/* Mobile Responsive CSS */
* {
    box-sizing: border-box;
}

/* Hero Section */
@media (max-width: 768px) {
    h1 { font-size: 1.8rem !important; }
    h2 { font-size: 1.5rem !important; }
    h3 { font-size: 1.2rem !important; }
    h4 { font-size: 1rem !important; }
}

@media (max-width: 640px) {
    h1 { font-size: 1.5rem !important; }
    h2 { font-size: 1.3rem !important; }
    h3 { font-size: 1rem !important; }
}

/* Main Grid Layout */
@media (max-width: 1024px) {
    .main-grid { 
        grid-template-columns: 1fr !important;
    }
    .sidebar-sticky {
        position: static !important;
    }
}

/* Mobile adjustments */
@media (max-width: 768px) {
    .container {
        padding-left: 16px !important;
        padding-right: 16px !important;
    }
    
    .hero-section {
        padding: 40px 0 !important;
    }
    
    .hero-title {
        font-size: 1.5rem !important;
    }
    
    .stats-grid {
        gap: 15px !important;
        flex-direction: column !important;
    }
    
    .course-image {
        height: 250px !important;
    }
    
    .tab-buttons {
        gap: 10px !important;
        overflow-x: auto !important;
        flex-wrap: nowrap !important;
    }
    
    .tab-button {
        font-size: 0.85rem !important;
        padding: 10px !important;
        white-space: nowrap !important;
    }
    
    .button-full {
        width: 100% !important;
    }
    
    .price-display {
        font-size: 2rem !important;
    }
    
    .rating-breakdown {
        grid-template-columns: 1fr !important;
        gap: 15px !important;
    }
    
    .course-card {
        grid-template-columns: 1fr !important;
    }
    
    .related-courses-grid {
        grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)) !important;
        gap: 15px !important;
    }
}

@media (max-width: 640px) {
    .hero-title {
        font-size: 1.3rem !important;
    }
    
    .course-image {
        height: 200px !important;
    }
    
    .button {
        padding: 12px !important;
        font-size: 0.9rem !important;
    }
    
    .sidebar {
        margin-top: 30px !important;
    }
    
    .price-display {
        font-size: 1.8rem !important;
    }
    
    .related-courses-grid {
        grid-template-columns: 1fr !important;
    }

    .materials-grid {
        grid-template-columns: 1fr !important;
    }
    
    .instructor-info {
        flex-direction: column !important;
        text-align: center !important;
    }
}

@media (max-width: 1024px) {
    .materials-grid {
        grid-template-columns: repeat(auto-fill, minmax(250px, 1fr)) !important;
    }
}

/* Tab content responsive */
.tab-content {
    overflow-x: auto !important;
}

/* Sticky sidebar mobile fix */
@media (max-width: 768px) {
    .sticky {
        position: static !important;
        top: auto !important;
    }
}

/* Grid systems */
.grid-2 {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 15px;
}

.grid-3 {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 15px;
}

@media (max-width: 1024px) {
    .grid-3 {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    .grid-2,
    .grid-3 {
        grid-template-columns: 1fr;
    }
}

/* Flex utilities */
.flex-responsive {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

@media (max-width: 768px) {
    .flex-responsive {
        flex-direction: column;
    }
}

/* Touch-friendly buttons */
@media (max-width: 768px) {
    button, a.btn {
        min-height: 44px !important;
        min-width: 44px !important;
    }
}

/* Form elements */
@media (max-width: 768px) {
    textarea, input, select {
        font-size: 16px !important;
    }
}

/* Responsive padding */
@media (max-width: 768px) {
    .section { padding: 30px 0 !important; }
    .card { padding: 15px !important; }
}

@media (max-width: 640px) {
    .section { padding: 20px 0 !important; }
    .card { padding: 12px !important; }
}