/* =========================================
   RESPONSIVE DESIGN (MỌI THIẾT BỊ)
   ========================================= */

.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    color: #333;
    font-size: 24px;
    cursor: pointer;
    margin-left: 15px;
    padding: 5px;
}

/* Tablet (Màn hình < 1024px) */
@media (max-width: 1024px) {
    .container {
        max-width: 95%;
    }
    
    .car-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .achievement-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 20px;
    }
}

/* Điện thoại & Tablet nhỏ (Màn hình < 768px) */
@media (max-width: 768px) {
    .header-container {
        padding: 10px 15px;
    }

    .mobile-menu-btn {
        display: block;
    }

    .navbar {
        position: absolute;
        top: 100%;
        left: 0;
        width: 100%;
        background: #fff;
        box-shadow: 0 10px 15px rgba(0,0,0,0.1);
        display: none; 
        z-index: 1000;
    }

    .navbar.active {
        display: block;
    }

    .navbar ul {
        flex-direction: column;
        padding: 20px;
    }

    .navbar ul li {
        margin: 10px 0;
        width: 100%;
    }

    .navbar ul li a {
        display: block;
        padding: 10px 0;
    }

    .search-form {
        flex-direction: column;
        padding: 20px;
    }

    .search-form .form-group {
        border-right: none;
        border-bottom: 1px solid #eee;
        padding: 15px 0;
        width: 100%;
    }

    .search-form .btn-group {
        padding-top: 15px;
    }

    .hero-content h2 {
        font-size: 28px;
    }

    .row {
        flex-direction: column;
    }

    .col-4, .col-8 {
        width: 100% !important;
        margin-bottom: 20px;
    }

    .page-layout {
        flex-direction: column;
    }

    .sidebar {
        width: 100%;
        margin-bottom: 30px;
    }

    .footer-container {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .footer-col ul li {
        display: inline-block;
        margin: 0 10px;
    }
}

@media (max-width: 480px) {
    .car-grid {
        grid-template-columns: 1fr;
    }

    .hero-content h2 {
        font-size: 24px;
    }

    .btn {
        width: 100%;
        margin-bottom: 10px;
    }

    .header-tools {
        display: flex;
        align-items: center;
    }

    #loginBtn, #registerBtn {
        font-size: 12px;
        padding: 8px 12px;
    }
}