:root {
  --primary: #1E3A8A;
  --accent: #10B981;
  --white: #FFFFFF;
  --light: #F9FAFB;
  --gray: #6B7280;
  --dark: #111827;
  --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  --radius: 0.75rem;
  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --ease-out: cubic-bezier(0, 0, 0.2, 1);
}

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

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  line-height: 1.6;
  color: var(--dark);
  background: var(--light);
  transition: background 0.5s var(--ease-out), color 0.5s var(--ease-out);
  overflow-x: hidden;
}

body[data-theme="dark"] {
  background: #0F172A;
  color: #E5E7EB;
}

/* === CONTAINER & GRID === */
.container {
  width: 100%;
  max-width: 1400px;
  margin: 0 auto;
  padding: 0 1rem;
}

.grid {
  display: grid;
  gap: 2rem;
}

.col-1 { grid-template-columns: repeat(1, 1fr); }
.col-2 { grid-template-columns: repeat(2, 1fr); }
.col-3 { grid-template-columns: repeat(3, 1fr); }
.col-4 { grid-template-columns: repeat(4, 1fr); }

@media (min-width: 640px) {
  .sm\\:col-2 { grid-template-columns: repeat(2, 1fr); }
}
@media (min-width: 768px) {
  .md\\:col-2 { grid-template-columns: repeat(2, 1fr); }
  .md\\:col-3 { grid-template-columns: repeat(3, 1fr); }
  .md\\:col-4 { grid-template-columns: repeat(4, 1fr); }
}
@media (min-width: 1024px) {
  .lg\\:col-3 { grid-template-columns: repeat(3, 1fr); }
  .lg\\:col-4 { grid-template-columns: repeat(4, 1fr); }
}

/* === TYPOGRAPHY === */
h1, h2, h3 { font-weight: 700; line-height: 1.2; }
h1 { font-size: clamp(2rem, 5vw, 3rem); }
h2 { font-size: clamp(1.75rem, 4vw, 2.5rem); }
h3 { font-size: 1.5rem; }

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

/* === BUTTONS === */
.btn {
  display: inline-block;
  padding: 0.75rem 1.5rem;
  border-radius: var(--radius);
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  transition: var(--transition);
  position: relative;
  overflow: hidden;
  z-index: 1;
}
.btn::before {
  content: '';
  position: absolute;
  top: 0; left: -100%;
  width: 100%; height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255,255,255,0.3), transparent);
  transition: 0.6s;
  z-index: -1;
}
.btn:hover::before { left: 100%; }

.btn-primary {
  background: var(--accent);
  color: white;
  box-shadow: 0 4px 14px rgba(16, 185, 129, 0.3);
}
.btn-primary:hover {
  background: #059669;
  transform: translateY(-2px);
  box-shadow: 0 8px 20px rgba(16, 185, 129, 0.4);
}

.btn-secondary {
  background: transparent;
  color: var(--accent);
  border: 2px solid var(--accent);
}
.btn-secondary:hover {
  background: var(--accent);
  color: white;
  transform: translateY(-2px);
}

/* === CARDS === */
.card {
  background: white;
  padding: 1.5rem;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  transition: var(--transition);
  opacity: 0;
  transform: translateY(30px);
}
.card.animate {
  opacity: 1;
  transform: translateY(0);
  transition: all 0.6s var(--ease-out);
}
.card:hover {
  transform: translateY(-8px);
  box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
}

body[data-theme="dark"] .card {
  background: #1E293B;
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.3);
}

/* === NAV === */
nav {
  position: sticky;
  top: 0;
  background: rgba(255,255,255,0.95);
  backdrop-filter: blur(12px);
  z-index: 1000;
  padding: 1rem 0;
  border-bottom: 1px solid #E5E7EB;
  transition: var(--transition);
}
body[data-theme="dark"] nav {
  background: rgba(15,23,42,0.95);
  border-color: #334155;
}

nav .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.logo { height: 40px; transition: var(--transition); }
.hamburger { display: none; font-weight: 600; cursor: pointer; color: var(--accent); }

.nav-links {
  display: flex;
  gap: 2rem;
  align-items: center;
}
.nav-links a {
  text-decoration: none;
  color: var(--dark);
  font-weight: 500;
  position: relative;
  transition: var(--transition);
}
.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--accent);
  transition: width 0.3s ease;
}
.nav-links a:hover::after { width: 100%; }
body[data-theme="dark"] .nav-links a { color: #E5E7EB; }

.theme-toggle {
  background: none;
  border: none;
  font-size: 0.9rem;
  cursor: pointer;
  color: var(--accent);
  transition: var(--transition);
}
.theme-toggle:hover { transform: scale(1.1); }

/* === HERO WITH PARALLAX === */
.hero {
  padding: 8rem 0 6rem;
  text-align: center;
  position: relative;
  overflow: hidden;
}
.hero::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0; bottom: 0;
  background: linear-gradient(135deg, rgba(16,185,129,0.1), transparent);
  transform: translateY(20px);
  transition: transform 0.8s ease;
  z-index: -1;
}
.hero h1 span {
  background: linear-gradient(90deg, var(--accent), #34D399);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* === CTA PULSE === */
.pulse {
  animation: pulse 2s infinite;
}
@keyframes pulse {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.05); }
}

/* === SECTIONS === */
section { padding: 5rem 0; position: relative; }
.section-title {
  text-align: center;
  margin-bottom: 3rem;
  opacity: 0;
  transform: translateY(20px);
  transition: all 0.8s var(--ease-out);
}
.section-title.animate {
  opacity: 1;
  transform: translateY(0);
}

/* === FOOTER === */
footer {
  background: var(--primary);
  color: white;
  text-align: center;
  padding: 2.5rem 0;
  position: relative;
}
footer::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 4px;
  background: linear-gradient(90deg, var(--accent), #34D399);
}

/* === DARK MODE === */
body[data-theme="dark"] .hero::before { background: rgba(16,185,129,0.2); }

/* === RESPONSIVE NAV === */
@media (max-width: 768px) {
  .hamburger { display: block; }
  .nav-links {
    position: absolute;
    top: 100%; left: 0; right: 0;
    background: white;
    flex-direction: column;
    padding: 1.5rem;
    border-top: 1px solid #E5E7EB;
    transform: translateY(-100%);
    opacity: 0;
    pointer-events: none;
    transition: var(--transition);
  }
  body[data-theme="dark"] .nav-links { background: #1E293B; }
  .nav-links.active {
    transform: translateY(0);
    opacity: 1;
    pointer-events: all;
  }
}

/* === SCROLL ANIMATIONS === */
.fade-in { opacity: 0; transform: translateY(30px); transition: all 0.8s var(--ease-out); }
.fade-in.visible { opacity: 1; transform: translateY(0); }

/* Staggered animation */
.stagger-1 { transition-delay: 0.1s; }
.stagger-2 { transition-delay: 0.2s; }
.stagger-3 { transition-delay: 0.3s; }
.stagger-4 { transition-delay: 0.4s; }