:root {
  --primary: #0f172a;
  --accent: #22d3ee;
  --gray: #64748b;
  --light: #f8fafc;
}

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

body {
  font-family: 'Segoe UI', system-ui, sans-serif;
  line-height: 1.6;
  color: #334155;
  background: var(--light);
}

.dark {
  --primary: #0f172a;
  --light: #1e2937;
  color: #e2e8f0;
  background: #0f172a;
}

header {
  background: var(--primary);
  color: white;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

nav {
  max-width: 1200px;
  margin: 0 auto;
  padding: 1rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-size: 1.8rem;
  font-weight: bold;
  color: var(--accent);
  text-decoration: none;
}

.nav-links a {
  color: white;
  text-decoration: none;
  margin-left: 2rem;
  font-weight: 500;
  transition: color 0.3s;
}

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

.hero {
  background: linear-gradient(rgba(15,23,42,0.85), rgba(15,23,42,0.85)), url('https://picsum.photos/id/1015/2000/1200') center/cover;
  color: white;
  text-align: center;
  padding: 180px 20px 120px;
}

.btn {
  display: inline-block;
  background: var(--accent);
  color: #0f172a;
  padding: 14px 32px;
  border-radius: 50px;
  font-weight: bold;
  text-decoration: none;
  margin-top: 20px;
  transition: all 0.3s;
}

.btn:hover {
  transform: translateY(-3px);
  box-shadow: 0 10px 25px rgba(34,211,238,0.4);
}

.section {
  padding: 80px 20px;
  max-width: 1200px;
  margin: 0 auto;
}

h1, h2 {
  color: var(--primary);
}

.dark h1, .dark h2 {
  color: white;
}

.card {
  background: white;
  border-radius: 12px;
  padding: 2rem;
  box-shadow: 0 4px 20px rgba(0,0,0,0.08);
  transition: transform 0.3s;
}

.dark .card {
  background: #1e2937;
}

.card:hover {
  transform: translateY(-10px);
}

footer {
  background: var(--primary);
  color: white;
  text-align: center;
  padding: 3rem 1rem;
}