body { 
    font-family: Arial, sans-serif; 
    margin: 0; 
    padding: 0; 
    background-color: #f4f4f4;
}
header { 
    background: #007bff; 
    color: #fff; 
    padding: 1rem 2rem; 
    display: flex; 
    justify-content: space-between; 
    align-items: center;
}
nav ul { 
    list-style: none; 
    display: flex; 
    gap: 1.5rem; 
    padding: 0; 
}
nav a { 
    color: #fff; 
    text-decoration: none; 
    font-weight: bold;
}
#courses { 
    padding: 2rem; 
    max-width: 1200px; 
    margin: auto; 
}
#course-list {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1.5rem;
}
.course-card { 
    background: #fff; 
    border: 1px solid #ddd; 
    padding: 1.5rem; 
    border-radius: 8px; 
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}
.course-card h3 {
    margin-top: 0;
    color: #333;
}