:root {
  /* Color Palette - Vibrant & Modern */
  --primary: #6366f1;
  --primary-dark: #4f46e5;
  --primary-light: #818cf8;
  --secondary: #8b5cf6;
  --accent: #ec4899;
  --success: #10b981;
  --warning: #f59e0b;
  --danger: #ef4444;
  
  /* Neutral Colors */
  --bg-primary: #0f172a;
  --bg-secondary: #1e293b;
  --bg-tertiary: #334155;
  --text-primary: #f1f5f9;
  --text-secondary: #cbd5e1;
  --text-muted: #94a3b8;
  
  /* Glassmorphism */
  --glass-bg: rgba(30, 41, 59, 0.7);
  --glass-border: rgba(148, 163, 184, 0.1);
  
  /* 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);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
  --shadow-glow: 0 0 20px rgba(99, 102, 241, 0.3);
  
  /* Spacing */
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 1.5rem;
  --spacing-lg: 2rem;
  --spacing-xl: 3rem;
  
  /* Border Radius */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  
  /* Typography */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'Fira Code', 'Courier New', monospace;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: var(--font-sans);
  background: linear-gradient(135deg, #0f172a 0%, #1e293b 100%);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  overflow-x: hidden;
}

/* Animated Background */
body::before {
  content: '';
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: 
    radial-gradient(circle at 20% 50%, rgba(99, 102, 241, 0.1) 0%, transparent 50%),
    radial-gradient(circle at 80% 80%, rgba(139, 92, 246, 0.1) 0%, transparent 50%),
    radial-gradient(circle at 40% 20%, rgba(236, 72, 153, 0.1) 0%, transparent 50%);
  pointer-events: none;
  z-index: -1;
}

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

/* Header */
header {
  padding: var(--spacing-md) 0;
  backdrop-filter: blur(10px);
  background: var(--glass-bg);
  border-bottom: 1px solid var(--glass-border);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-size: 1.5rem;
  font-weight: 700;
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.nav-links {
  display: flex;
  gap: var(--spacing-md);
  list-style: none;
}

.nav-links a {
  color: var(--text-secondary);
  text-decoration: none;
  font-weight: 500;
  transition: color 0.3s ease;
}

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

/* Buttons */
.btn {
  padding: 0.75rem 1.5rem;
  border: none;
  border-radius: var(--radius-lg);
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
  transition: all 0.3s ease;
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  text-decoration: none;
}

.btn-primary {
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  color: white;
  box-shadow: var(--shadow-md);
}

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

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

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

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

.btn-outline:hover {
  background: var(--primary);
  color: white;
}

.btn-success {
  background: var(--success);
  color: white;
}

.btn-danger {
  background: var(--danger);
  color: white;
}

/* Cards */
.card {
  background: var(--glass-bg);
  backdrop-filter: blur(10px);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-xl);
  padding: var(--spacing-lg);
  box-shadow: var(--shadow-lg);
  transition: all 0.3s ease;
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-xl);
}

/* Input Fields */
.input-group {
  margin-bottom: var(--spacing-md);
}

.input-group label {
  display: block;
  margin-bottom: var(--spacing-xs);
  color: var(--text-secondary);
  font-weight: 500;
}

input[type="text"],
input[type="email"],
input[type="password"],
textarea {
  width: 100%;
  padding: 0.75rem 1rem;
  background: var(--bg-secondary);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: 1rem;
  transition: all 0.3s ease;
}

input:focus,
textarea:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

/* Utility Classes */
.text-center {
  text-align: center;
}

.mt-1 { margin-top: var(--spacing-xs); }
.mt-2 { margin-top: var(--spacing-sm); }
.mt-3 { margin-top: var(--spacing-md); }
.mt-4 { margin-top: var(--spacing-lg); }

.mb-1 { margin-bottom: var(--spacing-xs); }
.mb-2 { margin-bottom: var(--spacing-sm); }
.mb-3 { margin-bottom: var(--spacing-md); }
.mb-4 { margin-bottom: var(--spacing-lg); }

.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-1 { gap: var(--spacing-xs); }
.gap-2 { gap: var(--spacing-sm); }
.gap-3 { gap: var(--spacing-md); }

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

.text-sm {
  font-size: 0.875rem;
}

.text-lg {
  font-size: 1.125rem;
}

.text-xl {
  font-size: 1.25rem;
}

.text-2xl {
  font-size: 1.5rem;
}

.text-3xl {
  font-size: 1.875rem;
}

.font-bold {
  font-weight: 700;
}

.font-mono {
  font-family: var(--font-mono);
}

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

@keyframes pulse {
  0%, 100% {
    opacity: 1;
  }
  50% {
    opacity: 0.5;
  }
}

@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}

.fade-in {
  animation: fadeIn 0.5s ease-out;
}

.pulse {
  animation: pulse 2s cubic-bezier(0.4, 0, 0.6, 1) infinite;
}

.spinner {
  animation: spin 1s linear infinite;
}

/* Responsive */
@media (max-width: 768px) {
  .nav-links {
    gap: var(--spacing-sm);
  }
  
  .btn {
    padding: 0.625rem 1.25rem;
    font-size: 0.875rem;
  }
  
  .card {
    padding: var(--spacing-md);
  }
}

/* Loading Spinner */
.loading {
  display: inline-block;
  width: 20px;
  height: 20px;
  border: 3px solid rgba(255, 255, 255, 0.3);
  border-radius: 50%;
  border-top-color: white;
  animation: spin 1s linear infinite;
}

/* Toast Notifications */
.toast {
  position: fixed;
  bottom: var(--spacing-lg);
  right: var(--spacing-lg);
  background: var(--glass-bg);
  backdrop-filter: blur(10px);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  padding: var(--spacing-md);
  box-shadow: var(--shadow-xl);
  z-index: 1000;
  animation: fadeIn 0.3s ease-out;
}

.toast.success {
  border-left: 4px solid var(--success);
}

.toast.error {
  border-left: 4px solid var(--danger);
}

.toast.warning {
  border-left: 4px solid var(--warning);
}