/* Header */
        /* Header */
        .header {
            background: var(--primary);
            color: var(--white);
            box-shadow: 0 0.125rem 0.625rem rgba(0,0,0,0.1);
            position: fixed !important;
            width: 100% !important;
            top: 0 !important;
            left: 0 !important;
            right: 0 !important;
            z-index: 9999 !important;
            backface-visibility: hidden;
            -webkit-backface-visibility: hidden;
            transform: translateZ(0);
            display: block !important;
            visibility: visible !important;
        }

        .nav {
            display: flex;
            justify-content: space-between;
            align-items: center;
            max-width: 100%;
            margin: 0 auto;
            background: var(--primary);
            padding: 0 5%;
        }

        .logo {
            color: var(--white);
            font-size: clamp(1.25rem, 4vw, 1.8rem);
            font-weight: bold;
            text-decoration: none;
        }

        .nav-menu {
            display: flex;
            list-style: none;
            gap: clamp(1rem, 3vw, 2rem);
        }

        .nav-menu a {
            text-decoration: none;
            color: var(--white);
            font-weight: 500;
            transition: color 0.3s;
        }

        .nav-menu a:hover {
            color: var(--secondary);
        }

        .zalo-btn {
            background: var(--secondary);
            color: white;
            padding: 0.5rem 1rem;
            border-radius: 1.5625rem;
            text-decoration: none;
            display: flex;
            align-items: center;
            gap: 0.5rem;
            transition: background 0.3s;
            font-size: 0.9rem;
        }

        .zalo-btn:hover {
            background: var(--accent);
            color: var(--primary);
        }

        /* Mobile menu button - Hamburger to X animation */
        .mobile-menu {
            display: none;
            background: transparent;
            border: none;
            cursor: pointer;
            padding: 0.5rem;
            position: relative;
            z-index: 10001;
            width: 30px;
            height: 30px;
            flex-direction: column;
            justify-content: center;
            align-items: center;
        }

        /* Hamburger icon using CSS */
        .mobile-menu::before,
        .mobile-menu::after,
        .mobile-menu .hamburger-line {
            content: '';
            display: block;
            width: 25px;
            height: 3px;
            background: white;
            transition: all 0.3s ease;
            transform-origin: center;
        }

        .mobile-menu::before {
            transform: translateY(-5px);
        }

        .mobile-menu::after {
            transform: translateY(5px);
        }

        /* Transform to X when active */
        .mobile-menu.active::before {
            transform: rotate(45deg) translateY(5px);
        }

        .mobile-menu.active::after {
            transform: rotate(-45deg) translateY(-5px);
        }

        .mobile-menu.active .hamburger-line {
            opacity: 0;
            transform: scaleX(0);
        }

:root {
	--header-h: 64px;
}

/* Đẩy nội dung xuống dưới header để không bị che */
body {
	padding-top: var(--header-h);
}

/* Đảm bảo nav căn giữa theo chiều cao header */
.header .nav {
	height: var(--header-h);
	align-items: center;
}

/* Header Media Queries */
@media (max-width: 48rem) {
    :root { 
        --header-h: 56px; 
    }
    
    body {
        padding-top: var(--header-h);
    }
    
    .nav-menu {
        display: none;
    }

    .zalo-btn {
        display: none;
    }

    .mobile-menu {
        display: block;
        margin-right: 0;
    }
    
    .nav {
        padding: 0 3%;
    }
}