/**
 * WebNav Hub - Main Stylesheet
 * Optimized for performance and maintainability
 */

/* ===== CSS Custom Properties ===== */
:root {
  /* Color Palette */
  --primary-color: #ff9000;
  --bg-color: #0d0d0d;
  --card-bg-color: #1a1a1a;
  --card-bg-hover: #2a2a2a;
  --text-color: #fff;
  --text-secondary: #ccc;
  
  /* Layout */
  --max-width: 1200px;
  --border-radius: 8px;
  --border-radius-large: 1.25rem;
  
  /* Spacing */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-xxl: 3rem;
  
  /* Typography */
  --font-system: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  --font-size-base: 16px;
  --font-size-sm: 0.875rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-xxl: 1.5rem;
  --font-size-xxxl: 2rem;
  --line-height-base: 1.6;
  
  /* Transitions & Animations */
  --transition-fast: all 0.15s ease;
  --transition-base: all 0.3s ease;
  --transition-slow: all 0.5s ease;
  --transform-transition: transform 0.2s ease;
  
  /* Shadows & Effects */
  --shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
  --shadow-hover: 0 8px 25px rgba(0, 0, 0, 0.3);
  
  /* Z-index Scale */
  --z-tooltip: 10;
  --z-overlay: 11;
  --z-modal: 12;
  --z-navigation: 1000;
}

/* ===== Base Styles ===== */
*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  font-size: var(--font-size-base);
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  -webkit-tap-highlight-color: transparent;
}

body {
  font-family: var(--font-system);
  margin: 0;
  padding: 0;
  background-color: var(--bg-color);
  color: var(--text-color);
  line-height: var(--line-height-base);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ===== Header Styles ===== */
header {
  background-color: #000;
  padding: var(--spacing-md);
  text-align: center;
  position: relative;
}

header h1 {
  font-size: var(--font-size-xxxl);
  font-weight: bold;
  color: var(--primary-color);
  margin: 0;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* Theme Toggle Button */
.theme-toggle {
  position: absolute;
  top: 50%;
  right: var(--spacing-md);
  transform: translateY(-50%);
  background: var(--card-bg-color);
  border: 2px solid var(--primary-color);
  border-radius: 50%;
  width: 3rem;
  height: 3rem;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: var(--transition-base);
  color: var(--primary-color);
}

.theme-toggle:hover,
.theme-toggle:focus {
  background-color: var(--primary-color);
  color: #000;
  transform: translateY(-50%) scale(1.1);
  outline: none;
}

.theme-toggle i {
  font-size: 1.2rem;
  transition: var(--transform-transition);
}

.theme-toggle:hover i,
.theme-toggle:focus i {
  transform: rotate(15deg);
}

/* ===== Navigation Styles ===== */
nav {
  background-color: var(--card-bg-color);
  padding: var(--spacing-sm);
  position: sticky;
  top: 0;
  z-index: var(--z-navigation);
}

nav ul {
  list-style-type: none;
  padding: 0;
  margin: 0;
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: var(--spacing-xs);
}

nav li {
  margin: var(--spacing-xs);
}

nav a {
  color: var(--text-color);
  text-decoration: none;
  font-size: var(--font-size-base);
  font-weight: 600;
  padding: var(--spacing-sm) calc(var(--spacing-sm) + 0.3rem);
  border-radius: var(--border-radius-large);
  transition: var(--transition-base);
  display: block;
}

nav a:hover,
nav a:focus,
nav a.active {
  background-color: var(--primary-color);
  color: #000;
  transform: translateY(-1px);
}

nav a:focus {
  outline: 2px solid var(--primary-color);
  outline-offset: 2px;
}

/* ===== Main Content Styles ===== */
main {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: var(--spacing-md);
}

/* ===== Section Styles ===== */
.category-section {
  margin-bottom: var(--spacing-xxl);
}

.category-title {
  font-size: var(--font-size-xxl);
  font-weight: bold;
  margin: var(--spacing-xl) 0 var(--spacing-md);
  color: var(--primary-color);
  border-left: 4px solid var(--primary-color);
  padding-left: calc(var(--spacing-sm) + 0.1rem);
  text-transform: uppercase;
  letter-spacing: 0.02em;
}

/* ===== Grid Layout ===== */
.link-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(8rem, 1fr));
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-xl);
}

/* ===== Card Styles ===== */
.link-card {
  background-color: var(--card-bg-color);
  border-radius: var(--border-radius);
  padding: 1.2rem 0.8rem;
  text-align: center;
  transition: var(--transition-base);
  cursor: pointer;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 90px;
  position: relative;
  overflow: hidden;
  will-change: transform;
  border: 1px solid transparent;
}

.link-card:hover,
.link-card:focus-within {
  background-color: var(--card-bg-hover);
  transform: translateY(-2px);
  box-shadow: var(--shadow-hover);
  border-color: var(--primary-color);
}

.link-card a {
  position: absolute;
  inset: 0;
  text-decoration: none;
  z-index: var(--z-overlay);
  display: block;
}

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

/* ===== Icon Styles ===== */
.link-card i {
  font-size: 1.8rem;
  margin-bottom: 0.7rem;
  color: var(--primary-color);
  transition: var(--transform-transition);
  position: relative;
  z-index: var(--z-tooltip);
  will-change: transform;
}

.link-card:hover i,
.link-card:focus-within i {
  transform: scale(1.1);
}

/* ===== Image Styles ===== */
.link-card img {
  width: 1.8rem;
  height: 1.8rem;
  margin-bottom: 0.7rem;
  object-fit: contain;
  transition: var(--transform-transition);
  position: relative;
  z-index: var(--z-tooltip);
  will-change: transform;
}

.link-card:hover img,
.link-card:focus-within img {
  transform: scale(1.1);
}

.link-card img[data-src] {
  opacity: 0;
  transition: opacity 0.3s ease;
}

.link-card img.loaded {
  opacity: 1;
}

/* ===== Text Styles ===== */
.link-card h3 {
  font-size: 0.9rem;
  margin: 0;
  color: var(--text-color);
  line-height: 1.3;
  font-weight: 500;
  max-width: 100%;
  height: 2.6em;
  overflow: hidden;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  line-clamp: 2;
  -webkit-box-orient: vertical;
  text-overflow: ellipsis;
  white-space: normal;
  padding: 0 0.3rem;
  position: relative;
  z-index: var(--z-tooltip);
}

/* ===== Footer Styles ===== */
footer {
  background-color: #000;
  color: var(--text-secondary);
  text-align: center;
  padding: var(--spacing-md);
  font-size: 0.75rem;
  margin-top: var(--spacing-xxl);
}

footer nav {
  margin-top: calc(var(--spacing-sm) + 0.1rem);
  background-color: transparent;
  position: static;
  padding: 0;
  display: flex;
  justify-content: center;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
}

footer nav a {
  color: var(--text-secondary);
  font-size: 0.75rem;
  padding: var(--spacing-xs);
  border-radius: var(--border-radius);
  white-space: nowrap;
}

footer nav a:hover,
footer nav a:focus {
  color: var(--primary-color);
  background-color: rgba(255, 144, 0, 0.1);
}

/* ===== Responsive Design ===== */

/* Large screens */
@media (max-width: 1200px) {
  main {
    padding: var(--spacing-md);
    max-width: 95%;
  }

  .link-grid {
    grid-template-columns: repeat(auto-fill, minmax(7.5rem, 1fr));
    gap: var(--spacing-md);
  }
}

/* Tablets */
@media (max-width: 768px) {
  html {
    font-size: 15px;
  }

  main {
    padding: 0.8rem;
  }

  .link-grid {
    grid-template-columns: repeat(auto-fill, minmax(7rem, 1fr));
    gap: 0.8rem;
  }

  nav {
    padding: 0.4rem;
  }

  nav a {
    padding: 0.4rem 0.7rem;
    font-size: 0.95rem;
  }

  .category-title {
    font-size: 1.4rem;
    margin: 1.8rem 0 var(--spacing-md);
  }

  .link-card {
    padding: var(--spacing-md) calc(var(--spacing-sm) + 0.1rem);
    min-height: 80px;
  }

  .link-card i,
  .link-card img {
    font-size: 1.6rem;
    width: 1.6rem;
    height: 1.6rem;
    margin-bottom: var(--spacing-sm);
  }

  .link-card h3 {
    font-size: 0.8rem;
    height: 2.4em;
  }

  /* Theme toggle adjustments for tablets */
  .theme-toggle {
    width: 2.5rem;
    height: 2.5rem;
    right: var(--spacing-sm);
  }

  .theme-toggle i {
    font-size: 1rem;
  }
}

/* Mobile phones */
@media (max-width: 480px) {
  html {
    font-size: 14px;
  }

  main {
    padding: calc(var(--spacing-sm) + 0.1rem);
  }

  .link-grid {
    grid-template-columns: repeat(auto-fill, minmax(6rem, 1fr));
    gap: 0.7rem;
  }

  header h1 {
    font-size: 1.6rem;
  }

  nav li {
    margin: var(--spacing-xs);
  }

  nav a {
    padding: 0.35rem calc(var(--spacing-sm) + 0.1rem);
    font-size: 0.9rem;
  }

  .category-title {
    font-size: 1.4rem;
    margin: 1.8rem 0 var(--spacing-md);
  }

  .link-card {
    padding: 0.8rem var(--spacing-sm);
    min-height: 70px;
  }

  .link-card i,
  .link-card img {
    font-size: 1.4rem;
    width: 1.4rem;
    height: 1.4rem;
    margin-bottom: 0.4rem;
  }

  .link-card h3 {
    font-size: 0.75rem;
    padding: 0 0.2rem;
    height: 2.4em;
  }

  footer {
    padding: 0.8rem;
  }

  footer nav a {
    font-size: 0.7rem;
    padding: calc(var(--spacing-xs) - 0.1rem);
  }

  /* Theme toggle adjustments for mobile */
  .theme-toggle {
    width: 2.2rem;
    height: 2.2rem;
    right: 0.8rem;
  }

  .theme-toggle i {
    font-size: 0.9rem;
  }
}

/* Small mobile phones */
@media (max-width: 360px) {
  html {
    font-size: 13px;
  }

  .link-grid {
    grid-template-columns: repeat(auto-fill, minmax(5.5rem, 1fr));
    gap: calc(var(--spacing-sm) + 0.1rem);
  }

  header h1 {
    font-size: 1.4rem;
  }

  .link-card {
    padding: 0.8rem var(--spacing-sm);
    min-height: 70px;
  }

  .link-card i,
  .link-card img {
    font-size: 1.3rem;
    width: 1.3rem;
    height: 1.3rem;
    margin-bottom: 0.3rem;
  }

  .link-card h3 {
    font-size: 0.7rem;
    padding: 0 0.15rem;
    height: 2.2em;
  }
}

/* ===== Utility Classes ===== */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.no-scroll {
  overflow: hidden;
}

/* ===== Print Styles ===== */
@media print {
  * {
    background: transparent !important;
    color: black !important;
    box-shadow: none !important;
    text-shadow: none !important;
  }

  body {
    font-size: 12pt;
    line-height: 1.4;
  }

  header,
  nav,
  footer {
    display: none;
  }

  .link-card {
    break-inside: avoid;
    border: 1px solid #ccc;
    padding: 0.5rem;
    margin-bottom: 0.5rem;
  }

  .link-card a::after {
    content: " (" attr(href) ")";
    font-size: 0.8em;
    color: #666;
  }
}

/* ===== Dark Mode Support (Default) ===== */
:root,
:root[data-theme="dark"] {
  /* Color Palette - Dark Theme */
  --primary-color: #ff9000;
  --bg-color: #0d0d0d;
  --card-bg-color: #1a1a1a;
  --card-bg-hover: #2a2a2a;
  --text-color: #fff;
  --text-secondary: #ccc;
}

/* Light Theme Override */
:root[data-theme="light"] {
  --bg-color: #ffffff;
  --card-bg-color: #f8f9fa;
  --card-bg-hover: #e9ecef;
  --text-color: #212529;
  --text-secondary: #6c757d;
}

:root[data-theme="light"] header,
:root[data-theme="light"] footer {
  background-color: #f8f9fa;
  border-bottom: 1px solid #dee2e6;
}

:root[data-theme="light"] nav {
  background-color: #ffffff;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

/* System Preference Based Theme (Optional) */
@media (prefers-color-scheme: light) {
  :root:not([data-theme]) {
    --bg-color: #0d0d0d;
    --card-bg-color: #1a1a1a;
    --card-bg-hover: #2a2a2a;
    --text-color: #fff;
    --text-secondary: #ccc;
  }
}

/* ===== Animation Classes ===== */
@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.fade-in {
  animation: fadeIn 0.6s ease-out;
}

/* ===== Focus Management ===== */
.skip-link {
  position: absolute;
  top: -40px;
  left: 6px;
  background: var(--primary-color);
  color: #000;
  padding: 8px;
  text-decoration: none;
  border-radius: 4px;
  z-index: 10000;
}

.skip-link:focus {
  top: 6px;
}

/* ===== Performance Optimizations ===== */
.link-card,
.link-card i,
.link-card img {
  transform: translateZ(0);
  backface-visibility: hidden;
  perspective: 1000px;
}