/* ====== Reset & Base ====== */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: "Segoe UI", Roboto, sans-serif;
  line-height: 1.6;
  color: #222;
  background: #f9fafb;
}

/* ====== Navbar ====== */
header {
  background: #0f172a;
  color: white;
  padding: 1rem 2rem;
  position: sticky;
  top: 0;
  z-index: 1000;
}

.navbar ul {
  display: flex;
  justify-content: center;
  list-style: none;
  gap: 2rem;
}

.navbar a {
  color: #e2e8f0;
  text-decoration: none;
  font-weight: 500;
  transition: color 0.3s;
}

.navbar a:hover,
.navbar a.active {
  color: #38bdf8;
}

/* ====== Hero Section ====== */
.hero {
  text-align: center;
  padding: 5rem 2rem;
  background: linear-gradient(135deg, #0ea5e9, #0369a1);
  color: white;
}

.hero h1 {
  font-size: 2.5rem;
  margin-bottom: 1rem;
}

.hero p {
  font-size: 1.2rem;
  max-width: 700px;
  margin: 0 auto;
}

/* ====== Lessons Section ====== */
.lessons {
  max-width: 900px;
  margin: 3rem auto;
  padding: 0 1.5rem;
}

.lessons h2 {
  font-size: 1.8rem;
  margin-bottom: 1.5rem;
  text-align: center;
  color: #0f172a;
}

.lessons ul {
  list-style: none;
}

.lessons li {
  background: white;
  margin-bottom: 1rem;
  padding: 1.2rem;
  border-radius: 12px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
  transition: transform 0.2s;
}

.lessons li:hover {
  transform: translateY(-3px);
}

.lessons strong {
  color: #0369a1;
}

.strong2 {
  color: black;
  font: bold;
}

/* ====== Footer ====== */
footer {
  text-align: center;
  padding: 1.5rem;
  background: #0f172a;
  color: #e2e8f0;
  margin-top: 3rem;
}

/* ====== Responsive ====== */
@media (max-width: 768px) {
  .navbar ul {
    flex-direction: column;
    gap: 1rem;
  }

  .hero h1 {
    font-size: 2rem;
  }

  .hero p {
    font-size: 1rem;
  }
}