/* ==================== GLOBAL STYLES ==================== */
        /* Reset default browser margins and paddings */
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }
        
        /* Body styling - sets default font and background */
        body {
            font-family: Arial, sans-serif;
            line-height: 1.6;
            color: #333;
            background-color: #f4f4f4;
        }
        
        /* ==================== MOBILE-FIRST BASE STYLES ==================== */
        /* These styles apply to mobile devices first (smallest screens) */
        /* ==================== MOBILE-FIRST BASE STYLES ==================== */
        /* These styles apply to mobile devices first (smallest screens) */
        
        /* ==================== HEADER SECTION (MOBILE) ==================== */
        /* Header contains logo and navigation menu */
        header {
            background-color: #2563eb;
            color: white;
            padding: 1rem 0;
            box-shadow: 0 2px 5px rgba(0,0,0,0.1);
            position: relative;
        }
        
        /* Container to center content and add padding */
        .container {
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 20px;
        }
        
        /* Navigation bar layout - stacked on mobile */
        nav {
            display: flex;
            justify-content: space-between;
            align-items: center;
            flex-wrap: wrap;
        }
        
        /* Logo styling */
        .logo {
            font-size: 1.5rem;
            font-weight: bold;
        }
        
        /* Hamburger Menu Button - Only visible on mobile */
        .hamburger {
            display: block;
            background: none;
            border: none;
            cursor: pointer;
            padding: 5px;
        }
        
        /* Hamburger icon - three horizontal lines */
        .hamburger span {
            display: block;
            width: 25px;
            height: 3px;
            background-color: white;
            margin: 5px 0;
            transition: 0.3s;
        }
        
        /* Navigation menu - hidden by default on mobile, shown when active */
        nav ul {
            list-style: none;
            display: none; /* Hidden by default on mobile */
            flex-direction: column;
            width: 100%;
            text-align: center;
            padding: 1rem 0;
        }
        
        /* Show navigation when 'active' class is added via JavaScript */
        nav ul.active {
            display: flex;
        }
        
        /* Navigation list items - full width on mobile */
        nav ul li {
            width: 100%;
            padding: 0.5rem 0;
        }
        
        /* Navigation links styling */
        nav a {
            color: white;
            text-decoration: none;
            font-weight: 500;
            display: block;
            padding: 0.5rem;
            transition: background-color 0.3s;
        }
        
        /* Hover effect for navigation links */
        nav a:hover {
            background-color: rgba(255, 255, 255, 0.1);
        }
        
        /* Active page indicator */
        nav a.active {
            border-bottom: 2px solid white;
            padding-bottom: 5px;
        }
        
        /* ==================== HERO SECTION (MOBILE) ==================== */
        /* Large banner section at top of homepage */
        .hero {
            background: linear-gradient(135deg, #2563eb 0%, #1e40af 100%);
            color: white;
            padding: 2rem 0;
            text-align: center;
        }
        
        .hero h1 {
            font-size: 1.8rem;
            margin-bottom: 1rem;
        }
        
        .hero p {
            font-size: 1rem;
            margin-bottom: 1.5rem;
        }
        
        /* Call-to-action button styling */
        .cta-button {
            display: inline-block;
            background-color: white;
            color: #2563eb;
            padding: 12px 30px;
            text-decoration: none;
            border-radius: 5px;
            font-weight: bold;
            transition: transform 0.3s, box-shadow 0.3s;
        }
        
        /* Button hover effect - slight lift */
        .cta-button:hover {
            transform: translateY(-2px);
            box-shadow: 0 4px 8px rgba(0,0,0,0.2);
        }
        
        /* ==================== FEATURES SECTION (MOBILE) ==================== */
        /* Section showing platform benefits */
        .features {
            padding: 2rem 0;
            background-color: white;
        }
        
        .section-title {
            text-align: center;
            font-size: 1.5rem;
            margin-bottom: 1.5rem;
            color: #2563eb;
        }
        
        /* Grid layout for feature cards - 1 column on mobile */
        .features-grid {
            display: grid;
            grid-template-columns: 1fr;
            gap: 1.5rem;
            margin-top: 1.5rem;
        }
        
        /* Individual feature card */
        .feature-card {
            background-color: #f9fafb;
            padding: 2rem;
            border-radius: 8px;
            text-align: center;
            transition: transform 0.3s, box-shadow 0.3s;
        }
        
        /* Card hover effect */
        .feature-card:hover {
            transform: translateY(-5px);
            box-shadow: 0 5px 15px rgba(0,0,0,0.1);
        }
        
        /* Icon placeholder in feature cards */
        .feature-icon {
            font-size: 3rem;
            margin-bottom: 1rem;
            color: #2563eb;
        }
        
        .feature-card h3 {
            margin-bottom: 1rem;
            color: #1e40af;
        }
        
        /* ==================== COURSES PREVIEW SECTION (MOBILE) ==================== */
        .courses-preview {
            padding: 2rem 0;
            background-color: #f4f4f4;
        }
        
        /* Grid for course cards - 1 column on mobile */
        .courses-grid {
            display: grid;
            grid-template-columns: 1fr;
            gap: 1.5rem;
            margin-top: 1.5rem;
        }
        
        /* Individual course card */
        .course-card {
            background-color: white;
            border-radius: 8px;
            overflow: hidden;
            box-shadow: 0 2px 5px rgba(0,0,0,0.1);
            transition: transform 0.3s;
        }
        
        .course-card:hover {
            transform: translateY(-5px);
        }
        
        /* Course image placeholder */
        .course-image {
            background-color: #dbeafe;
            height: 150px;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 3rem;
            color: #2563eb;
        }
        
        /* Course information section */
        .course-info {
            padding: 1.5rem;
        }
        
        .course-info h3 {
            color: #1e40af;
            margin-bottom: 0.5rem;
        }
        
        .course-info p {
            color: #666;
            font-size: 0.9rem;
        }
        
        /* ==================== FOOTER SECTION ==================== */
        footer {
            background-color: #1e293b;
            color: white;
            padding: 2rem 0;
            text-align: center;
            margin-top: 3rem;
        }
        
        footer p {
            margin-bottom: 0.5rem;
        }
        
        /* Footer links styling */
        .footer-links {
            margin-top: 1rem;
        }
        
        .footer-links a {
            color: #93c5fd;
            text-decoration: none;
            margin: 0 1rem;
        }
        
        .footer-links a:hover {
            color: white;
        }
        
        /* ==================== MEDIA QUERIES FOR LARGER SCREENS ==================== */
        /* These styles override mobile styles for tablets and desktops */
        
        /* Tablets and above (768px and up) */
        @media (min-width: 768px) {
            /* Logo larger on tablets */
            .logo {
                font-size: 1.8rem;
            }
            
            /* Hide hamburger menu on tablets and up */
            .hamburger {
                display: none;
            }
            
            /* Show navigation horizontally on tablets and up */
            nav ul {
                display: flex; /* Always show, override JavaScript */
                flex-direction: row;
                width: auto;
                gap: 2rem;
                padding: 0;
            }
            
            /* Navigation items inline */
            nav ul li {
                width: auto;
                padding: 0;
            }
            
            /* Navigation hover effect changes for desktop */
            nav a:hover {
                color: #dbeafe;
                background-color: transparent;
            }
            
            /* Hero section larger on tablets */
            .hero {
                padding: 3rem 0;
            }
            
            .hero h1 {
                font-size: 2.2rem;
            }
            
            .hero p {
                font-size: 1.1rem;
            }
            
            /* Features grid - 2 columns on tablets */
            .features-grid {
                grid-template-columns: repeat(2, 1fr);
            }
            
            /* Courses grid - 2 columns on tablets */
            .courses-grid {
                grid-template-columns: repeat(2, 1fr);
            }
            
            /* Section titles larger */
            .section-title {
                font-size: 1.8rem;
            }
        }
        
        /* Desktop and above (1024px and up) */
        @media (min-width: 1024px) {
            /* Hero section full size on desktop */
            .hero {
                padding: 4rem 0;
            }
            
            .hero h1 {
                font-size: 2.5rem;
            }
            
            .hero p {
                font-size: 1.2rem;
                margin-bottom: 2rem;
            }
            
            /* Features section more padding */
            .features {
                padding: 3rem 0;
            }
            
            /* Features grid - 3 columns on desktop */
            .features-grid {
                grid-template-columns: repeat(3, 1fr);
                gap: 2rem;
                margin-top: 2rem;
            }
            
            /* Courses section more padding */
            .courses-preview {
                padding: 3rem 0;
            }
            
            /* Courses grid - 4 columns on desktop */
            .courses-grid {
                grid-template-columns: repeat(4, 1fr);
                margin-top: 2rem;
            }
            
            /* Section titles full size */
            .section-title {
                font-size: 2rem;
                margin-bottom: 2rem;
            }
        }