/* ============================================
   AI NEXUS HUB - MAIN DESIGN SYSTEM
   Modern, Professional, Accessible
   ============================================ */

/* ============================================
   CSS CUSTOM PROPERTIES (Design Tokens)
   ============================================ */
:root {
  /* Color Palette - Vibrant & Professional */
  --primary-hue: 260;
  --primary-sat: 85%;

  --color-primary-900: hsl(var(--primary-hue), var(--primary-sat), 15%);
  --color-primary-800: hsl(var(--primary-hue), var(--primary-sat), 25%);
  --color-primary-700: hsl(var(--primary-hue), var(--primary-sat), 35%);
  --color-primary-600: hsl(var(--primary-hue), var(--primary-sat), 45%);
  --color-primary-500: hsl(var(--primary-hue), var(--primary-sat), 55%);
  --color-primary-400: hsl(var(--primary-hue), var(--primary-sat), 65%);
  --color-primary-300: hsl(var(--primary-hue), var(--primary-sat), 75%);

  --color-accent-500: hsl(320, 85%, 55%);
  --color-accent-400: hsl(320, 85%, 65%);

  --color-success: hsl(142, 71%, 45%);
  --color-warning: hsl(38, 92%, 50%);
  --color-error: hsl(0, 84%, 60%);

  /* Neutral Colors */
  --color-neutral-50: hsl(240, 20%, 98%);
  --color-neutral-100: hsl(240, 15%, 95%);
  --color-neutral-200: hsl(240, 12%, 88%);
  --color-neutral-300: hsl(240, 10%, 75%);
  --color-neutral-400: hsl(240, 8%, 60%);
  --color-neutral-500: hsl(240, 6%, 45%);
  --color-neutral-600: hsl(240, 8%, 30%);
  --color-neutral-700: hsl(240, 10%, 20%);
  --color-neutral-800: hsl(240, 12%, 12%);
  --color-neutral-900: hsl(240, 15%, 8%);

  /* Gradients */
  --gradient-primary: linear-gradient(135deg, var(--color-primary-600) 0%, var(--color-accent-500) 100%);
  --gradient-hero: linear-gradient(135deg, var(--color-primary-700) 0%, var(--color-primary-500) 50%, var(--color-accent-500) 100%);
  --gradient-card: linear-gradient(145deg, rgba(255, 255, 255, 0.05) 0%, rgba(255, 255, 255, 0.02) 100%);

  /* Typography */
  --font-family-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-family-display: 'Inter', sans-serif;

  --font-size-xs: 0.75rem;
  /* 12px */
  --font-size-sm: 0.875rem;
  /* 14px */
  --font-size-base: 1rem;
  /* 16px */
  --font-size-lg: 1.125rem;
  /* 18px */
  --font-size-xl: 1.25rem;
  /* 20px */
  --font-size-2xl: 1.5rem;
  /* 24px */
  --font-size-3xl: 1.875rem;
  /* 30px */
  --font-size-4xl: 2.25rem;
  /* 36px */
  --font-size-5xl: 3rem;
  /* 48px */
  --font-size-6xl: 3.75rem;
  /* 60px */

  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;
  --font-weight-extrabold: 800;

  --line-height-tight: 1.2;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.75;

  /* Spacing Scale */
  --space-1: 0.25rem;
  /* 4px */
  --space-2: 0.5rem;
  /* 8px */
  --space-3: 0.75rem;
  /* 12px */
  --space-4: 1rem;
  /* 16px */
  --space-5: 1.25rem;
  /* 20px */
  --space-6: 1.5rem;
  /* 24px */
  --space-8: 2rem;
  /* 32px */
  --space-10: 2.5rem;
  /* 40px */
  --space-12: 3rem;
  /* 48px */
  --space-16: 4rem;
  /* 64px */
  --space-20: 5rem;
  /* 80px */
  --space-24: 6rem;
  /* 96px */

  /* Border Radius */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-2xl: 1.5rem;
  --radius-full: 9999px;

  /* Shadows */
  --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);
  --shadow-2xl: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
  --shadow-glow: 0 0 20px rgba(139, 92, 246, 0.3);

  /* Transitions */
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 350ms cubic-bezier(0.4, 0, 0.2, 1);

  /* Z-index Scale */
  --z-dropdown: 1000;
  --z-sticky: 1020;
  --z-fixed: 1030;
  --z-modal-backdrop: 1040;
  --z-modal: 1050;
  --z-popover: 1060;
  --z-tooltip: 1070;

  /* Layout */
  --container-max-width: 1280px;
  --header-height: 72px;
}

/* ============================================
   RESET & BASE STYLES
   ============================================ */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-family-primary);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-normal);
  line-height: var(--line-height-normal);
  color: var(--color-neutral-100);
  background-color: var(--color-neutral-900);
  background-image:
    radial-gradient(circle at 20% 20%, rgba(139, 92, 246, 0.1) 0%, transparent 50%),
    radial-gradient(circle at 80% 80%, rgba(236, 72, 153, 0.1) 0%, transparent 50%);
  background-attachment: fixed;
  min-height: 100vh;
  overflow-x: hidden;
}

/* ============================================
   TYPOGRAPHY
   ============================================ */
h1,
h2,
h3,
h4,
h5,
h6 {
  font-family: var(--font-family-display);
  font-weight: var(--font-weight-bold);
  line-height: var(--line-height-tight);
  color: var(--color-neutral-50);
  margin-bottom: var(--space-4);
}

h1 {
  font-size: var(--font-size-5xl);
  font-weight: var(--font-weight-extrabold);
  letter-spacing: -0.02em;
}

h2 {
  font-size: var(--font-size-4xl);
  font-weight: var(--font-weight-bold);
}

h3 {
  font-size: var(--font-size-3xl);
}

h4 {
  font-size: var(--font-size-2xl);
}

h5 {
  font-size: var(--font-size-xl);
}

h6 {
  font-size: var(--font-size-lg);
}

p {
  margin-bottom: var(--space-4);
  color: var(--color-neutral-200);
}

a {
  color: var(--color-primary-400);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--color-primary-300);
}

a:focus-visible {
  outline: 2px solid var(--color-primary-400);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

/* ============================================
   LAYOUT UTILITIES
   ============================================ */
.container {
  width: 100%;
  max-width: var(--container-max-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--space-6);
  padding-right: var(--space-6);
}

.section {
  padding-top: var(--space-16);
  padding-bottom: var(--space-16);
}

.section-lg {
  padding-top: var(--space-24);
  padding-bottom: var(--space-24);
}

/* Grid System */
.grid {
  display: grid;
  gap: var(--space-6);
}

.grid-cols-1 {
  grid-template-columns: repeat(1, 1fr);
}

.grid-cols-2 {
  grid-template-columns: repeat(2, 1fr);
}

.grid-cols-3 {
  grid-template-columns: repeat(3, 1fr);
}

.grid-cols-4 {
  grid-template-columns: repeat(4, 1fr);
}

/* Flexbox Utilities */
.flex {
  display: flex;
}

.flex-col {
  flex-direction: column;
}

.items-center {
  align-items: center;
}

.justify-center {
  justify-content: center;
}

.justify-between {
  justify-content: space-between;
}

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

.gap-3 {
  gap: var(--space-3);
}

.gap-4 {
  gap: var(--space-4);
}

.gap-6 {
  gap: var(--space-6);
}

.gap-8 {
  gap: var(--space-8);
}

/* ============================================
   RESPONSIVE DESIGN
   ============================================ */
@media (max-width: 1024px) {
  :root {
    --font-size-5xl: 2.5rem;
    --font-size-4xl: 2rem;
  }

  .grid-cols-4 {
    grid-template-columns: repeat(2, 1fr);
  }

  .grid-cols-3 {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  :root {
    --font-size-5xl: 2rem;
    --font-size-4xl: 1.75rem;
    --space-16: 3rem;
    --space-24: 4rem;
  }

  .container {
    padding-left: var(--space-4);
    padding-right: var(--space-4);
  }

  .grid-cols-2,
  .grid-cols-3,
  .grid-cols-4 {
    grid-template-columns: 1fr;
  }

  /* Mobile Navigation */
  .menu-toggle {
    display: block;
  }

  .nav-menu {
    position: fixed;
    top: var(--header-height);
    left: 0;
    right: 0;
    background: var(--color-neutral-900);
    padding: var(--space-6);
    flex-direction: column;
    gap: var(--space-4);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    transform: translateY(-100%);
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-base);
    z-index: var(--z-fixed);
    box-shadow: var(--shadow-xl);
  }

  .nav-menu.active {
    transform: translateY(0);
    opacity: 1;
    visibility: visible;
  }

  .nav-link {
    width: 100%;
    text-align: center;
    padding: var(--space-3);
  }

  /* Adjustments */
  .hero-title {
    font-size: var(--font-size-4xl);
  }

  .hero-subtitle {
    font-size: var(--font-size-lg);
  }

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

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

@media (max-width: 480px) {
  :root {
    --font-size-5xl: 1.75rem;
    --font-size-4xl: 1.5rem;
  }
}

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

.skip-to-content {
  position: absolute;
  top: -100%;
  left: 0;
  background: var(--color-primary-600);
  color: white;
  padding: var(--space-4);
  text-decoration: none;
  z-index: 9999;
}

.skip-to-content:focus {
  top: 0;
}

/* Focus visible for keyboard navigation */
*:focus-visible {
  outline: 2px solid var(--color-primary-400);
  outline-offset: 2px;
}

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

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes slideInFromLeft {
  from {
    opacity: 0;
    transform: translateX(-20px);
  }

  to {
    opacity: 1;
    transform: translateX(0);
  }
}

@keyframes pulse {

  0%,
  100% {
    opacity: 1;
  }

  50% {
    opacity: 0.5;
  }
}

@keyframes shimmer {
  0% {
    background-position: -1000px 0;
  }

  100% {
    background-position: 1000px 0;
  }
}

.animate-fade-in {
  animation: fadeIn var(--transition-base) ease-out;
}

.animate-slide-in {
  animation: slideInFromLeft var(--transition-base) ease-out;
}

/* ============================================
   UTILITY CLASSES
   ============================================ */
.text-center {
  text-align: center;
}

.text-left {
  text-align: left;
}

.text-right {
  text-align: right;
}

.font-bold {
  font-weight: var(--font-weight-bold);
}

.font-semibold {
  font-weight: var(--font-weight-semibold);
}

.font-medium {
  font-weight: var(--font-weight-medium);
}

.text-primary {
  color: var(--color-primary-400);
}

.text-accent {
  color: var(--color-accent-400);
}

.text-muted {
  color: var(--color-neutral-400);
}

.bg-gradient-primary {
  background: var(--gradient-primary);
}

.mb-2 {
  margin-bottom: var(--space-2);
}

.mb-4 {
  margin-bottom: var(--space-4);
}

.mb-6 {
  margin-bottom: var(--space-6);
}

.mb-8 {
  margin-bottom: var(--space-8);
}

.mt-2 {
  margin-top: var(--space-2);
}

.mt-4 {
  margin-top: var(--space-4);
}

.mt-6 {
  margin-top: var(--space-6);
}

.mt-8 {
  margin-top: var(--space-8);
}

.hidden {
  display: none;
}

.block {
  display: block;
}

.inline-block {
  display: inline-block;
}