:root {
  --color-primary: #4f46e5;
  --color-primary-light: #818cf8;
  --color-primary-dark: #4338ca;
  --color-primary-bg: #eef2ff;
  --color-accent: #f59e0b;
  --color-gray-50: #f9fafb;
  --color-gray-100: #f3f4f6;
  --color-gray-200: #e5e7eb;
  --color-gray-300: #d1d5db;
  --color-gray-400: #9ca3af;
  --color-gray-500: #6b7280;
  --color-gray-600: #4b5563;
  --color-gray-700: #374151;
  --color-gray-800: #1f2937;
  --color-gray-900: #111827;
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.07), 0 2px 4px -1px rgba(0, 0, 0, 0.04);
  --shadow-lg: 0 10px 25px -3px rgba(0, 0, 0, 0.08), 0 4px 6px -2px rgba(0, 0, 0, 0.03);
  --shadow-xl: 0 20px 50px -8px rgba(79, 70, 229, 0.25);
  --radius-full: 9999px;
  --transition-smooth: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
  font-family: 'Inter', system-ui, -apple-system, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  background: #ffffff;
  color: var(--color-gray-800);
  line-height: 1.6;
}

.fade-section {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.8s cubic-bezier(0.2, 0.9, 0.3, 1),
    transform 0.8s cubic-bezier(0.2, 0.9, 0.3, 1);
  will-change: opacity, transform;
}

.fade-section.visible {
  opacity: 1;
  transform: translateY(0);
}

.fade-section .grid>* {
  transition-delay: 0.1s;
}

::-webkit-scrollbar {
  width: 8px;
  background: var(--color-gray-100);
}

::-webkit-scrollbar-thumb {
  background: var(--color-primary-light);
  border-radius: 20px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--color-primary);
}

header {
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(229, 231, 235, 0.5);
}

.hero-image-wrapper {
  background: linear-gradient(145deg, #eef2ff 0%, #f3e8ff 100%);
}

.btn-primary {
  background: var(--color-primary);
  color: white;
  padding: 0.75rem 2rem;
  border-radius: var(--radius-full);
  font-weight: 600;
  box-shadow: 0 10px 25px -5px rgba(79, 70, 229, 0.3);
  transition: var(--transition-smooth);
}

.btn-primary:hover {
  background: var(--color-primary-dark);
  box-shadow: 0 20px 40px -8px rgba(79, 70, 229, 0.4);
  transform: translateY(-2px);
}

.card-insight {
  background: white;
  border-radius: 1.5rem;
  padding: 2rem;
  border: 1px solid var(--color-gray-100);
  transition: var(--transition-smooth);
}

.card-insight:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-4px);
  border-color: var(--color-primary-light);
}

#backToTop {
  background: var(--color-primary);
  color: white;
  width: 52px;
  height: 52px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 12px 30px -6px rgba(79, 70, 229, 0.4);
  transition: var(--transition-smooth);
  border: none;
  cursor: pointer;
  opacity: 0;
  pointer-events: none;
  transform: scale(0.9);
}

#backToTop.visible {
  opacity: 1;
  pointer-events: auto;
  transform: scale(1);
}

#backToTop:hover {
  background: var(--color-primary-dark);
  transform: scale(1.06);
}

@media (max-width: 640px) {
  .fade-section {
    transform: translateY(18px);
  }

  .hero-image-wrapper {
    max-width: 280px;
    margin: 0 auto;
  }
}

.shadow-premium {
  box-shadow: 0 20px 60px -15px rgba(79, 70, 229, 0.15);
}

.gradient-text {
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}