/* CSS Custom Properties (Variables) */
:root {
  /* Light Theme Colors */
  --color-primary: #007AFF;
  --color-primary-dark: #0051D3;
  --color-secondary: #5856D6;
  --color-accent: #FF3B30;
  --color-success: #34C759;
  --color-warning: #FF9500;
  
  /* Background Colors */
  --color-bg-primary: #FFFFFF;
  --color-bg-secondary: #F2F2F7;
  --color-bg-tertiary: #FFFFFF;
  --color-bg-blur: rgba(255, 255, 255, 0.8);
  
  /* Text Colors */
  --color-text-primary: #000000;
  --color-text-secondary: #6D6D80;
  --color-text-tertiary: #8E8E93;
  --color-text-inverse: #FFFFFF;
  
  /* Border Colors */
  --color-border: #D1D1D6;
  --color-border-light: #E5E5EA;
  
  /* Shadow Colors */
  --shadow-light: rgba(0, 0, 0, 0.1);
  --shadow-medium: rgba(0, 0, 0, 0.15);
  --shadow-heavy: rgba(0, 0, 0, 0.25);
  
  /* Gradients */
  --gradient-primary: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
  --gradient-hero: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  
  /* Spacing */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;
  --spacing-3xl: 4rem;
  
  /* Border Radius */
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  
  /* Typography */
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 1.875rem;
  --font-size-4xl: 2.25rem;
  --font-size-5xl: 3rem;
  --font-size-6xl: 3.75rem;
  
  /* Font Weights */
  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;
  
  /* Line Heights */
  --line-height-tight: 1.25;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.75;
  
  /* Transitions */
  --transition-fast: 0.15s ease-out;
  --transition-normal: 0.3s ease-out;
  --transition-slow: 0.5s ease-out;
  
  /* Z-index */
  --z-navbar: 1000;
  --z-modal: 1100;
  --z-tooltip: 1200;
}

/* Dark Theme Colors */
[data-theme="dark"] {
  --color-bg-primary: #000000;
  --color-bg-secondary: #1C1C1E;
  --color-bg-tertiary: #2C2C2E;
  --color-bg-blur: rgba(0, 0, 0, 0.8);
  
  --color-text-primary: #FFFFFF;
  --color-text-secondary: #EBEBF5;
  --color-text-tertiary: #ABABAB;
  --color-text-inverse: #000000;
  
  --color-border: #38383A;
  --color-border-light: #2C2C2E;
  
  --shadow-light: rgba(0, 0, 0, 0.3);
  --shadow-medium: rgba(0, 0, 0, 0.4);
  --shadow-heavy: rgba(0, 0, 0, 0.6);
  
  --gradient-hero: linear-gradient(135deg, #1a1a2e 0%, #16213e 100%);
}

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

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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  font-size: var(--font-size-base);
  line-height: var(--line-height-normal);
  color: var(--color-text-primary);
  background-color: var(--color-bg-primary);
  transition: background-color var(--transition-normal), color var(--transition-normal);
  overflow-x: hidden;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
  font-weight: var(--font-weight-bold);
  line-height: var(--line-height-tight);
  margin-bottom: var(--spacing-md);
}

h1 {
  font-size: var(--font-size-5xl);
}

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

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(--spacing-md);
  color: var(--color-text-secondary);
}

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

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

/* Container */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}

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

/* Button Styles */
.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-medium);
  border: none;
  border-radius: var(--radius-lg);
  cursor: pointer;
  text-decoration: none;
  transition: all var(--transition-fast);
  position: relative;
  overflow: hidden;
}

.btn-primary {
  background: var(--gradient-primary);
  color: var(--color-text-inverse);
  box-shadow: 0 4px 16px var(--shadow-medium);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 32px var(--shadow-heavy);
  color: var(--color-text-inverse);
}

.btn-secondary {
  background: var(--color-bg-secondary);
  color: var(--color-text-primary);
  border: 1px solid var(--color-border);
}

.btn-secondary:hover {
  background: var(--color-bg-tertiary);
  transform: translateY(-2px);
  color: var(--color-text-primary);
}

/* Navigation */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: var(--z-navbar);
  background: var(--color-bg-blur);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--color-border-light);
  transition: all var(--transition-normal);
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--spacing-md) var(--spacing-lg);
  max-width: 1200px;
  margin: 0 auto;
}

.nav-brand .logo {
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-primary);
}

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

.nav-link {
  font-weight: var(--font-weight-medium);
  color: var(--color-text-primary);
  transition: color var(--transition-fast);
}

.nav-link:hover {
  color: var(--color-primary);
}

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

.theme-toggle {
  width: 40px;
  height: 40px;
  border: none;
  border-radius: var(--radius-md);
  background: var(--color-bg-secondary);
  color: var(--color-text-primary);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--font-size-lg);
  transition: all var(--transition-fast);
}

.theme-toggle:hover {
  background: var(--color-bg-tertiary);
  transform: scale(1.05);
}

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  width: 40px;
  height: 40px;
  border: none;
  background: transparent;
  cursor: pointer;
  padding: var(--spacing-sm);
}

.hamburger {
  width: 100%;
  height: 2px;
  background: var(--color-text-primary);
  transition: all var(--transition-fast);
  position: relative;
}

.hamburger::before,
.hamburger::after {
  content: '';
  position: absolute;
  width: 100%;
  height: 2px;
  background: var(--color-text-primary);
  transition: all var(--transition-fast);
}

.hamburger::before {
  top: -8px;
}

.hamburger::after {
  bottom: -8px;
}

/* Mobile Navigation */
@media (max-width: 768px) {
  .nav-container {
    padding: var(--spacing-md);
  }
  
  .nav-menu {
    position: fixed;
    top: 70px;
    left: 0;
    right: 0;
    background: var(--color-bg-blur);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    flex-direction: column;
    padding: var(--spacing-xl);
    gap: var(--spacing-lg);
    transform: translateY(-100vh);
    transition: transform var(--transition-normal);
    border-bottom: 1px solid var(--color-border-light);
  }
  
  .nav-menu.active {
    transform: translateY(0);
  }
  
  .nav-toggle {
    display: flex;
  }
  
  .nav-toggle.active .hamburger {
    background: transparent;
  }
  
  .nav-toggle.active .hamburger::before {
    transform: rotate(45deg);
    top: 0;
  }
  
  .nav-toggle.active .hamburger::after {
    transform: rotate(-45deg);
    bottom: 0;
  }
}

/* Sections */
section {
  padding: var(--spacing-3xl) 0;
  position: relative;
}

.section-header {
  text-align: center;
  margin-bottom: var(--spacing-3xl);
}

.section-title {
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: var(--spacing-md);
}

.section-description {
  font-size: var(--font-size-lg);
  max-width: 600px;
  margin: 0 auto;
}

/* Hero Section */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  background: var(--gradient-hero);
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><circle cx="20" cy="20" r="2" fill="rgba(255,255,255,0.1)"/><circle cx="80" cy="80" r="2" fill="rgba(255,255,255,0.1)"/><circle cx="40" cy="60" r="1" fill="rgba(255,255,255,0.05)"/></svg>');
  animation: float 20s infinite linear;
}

.hero-container {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--spacing-3xl);
  align-items: center;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
  position: relative;
  z-index: 1;
}

.hero-content {
  color: white;
}

.hero-title {
  margin-bottom: var(--spacing-xl);
}

.title-main {
  display: block;
  font-size: var(--font-size-6xl);
  font-weight: var(--font-weight-bold);
  line-height: var(--line-height-tight);
}

.title-sub {
  display: block;
  font-size: var(--font-size-5xl);
  font-weight: var(--font-weight-medium);
  opacity: 0.9;
}

.hero-description {
  font-size: var(--font-size-xl);
  line-height: var(--line-height-relaxed);
  margin-bottom: var(--spacing-2xl);
  opacity: 0.9;
  color: white;
}

.hero-actions {
  display: flex;
  gap: var(--spacing-lg);
  margin-bottom: var(--spacing-2xl);
}

/* Hero Visual */
.hero-visual {
  position: relative;
  height: 500px;
}

.hero-graphic {
  position: relative;
  width: 100%;
  height: 100%;
}

.floating-card {
  position: absolute;
  background: rgba(255, 255, 255, 0.1);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border: 1px solid rgba(255, 255, 255, 0.2);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  color: white;
  min-width: 120px;
  text-align: center;
  animation: float 6s ease-in-out infinite;
}

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

.floating-card .card-title {
  font-weight: var(--font-weight-medium);
  font-size: var(--font-size-sm);
}

.card-1 {
  top: 10%;
  left: 10%;
  animation-delay: 0s;
}

.card-2 {
  top: 20%;
  right: 20%;
  animation-delay: 1.5s;
}

.card-3 {
  bottom: 30%;
  left: 20%;
  animation-delay: 3s;
}

.card-4 {
  bottom: 20%;
  right: 10%;
  animation-delay: 4.5s;
}

/* Mobile Hero */
@media (max-width: 768px) {
  .hero-container {
    grid-template-columns: 1fr;
    text-align: center;
    padding: 0 var(--spacing-md);
  }
  
  .title-main {
    font-size: var(--font-size-4xl);
  }
  
  .title-sub {
    font-size: var(--font-size-3xl);
  }
  
  .hero-description {
    font-size: var(--font-size-lg);
  }
  
  .hero-actions {
    flex-direction: column;
    align-items: center;
  }
  
  .hero-visual {
    height: 300px;
  }
}

/* Animations */
@keyframes float {
  0%, 100% {
    transform: translateY(0px);
  }
  50% {
    transform: translateY(-20px);
  }
}

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Utility Classes */
.fade-in-up {
  animation: fadeInUp 0.6s ease-out;
}

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

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

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

.hidden {
  display: none;
}

.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;
}

/* Responsive adjustments */
@media (max-width: 480px) {
  :root {
    --spacing-md: 0.75rem;
    --spacing-lg: 1rem;
    --spacing-xl: 1.25rem;
    --spacing-2xl: 2rem;
    --spacing-3xl: 2.5rem;
  }
  
  .container {
    padding: 0 var(--spacing-md);
  }
  
  .btn {
    padding: var(--spacing-sm) var(--spacing-lg);
    font-size: var(--font-size-sm);
  }
}