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

body {
  font-family: 'Segoe UI', sans-serif;
  background: linear-gradient(135deg, #0b1220, #0f172a);
  color: white;
}

/* HEADER */

header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 20px 60px;
  background: rgba(15, 23, 42, 0.9);
  backdrop-filter: blur(10px);
  position: sticky;
  top: 0;
  z-index: 1000;
}

.logo {
  font-size: 22px;
  font-weight: bold;
  color: #22c55e;
}

nav {
  display: flex;
  gap: 25px;
}

nav a {
  text-decoration: none;
  color: #cbd5e1;
  padding: 8px 15px;
  border-radius: 20px;
  transition: 0.3s;
}

nav a:hover {
  color: white;
  background: #22c55e33;
}

nav a.active {
  background: #22c55e;
  color: white;
  box-shadow: 0 0 15px rgba(34,197,94,0.6);
}

/* SEKCJE */

.section {
  padding: 100px 60px;
  text-align: center;
}

.section h1,
.section h2 {
  margin-bottom: 20px;
}

.section p {
  color: #94a3b8;
  max-width: 700px;
  margin: 0 auto 40px auto;
}

/* KARTY */

.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 30px;
  margin-top: 50px;
}

.card {
  background: #111827;
  padding: 40px 30px;
  border-radius: 20px;
  border: 1px solid #1e293b;
  transition: 0.4s;
}

.card:hover {
  transform: translateY(-8px);
  border-color: #22c55e;
  box-shadow: 0 0 30px rgba(34,197,94,0.3);
}

.card h3 {
  color: #22c55e;
  margin-bottom: 15px;
}

.card p {
  color: #94a3b8;
}

footer {
  text-align: center;
  padding: 40px 20px;
  background: #0f172a;
  color: #64748b;
  margin-top: 80px;
}

/* RESPONSYWNOŚĆ */

@media (max-width: 768px) {
  header {
    flex-direction: column;
    gap: 15px;
    padding: 20px;
  }

  nav {
    flex-wrap: wrap;
    justify-content: center;
  }

  .section {
    padding: 60px 20px;
  }
}