/* ==========================================
   Modern LearnEase Website - Main Styles
   ==========================================
   Author: LearnEase Team
   Version: 2.0
   Modern, Responsive, Accessible Design
   ========================================== */

/* CSS Custom Properties (Variables) */
:root {
  /* Primary Colors */
  --primary-color: #6366f1;
  --primary-dark: #4f46e5;
  --primary-light: #818cf8;
  --primary-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);

  /* Secondary Colors */
  --secondary-color: #f59e0b;
  --secondary-dark: #d97706;
  --secondary-light: #fbbf24;

  /* Accent Colors */
  --accent-color: #10b981;
  --accent-dark: #059669;
  --accent-light: #34d399;

  /* Neutral Colors */
  --white: #ffffff;
  --gray-50: #f9fafb;
  --gray-100: #f3f4f6;
  --gray-200: #e5e7eb;
  --gray-300: #d1d5db;
  --gray-400: #9ca3af;
  --gray-500: #6b7280;
  --gray-600: #4b5563;
  --gray-700: #374151;
  --gray-800: #1f2937;
  --gray-900: #111827;
  --black: #000000;

  /* Text Colors */
  --text-primary: var(--gray-900);
  --text-secondary: var(--gray-600);
  --text-muted: var(--gray-500);
  --text-inverse: var(--white);

  /* Background Colors */
  --bg-primary: var(--white);
  --bg-secondary: var(--gray-50);
  --bg-dark: var(--gray-900);
  --bg-glass: rgba(255, 255, 255, 0.1);

  /* Gradients */
  --gradient-primary: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-dark) 100%);
  --gradient-secondary: linear-gradient(135deg, var(--secondary-color) 0%, var(--secondary-dark) 100%);
  --gradient-accent: linear-gradient(135deg, var(--accent-color) 0%, var(--accent-dark) 100%);
  --gradient-text: linear-gradient(135deg, var(--primary-color), var(--secondary-color));

  /* Typography */
  --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-secondary: 'Poppins', sans-serif;
  --font-weight-light: 300;
  --font-weight-regular: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;
  --font-weight-extrabold: 800;

  /* Font Sizes */
  --text-xs: 0.75rem;
  --text-sm: 0.875rem;
  --text-base: 1rem;
  --text-lg: 1.125rem;
  --text-xl: 1.25rem;
  --text-2xl: 1.5rem;
  --text-3xl: 1.875rem;
  --text-4xl: 2.25rem;
  --text-5xl: 3rem;
  --text-6xl: 3.75rem;

  /* Line Heights */
  --leading-none: 1;
  --leading-tight: 1.25;
  --leading-snug: 1.375;
  --leading-normal: 1.5;
  --leading-relaxed: 1.625;
  --leading-loose: 2;

  /* Spacing */
  --spacing-1: 0.25rem;
  --spacing-2: 0.5rem;
  --spacing-3: 0.75rem;
  --spacing-4: 1rem;
  --spacing-5: 1.25rem;
  --spacing-6: 1.5rem;
  --spacing-8: 2rem;
  --spacing-10: 2.5rem;
  --spacing-12: 3rem;
  --spacing-16: 4rem;
  --spacing-20: 5rem;
  --spacing-24: 6rem;
  --spacing-32: 8rem;

  /* Border Radius */
  --radius-sm: 0.25rem;
  --radius-md: 0.375rem;
  --radius-lg: 0.5rem;
  --radius-xl: 0.75rem;
  --radius-2xl: 1rem;
  --radius-3xl: 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-inner: inset 0 2px 4px 0 rgba(0, 0, 0, 0.06);
  --shadow-glow: 0 0 20px rgba(99, 102, 241, 0.3);

  /* Transitions */
  --transition-fast: 0.15s ease-in-out;
  --transition-normal: 0.3s ease-in-out;
  --transition-slow: 0.5s ease-in-out;
  --transition-bounce: 0.6s cubic-bezier(0.68, -0.55, 0.265, 1.55);

  /* 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;
  --z-toast: 1080;

  /* Breakpoints */
  --breakpoint-sm: 640px;
  --breakpoint-md: 768px;
  --breakpoint-lg: 1024px;
  --breakpoint-xl: 1280px;
  --breakpoint-2xl: 1536px;

  /* Container Widths */
  --container-sm: 640px;
  --container-md: 768px;
  --container-lg: 1024px;
  --container-xl: 1280px;
  --container-2xl: 1536px;
}

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

html {
  font-size: 100%;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  -ms-text-size-adjust: 100%;
}

body {
  font-family: var(--font-primary);
  font-size: var(--text-base);
  font-weight: var(--font-weight-regular);
  line-height: var(--leading-normal);
  color: var(--text-primary);
  background-color: var(--bg-primary);
  overflow-x: hidden;
  transition: background-color var(--transition-normal), color var(--transition-normal);
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-secondary);
  font-weight: var(--font-weight-bold);
  line-height: var(--leading-tight);
  letter-spacing: -0.025em;
  margin-bottom: var(--spacing-4);
  color: var(--text-primary);
}

h1 {
  font-size: clamp(2.5rem, 5vw, 4rem);
  font-weight: var(--font-weight-extrabold);
  line-height: var(--leading-none);
  letter-spacing: -0.05em;
}

h2 {
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: var(--font-weight-bold);
}

h3 {
  font-size: clamp(1.5rem, 3vw, 2rem);
  font-weight: var(--font-weight-semibold);
}

h4 {
  font-size: var(--text-xl);
  font-weight: var(--font-weight-semibold);
}

h5 {
  font-size: var(--text-lg);
  font-weight: var(--font-weight-medium);
}

h6 {
  font-size: var(--text-base);
  font-weight: var(--font-weight-medium);
}

p {
  margin-bottom: var(--spacing-4);
  color: var(--text-secondary);
  line-height: var(--leading-relaxed);
}

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

a:hover, a:focus {
  color: var(--primary-dark);
  text-decoration: none;
}

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

/* Images */
img, svg {
  max-width: 100%;
  height: auto;
  display: block;
}

/* Lists */
ul, ol {
  list-style: none;
}

/* Buttons */
button {
  font-family: inherit;
  font-size: inherit;
  border: none;
  background: none;
  cursor: pointer;
  transition: all var(--transition-fast);
}

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

/* Form Elements */
input, textarea, select {
  font-family: inherit;
  font-size: inherit;
  border: none;
  background: none;
  outline: none;
}

/* Utility Classes */
.container {
  width: 100%;
  max-width: var(--container-xl);
  margin: 0 auto;
  padding: 0 var(--spacing-4);
}

@media (min-width: 640px) {
  .container {
    max-width: var(--container-sm);
    padding: 0 var(--spacing-6);
  }
}

@media (min-width: 768px) {
  .container {
    max-width: var(--container-md);
    padding: 0 var(--spacing-8);
  }
}

@media (min-width: 1024px) {
  .container {
    max-width: var(--container-lg);
  }
}

@media (min-width: 1280px) {
  .container {
    max-width: var(--container-xl);
  }
}

@media (min-width: 1536px) {
  .container {
    max-width: var(--container-2xl);
  }
}

.section-padding {
  padding: var(--spacing-20) 0;
}

@media (max-width: 768px) {
  .section-padding {
    padding: var(--spacing-16) 0;
  }
}

/* Text Utilities */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.font-light { font-weight: var(--font-weight-light); }
.font-regular { font-weight: var(--font-weight-regular); }
.font-medium { font-weight: var(--font-weight-medium); }
.font-semibold { font-weight: var(--font-weight-semibold); }
.font-bold { font-weight: var(--font-weight-bold); }

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

/* Display Utilities */
.block { display: block; }
.inline-block { display: inline-block; }
.flex { display: flex; }
.inline-flex { display: inline-flex; }
.grid { display: grid; }
.hidden { display: none; }

/* Flex Utilities */
.flex-col { flex-direction: column; }
.flex-row { flex-direction: row; }
.flex-wrap { flex-wrap: wrap; }
.flex-nowrap { flex-wrap: nowrap; }
.items-center { align-items: center; }
.items-start { align-items: flex-start; }
.items-end { align-items: flex-end; }
.justify-center { justify-content: center; }
.justify-between { justify-content: space-between; }
.justify-around { justify-content: space-around; }
.justify-start { justify-content: flex-start; }
.justify-end { justify-content: flex-end; }

/* Position Utilities */
.relative { position: relative; }
.absolute { position: absolute; }
.fixed { position: fixed; }
.sticky { position: sticky; }

/* Overflow Utilities */
.overflow-hidden { overflow: hidden; }
.overflow-visible { overflow: visible; }
.overflow-auto { overflow: auto; }

/* Loading Screen */
.loading-screen {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 9999;
  opacity: 1;
  visibility: visible;
  transition: opacity 0.5s ease, visibility 0.5s ease;
}

.loading-screen.hidden {
  opacity: 0;
  visibility: hidden;
}

.loading-content {
  text-align: center;
  color: var(--white);
}

.loading-logo {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-3);
  margin-bottom: var(--spacing-8);
  font-size: var(--text-3xl);
  font-weight: var(--font-weight-bold);
}

.loading-logo i {
  font-size: 3rem;
  animation: bounce 2s infinite;
}

.loading-spinner {
  width: 60px;
  height: 60px;
  border: 4px solid rgba(255, 255, 255, 0.3);
  border-top: 4px solid var(--white);
  border-radius: 50%;
  margin: 0 auto var(--spacing-4);
  animation: spin 1s linear infinite;
}

@keyframes bounce {
  0%, 20%, 50%, 80%, 100% {
    transform: translateY(0);
  }
  40% {
    transform: translateY(-10px);
  }
  60% {
    transform: translateY(-5px);
  }
}

@keyframes spin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

/* Navigation */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(15px);
  -webkit-backdrop-filter: blur(15px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
  z-index: var(--z-sticky);
  transition: all var(--transition-normal);
  padding: var(--spacing-4) 0;
}

.navbar.scrolled {
  background: rgba(255, 255, 255, 0.98);
  box-shadow: var(--shadow-lg);
  padding: var(--spacing-3) 0;
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: var(--container-xl);
  margin: 0 auto;
  padding: 0 var(--spacing-4);
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: var(--spacing-2);
  font-size: var(--text-xl);
  font-weight: var(--font-weight-bold);
  color: var(--text-primary);
  text-decoration: none;
}

.nav-logo i {
  font-size: var(--text-2xl);
  color: var(--primary-color);
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: var(--spacing-8);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: var(--spacing-6);
}

.nav-link {
  position: relative;
  font-weight: var(--font-weight-medium);
  color: var(--text-secondary);
  padding: var(--spacing-2) var(--spacing-3);
  border-radius: var(--radius-lg);
  transition: all var(--transition-fast);
}

.nav-link:hover,
.nav-link.active {
  color: var(--primary-color);
  background: rgba(99, 102, 241, 0.1);
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 0;
  height: 2px;
  background: var(--primary-color);
  transition: width var(--transition-fast);
}

.nav-link:hover::after,
.nav-link.active::after {
  width: 80%;
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: var(--spacing-4);
}

.theme-toggle {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-full);
  background: var(--gray-100);
  color: var(--text-secondary);
  border: none;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.theme-toggle:hover {
  background: var(--primary-color);
  color: var(--white);
  transform: scale(1.1);
}

.cta-btn {
  display: flex;
  align-items: center;
  gap: var(--spacing-2);
  background: var(--gradient-primary);
  color: var(--white);
  padding: var(--spacing-3) var(--spacing-5);
  border-radius: var(--radius-full);
  font-weight: var(--font-weight-medium);
  transition: all var(--transition-fast);
  border: none;
  cursor: pointer;
}

.cta-btn:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

.cta-btn i {
  transition: transform var(--transition-fast);
}

.cta-btn:hover i {
  transform: translateX(4px);
}

/* Mobile Navigation */
.nav-toggle {
  display: none;
  flex-direction: column;
  cursor: pointer;
  padding: var(--spacing-2);
}

.nav-toggle .bar {
  width: 25px;
  height: 3px;
  background: var(--text-primary);
  margin: 3px 0;
  transition: all var(--transition-fast);
  border-radius: 2px;
}

.nav-toggle.active .bar:nth-child(1) {
  transform: rotate(-45deg) translate(-6px, 6px);
}

.nav-toggle.active .bar:nth-child(2) {
  opacity: 0;
}

.nav-toggle.active .bar:nth-child(3) {
  transform: rotate(45deg) translate(-6px, -6px);
}

@media (max-width: 1024px) {
  .nav-toggle {
    display: flex;
  }

  .nav-menu {
    position: fixed;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--bg-primary);
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: var(--spacing-8);
    border-top: 1px solid var(--gray-200);
    box-shadow: var(--shadow-xl);
    transform: translateY(-100%);
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-normal);
  }

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

  .nav-links {
    flex-direction: column;
    gap: var(--spacing-4);
    margin-bottom: var(--spacing-6);
  }

  .nav-link {
    text-align: center;
    padding: var(--spacing-4);
    border-radius: var(--radius-lg);
  }

  .nav-actions {
    justify-content: center;
    border-top: 1px solid var(--gray-200);
    padding-top: var(--spacing-6);
  }
}

/* Hero Section */
.hero-section {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding: var(--spacing-20) 0;
  overflow: hidden;
}

.hero-background {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: linear-gradient(135deg, 
    rgba(99, 102, 241, 0.05) 0%, 
    rgba(245, 158, 11, 0.05) 50%,
    rgba(16, 185, 129, 0.05) 100%);
  z-index: -2;
}

.hero-shapes {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: -1;
}

.shape {
  position: absolute;
  border-radius: var(--radius-full);
  background: linear-gradient(135deg, 
    rgba(99, 102, 241, 0.1), 
    rgba(245, 158, 11, 0.1));
  animation: float 20s infinite linear;
}

.shape-1 {
  width: 300px;
  height: 300px;
  top: 10%;
  left: -5%;
  animation-delay: 0s;
}

.shape-2 {
  width: 200px;
  height: 200px;
  top: 60%;
  right: -5%;
  animation-delay: -5s;
}

.shape-3 {
  width: 150px;
  height: 150px;
  bottom: 20%;
  left: 10%;
  animation-delay: -10s;
}

.shape-4 {
  width: 100px;
  height: 100px;
  top: 30%;
  right: 20%;
  animation-delay: -15s;
}

@keyframes float {
  0%, 100% {
    transform: translateY(0) rotate(0deg);
  }
  25% {
    transform: translateY(-20px) rotate(90deg);
  }
  50% {
    transform: translateY(-10px) rotate(180deg);
  }
  75% {
    transform: translateY(-30px) rotate(270deg);
  }
}

.hero-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--spacing-12);
  align-items: center;
}

@media (max-width: 1024px) {
  .hero-content {
    grid-template-columns: 1fr;
    gap: var(--spacing-8);
    text-align: center;
  }
}

.hero-text {
  max-width: 600px;
}

.hero-title {
  margin-bottom: var(--spacing-6);
  line-height: 1.1;
}

.hero-description {
  font-size: var(--text-lg);
  color: var(--text-secondary);
  margin-bottom: var(--spacing-8);
  line-height: var(--leading-relaxed);
}

.hero-stats {
  display: flex;
  gap: var(--spacing-6);
  margin-bottom: var(--spacing-8);
}

@media (max-width: 640px) {
  .hero-stats {
    flex-direction: column;
    gap: var(--spacing-4);
  }
}

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

.stat-number {
  display: block;
  font-size: var(--text-3xl);
  font-weight: var(--font-weight-bold);
  color: var(--primary-color);
  margin-bottom: var(--spacing-1);
}

.stat-label {
  font-size: var(--text-sm);
  color: var(--text-muted);
  font-weight: var(--font-weight-medium);
}

.hero-actions {
  display: flex;
  gap: var(--spacing-4);
  align-items: center;
}

@media (max-width: 640px) {
  .hero-actions {
    flex-direction: column;
    align-items: stretch;
  }
}

.primary-btn,
.secondary-btn {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-2);
  padding: var(--spacing-4) var(--spacing-6);
  border-radius: var(--radius-full);
  font-weight: var(--font-weight-medium);
  text-decoration: none;
  transition: all var(--transition-fast);
  border: none;
  cursor: pointer;
  font-size: var(--text-base);
}

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

.primary-btn:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-xl);
}

.secondary-btn {
  background: transparent;
  color: var(--text-primary);
  border: 2px solid var(--gray-300);
}

.secondary-btn:hover {
  border-color: var(--primary-color);
  color: var(--primary-color);
  transform: translateY(-2px);
}

.hero-visual {
  display: flex;
  justify-content: center;
  align-items: center;
}

.hero-card {
  background: var(--white);
  border-radius: var(--radius-2xl);
  padding: var(--spacing-6);
  box-shadow: var(--shadow-2xl);
  border: 1px solid var(--gray-200);
  max-width: 400px;
  width: 100%;
}

.course-preview {
  width: 100%;
}

.course-header {
  display: flex;
  align-items: center;
  gap: var(--spacing-3);
  margin-bottom: var(--spacing-4);
}

.course-avatar {
  width: 60px;
  height: 60px;
  border-radius: var(--radius-full);
  overflow: hidden;
  flex-shrink: 0;
}

.course-avatar img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.course-info h4 {
  font-size: var(--text-lg);
  font-weight: var(--font-weight-semibold);
  margin-bottom: var(--spacing-1);
}

.course-info p {
  color: var(--text-muted);
  font-size: var(--text-sm);
  margin: 0;
}

.course-rating {
  display: flex;
  align-items: center;
  gap: var(--spacing-1);
  color: var(--secondary-color);
}

.progress-bar {
  width: 100%;
  height: 8px;
  background: var(--gray-200);
  border-radius: var(--radius-full);
  overflow: hidden;
  margin-bottom: var(--spacing-2);
}

.progress-fill {
  height: 100%;
  background: var(--gradient-primary);
  border-radius: var(--radius-full);
  transition: width 2s ease-in-out;
}

.progress-text {
  font-size: var(--text-sm);
  color: var(--text-muted);
  margin: 0;
}

.floating {
  animation: floating 6s ease-in-out infinite;
}

@keyframes floating {
  0%, 100% {
    transform: translateY(0);
  }
  50% {
    transform: translateY(-20px);
  }
}

/* Scroll Indicator */
.scroll-indicator {
  position: absolute;
  bottom: var(--spacing-8);
  left: 50%;
  transform: translateX(-50%);
  text-align: center;
  color: var(--text-muted);
}

.scroll-mouse {
  width: 24px;
  height: 40px;
  border: 2px solid var(--text-muted);
  border-radius: 20px;
  margin: 0 auto var(--spacing-2);
  position: relative;
}

.scroll-wheel {
  width: 4px;
  height: 8px;
  background: var(--text-muted);
  border-radius: 2px;
  position: absolute;
  top: 6px;
  left: 50%;
  transform: translateX(-50%);
  animation: scroll 2s infinite;
}

@keyframes scroll {
  0%, 100% {
    opacity: 1;
    transform: translateX(-50%) translateY(0);
  }
  50% {
    opacity: 0.5;
    transform: translateX(-50%) translateY(12px);
  }
}

/* Section Headers */
.section-header {
  text-align: center;
  max-width: 800px;
  margin: 0 auto var(--spacing-12);
}

.section-subtitle {
  display: inline-block;
  background: var(--gradient-primary);
  color: var(--white);
  padding: var(--spacing-2) var(--spacing-4);
  border-radius: var(--radius-full);
  font-size: var(--text-sm);
  font-weight: var(--font-weight-medium);
  margin-bottom: var(--spacing-4);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.section-title {
  margin-bottom: var(--spacing-4);
}

.section-description {
  font-size: var(--text-lg);
  color: var(--text-secondary);
  line-height: var(--leading-relaxed);
}

/* Back to Top Button */
.back-to-top {
  position: fixed;
  bottom: var(--spacing-8);
  right: var(--spacing-8);
  width: 60px;
  height: 60px;
  background: var(--gradient-primary);
  color: var(--white);
  border: none;
  border-radius: var(--radius-full);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-xl);
  opacity: 0;
  visibility: hidden;
  transform: translateY(20px);
  transition: all var(--transition-normal);
  z-index: var(--z-fixed);
}

.back-to-top.show {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-to-top:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-2xl);
}

.progress-ring {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  transform: rotate(-90deg);
}

.progress-ring circle {
  transition: stroke-dashoffset 0.3s;
}

/* Responsive Design */
@media (max-width: 1200px) {
  :root {
    --spacing-32: 6rem;
    --spacing-24: 4rem;
    --spacing-20: 3.5rem;
  }
}

@media (max-width: 768px) {
  :root {
    --text-5xl: 2.5rem;
    --text-4xl: 2rem;
    --text-3xl: 1.5rem;
  }

  .section-padding {
    padding: var(--spacing-12) 0;
  }

  .hero-section {
    min-height: auto;
    padding: var(--spacing-24) 0 var(--spacing-16);
  }

  .container {
    padding: 0 var(--spacing-4);
  }
}

@media (max-width: 640px) {
  .hero-stats {
    justify-content: center;
  }

  .stat-item {
    min-width: 80px;
  }

  .back-to-top {
    width: 50px;
    height: 50px;
    bottom: var(--spacing-4);
    right: var(--spacing-4);
  }
}

/* Print Styles */
@media print {
  .navbar,
  .back-to-top,
  .loading-screen {
    display: none !important;
  }

  body {
    background: white !important;
    color: black !important;
  }

  .section-padding {
    padding: 1rem 0;
  }
}

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

  .scroll-behavior-smooth {
    scroll-behavior: auto;
  }
}

/* High Contrast Mode */
@media (prefers-contrast: high) {
  :root {
    --primary-color: #0000ff;
    --text-primary: #000000;
    --text-secondary: #333333;
    --bg-primary: #ffffff;
    --border-color: #000000;
  }

  .gradient-text {
    background: none;
    -webkit-background-clip: unset;
    -webkit-text-fill-color: unset;
    color: var(--primary-color);
  }
}