-width: 500px;
  position: relative;
}

.search-container input {
  flex: 1;
  padding: var(--spacing-sm) var(--spacing-md);
  border: 1px solid var(--gray-300);
  border-radius: var(--border-radius-md) 0 0 var(--border-radius-md);
  font-size: 1rem;
}

.search-container button {
  background-color: var(--primary-color);
  color: white;
  border: none;
  padding: var(--spacing-sm) var(--spacing-md);
  cursor: pointer;
  border-radius: 0 var(--border-radius-md) var(--border-radius-md) 0;
  transition: background-color var(--transition-fast);
}

.search-container button:hover {
  background-color: var(--primary-light);
}

/* Clear search button */
.clear-search-btn {
  position: absolute;
  right: 60px;
  top: 50%;
  transform: translateY(-50%);
  background: none;
  border: none;
  color: var(--gray-600);
  cursor: pointer;
  font-size: 1rem;
  padding: var(--spacing-xs);
  display: none;
}

.clear-search-btn:hover {
  color: var(--gray-800);
}

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

.filter-container select {
  padding: var(--spacing-sm) var(--spacing-md);
  border: 1px solid var(--gray-300);
  border-radius: var(--border-radius-md);
  font-size: 1rem;
  background-color: white;
}

/* ===== QUICK FILTER BUTTONS ===== */
.quick-filter-container {
  margin: var(--spacing-lg) 0;
  background-color: white;
  padding: var(--spacing-md);
  border-radius: var(--border-radius-md);
  box-shadow: var(--shadow-sm);
}

.quick-filter-container h3 {
  margin-bottom: var(--spacing-sm);
  font-size: 1.2rem;
  color: var(--gray-700);
}

.quick-filter-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
}

.quick-filter-btn {
  background-color: var(--gray-200);
  border: none;
  padding: var(--spacing-sm) var(--spacing-md);
  border-radius: var(--border-radius-md);
  cursor: pointer;
  font-size: 0.9rem;
  transition: all var(--transition-fast);
}

.quick-filter-btn:hover {
  background-color: var(--gray-300);
}

.quick-filter-btn.active {
  background-color: var(--primary-color);
  color: white;
}

/* ===== MAIN CONTENT ===== */
main {
  padding: var(--spacing-xl) 0;
}

#tools-container {
  display: grid;
  gap: var(--spacing-xl);
}

.category-section {
  background-color: white;
  border-radius: var(--border-radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-md);
  transition: transform var(--transition-normal);
}

.category-section:hover {
  transform: translateY(-5px);
}

.category-header {
  background: linear-gradient(135deg, var(--primary-light), var(--accent-color));
  color: white;
  padding: var(--spacing-md) var(--spacing-lg);
  border-radius: var(--border-radius-lg) var(--border-radius-lg) 0 0;
}

.category-title-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.category-header h2 {
  margin-bottom: 0;
  color: white;
}

.category-info {
  margin-top: var(--spacing-xs);
  font-size: 0.9rem;
  opacity: 0.9;
}

.tool-count {
  display: inline-block;
  background-color: rgba(255, 255, 255, 0.2);
  padding: 0.1rem 0.5rem;
  border-radius: var(--border-radius-sm);
}

/* Collapse button */
.collapse-btn {
  background: none;
  border: none;
  color: white;
  cursor: pointer;
  font-size: 1.2rem;
  width: 30px;
  height: 30px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  transition: background-color var(--transition-fast);
}

.collapse-btn:hover {
  background-color: rgba(255, 255, 255, 0.2);
}

.tools-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
  gap: var(--spacing-md);
  padding: var(--spacing-lg);
  max-height: 2000px; /* Large enough to contain all tools */
  overflow: hidden;
  transition: max-height var(--transition-normal);
}

.tools-grid.collapsed {
  max-height: 0;
  padding-top: 0;
  padding-bottom: 0;
}

.tool-card {
  display: block;
  text-decoration: none;
  background-color: var(--gray-100);
  border-radius: var(--border-radius-md);
  padding: var(--spacing-md);
  color: var(--gray-800);
  border: 1px solid var(--gray-300);
  transition: all var(--transition-normal);
  text-align: center;
}

.tool-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
  border-color: var(--primary-light);
  background-color: white;
}

.tool-card h3 {
  font-size: 1.1rem;
  margin-bottom: var(--spacing-xs);
  color: var(--primary-color);
}

.tool-card p {
  font-size: 0.9rem;
  color: var(--gray-600);
  margin-bottom: 0;
}

.loading {
  text-align: center;
  padding: var(--spacing-xl);
  color: var(--gray-600);
}

.no-results {
  text-align: center;
  padding: var(--spacing-xl);
  background-color: white;
  border-radius: var(--border-radius-lg);
  box-shadow: var(--shadow-md);
}

.error-message {
  text-align: center;
  padding: var(--spacing-xl);
  background-color: #fff3f3;
  border-radius: var(--border-radius-lg);
  box-shadow: var(--shadow-md);
  border-left: 4px solid #dc3545;
}

/* ===== BACK TO TOP BUTTON ===== */
.back-to-top-btn {
  position: fixed;
  bottom: 30px;
  right: 30px;
  background-color: var(--primary-color);
  color: white;
  width: 50px;
  height: 50px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  cursor: pointer;
  box-shadow: var(--shadow-md);
  border: none;
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition-normal);
  z-index: 99;
}

.back-to-top-btn.show {
  opacity: 1;
  visibility: visible;
}

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

/* ===== FOOTER ===== */
footer {
  background-color: var(--gray-800);
  color: var(--gray-300);
  padding: var(--spacing-xl) 0;
  margin-top: var(--spacing-xl);
}

footer .container {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: var(--spacing-md);
}

.footer-links {
  display: flex;
  gap: var(--spacing-lg);
}

.footer-links a {
  color: var(--gray-300);
}

.footer-links a:hover {
  color: white;
}

/* ===== ACCESSIBILITY ===== */
:focus {
  outline: 3px solid var(--accent-color);
  outline-offset: 2px;
}

.keyboard-focus {
  outline: 3px solid var(--accent-color);
  outline-offset: 2px;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}

/* ===== ANIMATIONS ===== */
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}

.category-section {
  animation: fadeIn var(--transition-normal) forwards;
  opacity: 0;
}

/* Staggered animation for categories */
.category-section:nth-child(1) { animation-delay: 0.1s; }
.category-section:nth-child(2) { animation-delay: 0.2s; }
.category-section:nth-child(3) { animation-delay: 0.3s; }
.category-section:nth-child(4) { animation-delay: 0.4s; }
.category-section:nth-child(5) { animation-delay: 0.5s; }
.category-section:nth-child(6) { animation-delay: 0.6s; }
.category-section:nth-child(7) { animation-delay: 0.7s; }
.category-section:nth-child(8) { animation-delay: 0.8s; }
.category-section:nth-child(9) { animation-delay: 0.9s; }
.category-section:nth-child(10) { animation-delay: 1s; }
.category-section:nth-child(n+11) { animation-delay: 1.1s; }

/* ===== RESPONSIVE DESIGN ===== */
@media (max-width: 768px) {
  .filter-nav .container {
    flex-direction: column;
    align-items: stretch;
  }
  
  .search-container {
    max-width: 100%;
  }
  
  .tools-grid {
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  }
  
  footer .container {
    flex-direction: column;
    text-align: center;
  }
  
  .footer-links {
    justify-content: center;
  }
  
  .quick-filter-buttons {
    justify-content: center;
  }
}

@media (max-width: 480px) {
  html {
    font-size: 14px;
  }
  
  .tools-grid {
    grid-template-columns: 1fr;
  }
  
  header {
    padding: var(--spacing-lg) 0;
  }
  
  header h1 {
    font-size: 2rem;
  }
  
  .back-to-top-btn {
    width: 40px;
    height: 40px;
    right: 20px;
    bottom: 20px;
  }
}