@media (max-width: 992px) {
    .container {
        padding: 0 30px;
    }
    h1 { font-size: 2.4rem; }
    h2 { font-size: 2rem; }
    .hero-banner h1 { font-size: 2.8rem; }

    .footer-grid {
        grid-template-columns: 1fr 1fr;
    }
}


@media (max-width: 768px) {
    .main-nav {
        display: none;
        position: absolute;
        top: 70px;
        left: 0;
        right: 0;
        background-color: #fff;
        width: 100%;
        flex-direction: column;
        text-align: center;
        box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    }
    .main-nav.active {
        display: flex;
    }
    .main-nav ul {
        flex-direction: column;
        width: 100%;
    }
    .main-nav ul li {
        margin: 0;
    }
    .main-nav ul li a {
        display: block;
        padding: 15px;
        border-bottom: 1px solid var(--border-color);
    }
    
    .mobile-nav-toggle {
        display: block;
        background: none;
        border: none;
        font-size: 2rem;
        cursor: pointer;
        color: var(--dark-color);
    }

    .solutions-grid {
        grid-template-columns: repeat(2, 1fr);
        height: auto;
        aspect-ratio: 1 / 1;
    }
    
    .footer-grid {
        grid-template-columns: 1fr;
        text-align: center;
    }
}

@media (max-width: 576px) {
    h1, .hero-banner h1 { font-size: 2rem; }
    h2 { font-size: 1.8rem; }
    
    .hero-banner { padding: 80px 0; }
    
    .advantage-grid, .product-card-grid {
        grid-template-columns: 1fr;
    }

    .solutions-grid {
        grid-template-columns: 1fr;
        aspect-ratio: initial;
        height: auto;
    }

    .solution-item {
        min-height: 200px;
    }
}```

---

#### **File 4: `js/main.js`**

```javascript
document.addEventListener('DOMContentLoaded', function() {
    const mobileNavToggle = document.querySelector('.mobile-nav-toggle');
    const mainNav = document.querySelector('.main-nav');

    if (mobileNavToggle && mainNav) {
        mobileNavToggle.addEventListener('click', function() {
            mainNav.classList.toggle('active');
        });
    }
});