body {
  margin: 0;
  font-family: Arial, sans-serif;
  background: #f8f9fa;
  color: #333;
}

.navbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 2rem;
  background: #1e3a8a;
  color: white;
}

.navbar ul {
  list-style: none;
  display: flex;
  gap: 1rem;
}

.navbar a {
  text-decoration: none;
  color: white;
  font-weight: bold;
}

.hero {
  text-align: center;
  padding: 3rem;
  background: #3b82f6;
  color: white;
}

.btn {
  display: inline-block;
  margin-top: 1rem;
  padding: 0.5rem 1rem;
  background: #1e3a8a;
  color: white;
  text-decoration: none;
  border-radius: 5px;
}

.courses, .course-detail, .profile {
  padding: 2rem;
}

.course-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 1.5rem;
}

.course-card {
  background: white;
  padding: 1rem;
  border-radius: 10px;
  box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

.progress {
  background: #e5e7eb;
  border-radius: 5px;
  overflow: hidden;
  margin: 0.5rem 0;
}

.progress-bar {
  height: 10px;
  background: #3b82f6;
}

.video-container {
  margin: 1rem 0;
}