/* Base Styles */
:root {
  /* Color System */
  --color-html5: #e34c26;
  --color-html5-dark: #c13b20;
  --color-primary: var(--color-html5);
  --color-primary-dark: var(--color-html5-dark);
  --color-secondary: #4b5563;
  --color-secondary-light: #9ca3af;
  --color-accent: #3b82f6;
  --color-success: #10b981;
  --color-warning: #f59e0b;
  --color-error: #ef4444;
  --color-light: #f9fafb;
  --color-dark: #1f2937;
  --color-white: #ffffff;
  --color-black: #111827;
  
  /* Typography */
  --font-family: 'Inter', system-ui, -apple-system, sans-serif;
  --font-size-base: 16px;
  --line-height-body: 1.5;
  --line-height-heading: 1.2;
  
  /* Spacing */
  --space-1: 4px;
  --space-2: 8px;
  --space-3: 16px;
  --space-4: 24px;
  --space-5: 32px;
  --space-6: 48px;
  --space-7: 64px;
  --space-8: 96px;
  
  /* Borders */
  --border-radius-sm: 4px;
  --border-radius-md: 8px;
  --border-radius-lg: 16px;
  --border-width: 1px;
  
  /* Shadows */
  --shadow-sm: 0 1px 2px 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);
  
  /* Transitions */
  --transition-fast: 150ms;
  --transition-normal: 250ms;
  --transition-slow: 350ms;
}

/* Reset and Base Styles */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  font-size: var(--font-size-base);
  scroll-behavior: smooth;
  scroll-padding-top: 80px;
}

body {
  font-family: var(--font-family);
  line-height: var(--line-height-body);
  color: var(--color-dark);
  background-color: var(--color-light);
}

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

h1, h2, h3, h4, h5, h6 {
  line-height: var(--line-height-heading);
  margin-bottom: var(--space-3);
  font-weight: 600;
}

/* Layout */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-3);
}

section {
  margin-bottom: var(--space-6);
  scroll-margin-top: 80px;
}

/* Header Styles */
.site-header {
  background: linear-gradient(to right, var(--color-primary), #f97316);
  color: var(--color-white);
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow-md);
  padding: var(--space-3) 0;
}

.header-content {
  display: grid;
  grid-template-columns: auto 1fr auto;
  gap: var(--space-3);
  align-items: center;
  position: relative;
}

.back-button {
  position: absolute;
  top: 0;
  left: 0;
  display: flex;
  align-items: center;
  padding: var(--space-2);
  border-radius: var(--border-radius-sm);
  background-color: rgba(255, 255, 255, 0.2);
  transition: background-color var(--transition-fast) ease;
  font-size: 0.9rem;
  white-space: nowrap;
  z-index: 10;
}

.back-button:hover {
  background-color: rgba(255, 255, 255, 0.3);
}

.logo-container {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  justify-self: center;
  margin-left: var(--space-8);
}

.logo {
  background-color: var(--color-white);
  border-radius: var(--border-radius-md);
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.logo-text {
  font-weight: 700;
  color: var(--color-primary);
  font-size: 1.5rem;
  font-family: monospace;
}

.site-title h1 {
  font-size: 1.5rem;
  margin-bottom: 0;
}

.site-title p {
  font-size: 0.875rem;
  opacity: 0.9;
}

.search-container {
  position: relative;
  width: 100%;
  max-width: 300px;
  justify-self: end;
}

.search-icon {
  position: absolute;
  top: 50%;
  left: var(--space-2);
  transform: translateY(-50%);
  color: rgba(255, 255, 255, 0.7);
}

#search-input {
  width: 100%;
  padding: var(--space-2) var(--space-2) var(--space-2) var(--space-5);
  border-radius: var(--border-radius-md);
  border: 1px solid rgba(255, 255, 255, 0.3);
  background-color: rgba(255, 255, 255, 0.2);
  color: var(--color-white);
  font-size: 0.9rem;
}

#search-input::placeholder {
  color: rgba(255, 255, 255, 0.7);
}

#search-input:focus {
  outline: none;
  background-color: rgba(255, 255, 255, 0.3);
  border-color: rgba(255, 255, 255, 0.5);
}

/* Mobile Responsive Header */
@media (max-width: 768px) {
  .header-content {
    display: flex;
    flex-direction: column;
    gap: var(--space-3);
    align-items: center;
    position: relative;
    padding-top: var(--space-6);
  }

  .back-button {
    position: absolute;
    top: 0;
    left: 0;
    margin: 0;
    padding: var(--space-1) var(--space-2);
    font-size: 0.85rem;
  }

  .logo-container {
    margin-left: 0;
    justify-self: auto;
  }

  .search-container {
    width: 100%;
    max-width: none;
    justify-self: auto;
  }

  .site-title h1 {
    font-size: 1.25rem;
  }

  .site-title p {
    font-size: 0.8rem;
  }
}

@media (max-width: 480px) {
  .header-content {
    padding-top: var(--space-5);
  }

  .back-button {
    padding: var(--space-1);
    font-size: 0.8rem;
  }

  .logo-container {
    gap: var(--space-2);
  }

  .logo {
    width: 40px;
    height: 40px;
  }

  .logo-text {
    font-size: 1.25rem;
  }

  .site-title h1 {
    font-size: 1.1rem;
  }

  .site-title p {
    font-size: 0.75rem;
  }
}

/* Introduction Section */
.intro-section {
  margin-top: var(--space-5);
}

.intro-card {
  background-color: var(--color-white);
  border-radius: var(--border-radius-md);
  padding: var(--space-4);
  box-shadow: var(--shadow-md);
}

.intro-actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
  margin-top: var(--space-4);
}

.btn {
  display: inline-block;
  padding: var(--space-2) var(--space-4);
  border-radius: var(--border-radius-md);
  font-weight: 500;
  transition: all var(--transition-fast) ease;
}

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

.btn-primary:hover {
  background-color: var(--color-primary-dark);
}

.btn-secondary {
  background-color: var(--color-light);
  color: var(--color-dark);
  border: 1px solid var(--color-secondary-light);
}

.btn-secondary:hover {
  background-color: var(--color-secondary-light);
  color: var(--color-dark);
}

/* Section Titles */
.section-title {
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--color-dark);
  margin-bottom: var(--space-2);
  padding-bottom: var(--space-2);
  border-bottom: 2px solid var(--color-primary);
  display: inline-block;
}

.section-description {
  color: var(--color-secondary);
  margin-bottom: var(--space-4);
}

/* Categories Section */
.categories-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-4);
}

@media (min-width: 640px) {
  .categories-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 1024px) {
  .categories-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

.category-card {
  background-color: var(--color-white);
  border-radius: var(--border-radius-md);
  overflow: hidden;
  box-shadow: var(--shadow-md);
  transition: transform var(--transition-normal) ease, box-shadow var(--transition-normal) ease;
  height: 100%;
}

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

.category-header {
  background-color: var(--color-primary);
  color: var(--color-white);
  padding: var(--space-3);
}

.category-header h3 {
  margin: 0;
  font-size: 1.125rem;
}

.category-header p {
  margin: var(--space-1) 0 0;
  font-size: 0.875rem;
}

.category-body {
  padding: var(--space-3);
  text-align: center;
}

.tag-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.tag-item {
  margin-bottom: var(--space-2);
  width: 100%;
  text-align: center;
}

.tag-link {
  display: inline-block;
  padding: var(--space-2);
  border-radius: var(--border-radius-sm);
  transition: background-color var(--transition-fast) ease;
}

.tag-link:hover {
  background-color: rgba(0, 0, 0, 0.05);
}

.tag-name {
  font-family: monospace;
  color: var(--color-primary);
  font-weight: 600;
}

/* Alphabetical Section */
.alphabetical-container {
  background-color: var(--color-white);
  border-radius: var(--border-radius-md);
  padding: var(--space-3);
  box-shadow: var(--shadow-md);
  width: 100%;
}

.tag-list {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
  gap: var(--space-2);
  list-style: none;
  padding: 0;
}

.tag-element {
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: var(--color-light);
  border-radius: var(--border-radius-sm);
  padding: var(--space-1) var(--space-2);
  font-family: monospace;
  font-weight: 600;
  color: var(--color-secondary);
  transition: all var(--transition-fast) ease;
  text-align: center;
  min-height: 40px;
  text-decoration: none;
}

.tag-element:hover {
  background-color: var(--color-primary);
  color: var(--color-white);
  transform: translateY(-2px);
}

/* Footer */
.site-footer {
  background-color: var(--color-dark);
  color: var(--color-white);
  padding: var(--space-4) 0;
  margin-top: var(--space-6);
}

.footer-content {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

@media (min-width: 768px) {
  .footer-content {
    flex-direction: row;
    justify-content: space-between;
    align-items: center;
  }
}

.copyright p {
  font-size: 0.875rem;
  color: var(--color-secondary-light);
}

.footer-links {
  display: flex;
  gap: var(--space-4);
}

.footer-links a {
  color: var(--color-secondary-light);
  font-size: 0.875rem;
}

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

/* Animations */
.fade-in {
  opacity: 0;
  transform: translateY(20px);
  animation: fadeIn 0.6s ease-out forwards;
}

@keyframes fadeIn {
  0% {
    opacity: 0;
    transform: translateY(20px);
  }
  100% {
    opacity: 1;
    transform: translateY(0);
  }
}

.delay-100 {
  animation-delay: 100ms;
}

.delay-200 {
  animation-delay: 200ms;
}

.delay-300 {
  animation-delay: 300ms;
}

.delay-400 {
  animation-delay: 400ms;
}

/* No Results */
.no-results {
  padding: var(--space-4);
  text-align: center;
  color: var(--color-secondary);
}

/* Page Transition */
.page-transition {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: var(--color-primary);
  z-index: 9999;
  transform: translateY(100%);
  transition: transform 0.5s ease-in-out;
  pointer-events: none; /* Allow clicks through when not active */
}

.page-transition.active {
  transform: translateY(0);
  pointer-events: all; /* Block clicks when active */
}