/*
 * LumoAI - Ultra Premium AI Development Website
 * Luxury Tech Design System
 * © 2025 LumoAI
 */

/* ============================================
   CSS CUSTOM PROPERTIES (Design Tokens)
   ============================================ */
:root {
  /* Colors - Premium Tech Palette */
  --color-bg-primary: #0A0E27;
  --color-bg-secondary: #0F1535;
  --color-bg-tertiary: #1A1F3A;
  --color-bg-glass: rgba(255, 255, 255, 0.05);
  --color-bg-glass-hover: rgba(255, 255, 255, 0.08);

  --color-primary: #0066FF;
  --color-primary-dark: #0052CC;
  --color-primary-light: #3384FF;

  --color-secondary: #8B5CF6;
  --color-secondary-dark: #7C3AED;

  --color-accent: #00F0FF;
  --color-accent-glow: rgba(0, 240, 255, 0.3);

  --color-success: #10B981;
  --color-warning: #F59E0B;
  --color-error: #EF4444;

  --color-text-primary: #FFFFFF;
  --color-text-secondary: #A0AEC0;
  --color-text-tertiary: #718096;

  /* Gradients */
  --gradient-primary: linear-gradient(135deg, #0066FF 0%, #00F0FF 100%);
  --gradient-secondary: linear-gradient(135deg, #8B5CF6 0%, #EC4899 100%);
  --gradient-hero: linear-gradient(180deg, #0A0E27 0%, #1A1F3A 100%);
  --gradient-mesh: radial-gradient(at 0% 0%, rgba(0, 102, 255, 0.2) 0%, transparent 50%),
                   radial-gradient(at 100% 0%, rgba(139, 92, 246, 0.2) 0%, transparent 50%),
                   radial-gradient(at 100% 100%, rgba(0, 240, 255, 0.2) 0%, transparent 50%),
                   radial-gradient(at 0% 100%, rgba(236, 72, 153, 0.2) 0%, transparent 50%);

  /* Typography */
  --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-display: 'SF Pro Display', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'SF Mono', 'Menlo', 'Monaco', 'Courier New', monospace;

  --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-size-7xl: 4.5rem;      /* 72px */

  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;
  --font-weight-black: 900;

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

  /* Spacing */
  --spacing-xs: 0.5rem;    /* 8px */
  --spacing-sm: 0.75rem;   /* 12px */
  --spacing-md: 1rem;      /* 16px */
  --spacing-lg: 1.5rem;    /* 24px */
  --spacing-xl: 2rem;      /* 32px */
  --spacing-2xl: 3rem;     /* 48px */
  --spacing-3xl: 4rem;     /* 64px */
  --spacing-4xl: 6rem;     /* 96px */
  --spacing-5xl: 8rem;     /* 128px */

  /* Layout */
  --max-width-sm: 640px;
  --max-width-md: 768px;
  --max-width-lg: 1024px;
  --max-width-xl: 1280px;
  --max-width-2xl: 1536px;

  /* Borders */
  --border-radius-sm: 0.375rem;   /* 6px */
  --border-radius-md: 0.5rem;     /* 8px */
  --border-radius-lg: 0.75rem;    /* 12px */
  --border-radius-xl: 1rem;       /* 16px */
  --border-radius-2xl: 1.5rem;    /* 24px */
  --border-radius-full: 9999px;

  --border-width: 1px;
  --border-color: rgba(255, 255, 255, 0.1);
  --border-color-hover: rgba(255, 255, 255, 0.2);

  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.4);
  --shadow-2xl: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
  --shadow-glow: 0 0 30px rgba(0, 102, 255, 0.4);
  --shadow-glow-accent: 0 0 30px rgba(0, 240, 255, 0.4);

  /* Transitions */
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 300ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 500ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-smooth: 700ms cubic-bezier(0.4, 0, 0.2, 1);

  /* Z-Index Scale */
  --z-base: 1;
  --z-dropdown: 1000;
  --z-sticky: 1020;
  --z-fixed: 1030;
  --z-modal-backdrop: 1040;
  --z-modal: 1050;
  --z-popover: 1060;
  --z-tooltip: 1070;
}

/* ============================================
   GLOBAL 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;
  text-rendering: optimizeLegibility;
}

body {
  font-family: var(--font-primary);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-normal);
  line-height: var(--line-height-normal);
  color: var(--color-text-primary);
  background-color: var(--color-bg-primary);
  background-image: var(--gradient-mesh);
  background-attachment: fixed;
  overflow-x: hidden;
  min-height: 100vh;
  direction: ltr;
  text-align: left;
}

/* ============================================
   TYPOGRAPHY
   ============================================ */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-display);
  font-weight: var(--font-weight-bold);
  line-height: var(--line-height-tight);
  color: var(--color-text-primary);
  margin-bottom: var(--spacing-lg);
}

h1 {
  font-size: var(--font-size-6xl);
  font-weight: var(--font-weight-black);
  letter-spacing: -0.02em;
}

h2 {
  font-size: var(--font-size-5xl);
  font-weight: var(--font-weight-black);
  letter-spacing: -0.01em;
}

h3 {
  font-size: var(--font-size-4xl);
  font-weight: var(--font-weight-bold);
}

h4 {
  font-size: var(--font-size-3xl);
  font-weight: var(--font-weight-bold);
}

h5 {
  font-size: var(--font-size-2xl);
  font-weight: var(--font-weight-semibold);
}

h6 {
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-semibold);
}

p {
  margin-bottom: var(--spacing-md);
  color: var(--color-text-secondary);
  line-height: var(--line-height-relaxed);
}

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

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

strong, b {
  font-weight: var(--font-weight-semibold);
}

/* Gradient Text */
.text-gradient {
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.text-gradient-secondary {
  background: var(--gradient-secondary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* ============================================
   LAYOUT UTILITIES
   ============================================ */
.container {
  width: 100%;
  max-width: var(--max-width-2xl);
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--spacing-xl);
  padding-right: var(--spacing-xl);
}

.container-sm {
  max-width: var(--max-width-lg);
}

.section {
  padding: var(--spacing-5xl) 0;
  position: relative;
}

.section-sm {
  padding: var(--spacing-4xl) 0;
}

.section-lg {
  padding: 10rem 0;
}

/* ============================================
   NAVIGATION
   ============================================ */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: var(--z-sticky);
  background: rgba(10, 14, 39, 0.8);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: var(--border-width) solid var(--border-color);
  transition: all var(--transition-base);
}

.navbar.scrolled {
  background: rgba(10, 14, 39, 0.95);
  box-shadow: var(--shadow-lg);
}

.navbar-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--spacing-lg) var(--spacing-xl);
  max-width: var(--max-width-2xl);
  margin: 0 auto;
}

.navbar-logo {
  font-size: var(--font-size-2xl);
  font-weight: var(--font-weight-black);
  color: var(--color-text-primary);
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  transition: transform var(--transition-fast);
}

.navbar-logo:hover {
  transform: scale(1.05);
  color: var(--color-text-primary);
}

.navbar-menu {
  display: flex;
  align-items: center;
  gap: var(--spacing-2xl);
  list-style: none;
}

.navbar-link {
  color: var(--color-text-secondary);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-medium);
  padding: var(--spacing-sm) var(--spacing-md);
  border-radius: var(--border-radius-md);
  transition: all var(--transition-fast);
  position: relative;
}

.navbar-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%) scaleX(0);
  width: 80%;
  height: 2px;
  background: var(--gradient-primary);
  transition: transform var(--transition-base);
}

.navbar-link:hover {
  color: var(--color-text-primary);
  background: var(--color-bg-glass);
}

.navbar-link:hover::after {
  transform: translateX(-50%) scaleX(1);
}

.navbar-link.active {
  color: var(--color-text-primary);
  background: var(--color-bg-glass-hover);
}

.navbar-cta {
  margin-left: var(--spacing-lg);
}

/* Mobile Menu Toggle */
.mobile-menu-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: transparent;
  border: none;
  cursor: pointer;
  padding: var(--spacing-sm);
}

.mobile-menu-toggle span {
  width: 25px;
  height: 2px;
  background: var(--color-text-primary);
  transition: all var(--transition-fast);
  border-radius: 2px;
}

/* ============================================
   BUTTONS
   ============================================ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-md) var(--spacing-xl);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-semibold);
  line-height: 1;
  border-radius: var(--border-radius-lg);
  border: none;
  cursor: pointer;
  transition: all var(--transition-base);
  text-decoration: none;
  position: relative;
  overflow: hidden;
  white-space: nowrap;
}

.btn::before {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  width: 0;
  height: 0;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.2);
  transform: translate(-50%, -50%);
  transition: width var(--transition-smooth), height var(--transition-smooth);
}

.btn:hover::before {
  width: 300px;
  height: 300px;
}

.btn-primary {
  background: var(--gradient-primary);
  color: var(--color-text-primary);
  box-shadow: var(--shadow-glow);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 0 40px rgba(0, 102, 255, 0.6);
}

.btn-secondary {
  background: var(--color-bg-glass);
  color: var(--color-text-primary);
  border: var(--border-width) solid var(--border-color);
  backdrop-filter: blur(10px);
}

.btn-secondary:hover {
  background: var(--color-bg-glass-hover);
  border-color: var(--border-color-hover);
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

.btn-outline {
  background: transparent;
  color: var(--color-text-primary);
  border: 2px solid var(--color-primary);
}

.btn-outline:hover {
  background: var(--color-primary);
  color: var(--color-text-primary);
  box-shadow: var(--shadow-glow);
  transform: translateY(-2px);
}

.btn-lg {
  padding: var(--spacing-lg) var(--spacing-2xl);
  font-size: var(--font-size-lg);
}

.btn-sm {
  padding: var(--spacing-sm) var(--spacing-lg);
  font-size: var(--font-size-sm);
}

/* Icon Buttons */
.btn-icon {
  width: 48px;
  height: 48px;
  padding: 0;
  border-radius: var(--border-radius-full);
}

/* ============================================
   HERO SECTION
   ============================================ */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  overflow: hidden;
  background: var(--gradient-hero);
  padding-top: 80px; /* Account for navbar */
}

.hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: var(--gradient-mesh);
  opacity: 0.5;
  animation: meshMove 20s ease-in-out infinite;
}

.hero-content {
  position: relative;
  z-index: var(--z-base);
  text-align: center;
  max-width: 1000px;
  margin: 0 auto;
  padding: var(--spacing-2xl);
}

.hero-title {
  font-size: clamp(2.5rem, 7vw, 5rem);
  margin-bottom: var(--spacing-xl);
  opacity: 0;
  animation: fadeInUp 1s ease-out forwards;
}

.hero-subtitle {
  font-size: clamp(1.125rem, 2vw, 1.5rem);
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-3xl);
  opacity: 0;
  animation: fadeInUp 1s ease-out 0.2s forwards;
  line-height: var(--line-height-relaxed);
}

.hero-cta {
  display: flex;
  gap: var(--spacing-lg);
  justify-content: center;
  flex-wrap: wrap;
  opacity: 0;
  animation: fadeInUp 1s ease-out 0.4s forwards;
}

/* Hero Stats */
.hero-stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: var(--spacing-2xl);
  margin-top: var(--spacing-5xl);
  padding-top: var(--spacing-3xl);
  border-top: var(--border-width) solid var(--border-color);
  opacity: 0;
  animation: fadeInUp 1s ease-out 0.6s forwards;
}

.hero-stat {
  text-align: center;
}

.hero-stat-number {
  font-size: var(--font-size-5xl);
  font-weight: var(--font-weight-black);
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  display: block;
  margin-bottom: var(--spacing-xs);
}

.hero-stat-label {
  font-size: var(--font-size-sm);
  color: var(--color-text-tertiary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* ============================================
   CARDS & COMPONENTS
   ============================================ */
.card {
  background: var(--color-bg-glass);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border: var(--border-width) solid var(--border-color);
  border-radius: var(--border-radius-2xl);
  padding: var(--spacing-2xl);
  transition: all var(--transition-base);
  position: relative;
  overflow: hidden;
}

.card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg,
    transparent 0%,
    rgba(255, 255, 255, 0.1) 50%,
    transparent 100%);
}

.card:hover {
  transform: translateY(-8px);
  background: var(--color-bg-glass-hover);
  border-color: var(--border-color-hover);
  box-shadow: var(--shadow-2xl);
}

.card-hover-glow:hover {
  box-shadow: var(--shadow-glow);
}

/* Project Cards */
.project-card {
  height: 100%;
  display: flex;
  flex-direction: column;
  cursor: pointer;
}

.project-card-image {
  width: 100%;
  aspect-ratio: 16/9;
  border-radius: var(--border-radius-xl);
  overflow: hidden;
  margin-bottom: var(--spacing-lg);
  position: relative;
}

.project-card-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform var(--transition-smooth);
}

.project-card:hover .project-card-image img {
  transform: scale(1.1);
}

.project-card-image::after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: linear-gradient(180deg, transparent 0%, rgba(0, 0, 0, 0.6) 100%);
  opacity: 0;
  transition: opacity var(--transition-base);
}

.project-card:hover .project-card-image::after {
  opacity: 1;
}

.project-card-content {
  flex: 1;
  display: flex;
  flex-direction: column;
}

.project-card-title {
  font-size: var(--font-size-2xl);
  margin-bottom: var(--spacing-sm);
}

.project-card-description {
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-lg);
  flex: 1;
}

.project-card-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-lg);
}

.tag {
  display: inline-flex;
  align-items: center;
  padding: var(--spacing-xs) var(--spacing-md);
  background: var(--color-bg-secondary);
  border: var(--border-width) solid var(--border-color);
  border-radius: var(--border-radius-full);
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-medium);
  color: var(--color-text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.tag-primary {
  background: rgba(0, 102, 255, 0.1);
  border-color: var(--color-primary);
  color: var(--color-primary);
}

/* Service Cards */
.service-card {
  text-align: center;
  padding: var(--spacing-3xl);
}

.service-icon {
  width: 80px;
  height: 80px;
  margin: 0 auto var(--spacing-xl);
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--gradient-primary);
  border-radius: var(--border-radius-2xl);
  font-size: var(--font-size-4xl);
  box-shadow: var(--shadow-glow);
  transition: transform var(--transition-base);
}

.service-card:hover .service-icon {
  transform: scale(1.1) rotate(5deg);
}

.service-title {
  font-size: var(--font-size-2xl);
  margin-bottom: var(--spacing-md);
}

.service-description {
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-lg);
}

.service-benefits {
  list-style: none;
  text-align: left;
  margin-top: var(--spacing-lg);
}

.service-benefits li {
  padding: var(--spacing-sm) 0;
  color: var(--color-text-secondary);
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.service-benefits li::before {
  content: '✓';
  color: var(--color-success);
  font-weight: var(--font-weight-bold);
}

/* ============================================
   GRID LAYOUTS
   ============================================ */
.grid {
  display: grid;
  gap: var(--spacing-2xl);
}

.grid-2 {
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
}

.grid-3 {
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
}

.grid-4 {
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
}

/* ============================================
   SECTION HEADERS
   ============================================ */
.section-header {
  text-align: center;
  max-width: 800px;
  margin: 0 auto var(--spacing-5xl);
}

.section-title {
  font-size: var(--font-size-5xl);
  margin-bottom: var(--spacing-lg);
}

.section-subtitle {
  font-size: var(--font-size-xl);
  color: var(--color-text-secondary);
}

/* ============================================
   FORMS
   ============================================ */
.form-group {
  margin-bottom: var(--spacing-xl);
}

.form-label {
  display: block;
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-sm);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.form-input,
.form-textarea,
.form-select {
  width: 100%;
  padding: var(--spacing-md) var(--spacing-lg);
  background: var(--color-bg-glass);
  border: var(--border-width) solid var(--border-color);
  border-radius: var(--border-radius-lg);
  color: var(--color-text-primary);
  font-size: var(--font-size-base);
  font-family: var(--font-primary);
  transition: all var(--transition-base);
  backdrop-filter: blur(10px);
}

.form-input:focus,
.form-textarea:focus,
.form-select:focus {
  outline: none;
  border-color: var(--color-primary);
  background: var(--color-bg-glass-hover);
  box-shadow: 0 0 0 3px rgba(0, 102, 255, 0.1);
}

.form-textarea {
  min-height: 150px;
  resize: vertical;
}

.form-input::placeholder,
.form-textarea::placeholder {
  color: var(--color-text-tertiary);
}

/* ============================================
   FOOTER
   ============================================ */
.footer {
  background: var(--color-bg-secondary);
  border-top: var(--border-width) solid var(--border-color);
  padding: var(--spacing-5xl) 0 var(--spacing-xl);
  margin-top: var(--spacing-5xl);
}

.footer-content {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--spacing-3xl);
  margin-bottom: var(--spacing-3xl);
}

.footer-section h3 {
  font-size: var(--font-size-xl);
  margin-bottom: var(--spacing-lg);
}

.footer-links {
  list-style: none;
}

.footer-links li {
  margin-bottom: var(--spacing-sm);
}

.footer-links a {
  color: var(--color-text-secondary);
  transition: color var(--transition-fast);
}

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

.footer-bottom {
  padding-top: var(--spacing-xl);
  border-top: var(--border-width) solid var(--border-color);
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--spacing-md);
  color: var(--color-text-tertiary);
  font-size: var(--font-size-sm);
}

/* ============================================
   UTILITIES
   ============================================ */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.mt-xs { margin-top: var(--spacing-xs); }
.mt-sm { margin-top: var(--spacing-sm); }
.mt-md { margin-top: var(--spacing-md); }
.mt-lg { margin-top: var(--spacing-lg); }
.mt-xl { margin-top: var(--spacing-xl); }
.mt-2xl { margin-top: var(--spacing-2xl); }
.mt-3xl { margin-top: var(--spacing-3xl); }

.mb-xs { margin-bottom: var(--spacing-xs); }
.mb-sm { margin-bottom: var(--spacing-sm); }
.mb-md { margin-bottom: var(--spacing-md); }
.mb-lg { margin-bottom: var(--spacing-lg); }
.mb-xl { margin-bottom: var(--spacing-xl); }
.mb-2xl { margin-bottom: var(--spacing-2xl); }
.mb-3xl { margin-bottom: var(--spacing-3xl); }

.opacity-0 { opacity: 0; }
.opacity-50 { opacity: 0.5; }
.opacity-100 { opacity: 1; }

/* Back to Top Button */
.back-to-top {
  position: fixed;
  bottom: var(--spacing-xl);
  right: var(--spacing-xl);
  width: 50px;
  height: 50px;
  background: var(--gradient-primary);
  border-radius: var(--border-radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  z-index: var(--z-fixed);
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition-base);
  box-shadow: var(--shadow-glow);
}

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

.back-to-top:hover {
  transform: translateY(-5px);
  box-shadow: 0 0 40px rgba(0, 102, 255, 0.6);
}

/* Loading Animation */
.loading {
  display: inline-block;
  width: 20px;
  height: 20px;
  border: 3px solid rgba(255, 255, 255, 0.2);
  border-top-color: var(--color-text-primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

/* Preloader */
.preloader {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: var(--color-bg-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 9999;
  transition: opacity 0.5s ease, visibility 0.5s ease;
}

.preloader .spinner {
  width: 60px;
  height: 60px;
  border: 4px solid rgba(255, 255, 255, 0.1);
  border-top-color: var(--color-primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

.preloader.fade-out {
  opacity: 0;
  visibility: hidden;
}

/* ============================================
   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;
}

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

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