#lightbox {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background-color: rgba(0, 0, 0, 0.9);
            /* Nền đen mờ */
            z-index: 9999;
            /* Đảm bảo luôn nằm trên cùng */
            display: none;
            /* Mặc định ẩn */
            align-items: center;
            justify-content: center;
            backdrop-filter: blur(10px);
            /* Làm mờ nền trang web */
            cursor: zoom-out;
        }

        #lightbox.active {
            display: flex;
            /* Hiện khi có class active */
        }

        #lightbox img {
            max-width: 90%;
            max-height: 85%;
            border-radius: 10px;
            box-shadow: 0 0 50px rgba(0, 0, 0, 0.5);
            transform: scale(0.8);
            transition: transform 0.3s ease;
        }

        #lightbox.active img {
            transform: scale(1);
            /* Hiệu ứng phóng to khi hiện */
        }

        .close-btn {
            position: absolute;
            top: 20px;
            right: 30px;
            color: white;
            font-size: 60px;
            font-weight: 200;
            cursor: pointer;
            background: none;
            border: none;
            line-height: 1;
        }

        .close-btn:hover {
            color: #0ea5e9;
        }

        :root {
            --fb-bg: #ffffff;
            --accent: #0ea5e9;
            --deep-navy: #020617;
        }

        body {
            background-color: #f8fafc;
            font-family: 'Inter', sans-serif;
            overflow-x: hidden;
            scroll-behavior: smooth;
        }

        .font-art {
            font-family: 'Playfair Display', serif;
        }

        /* --- LƯỚI GRID ĐỒNG ĐỀU (THAY CHO MASONRY) --- */
        .masonry-grid {
            display: grid;
            grid-template-columns: repeat(1, minmax(0, 1fr));
            gap: 2.5rem;
            width: 100%;
        }

        @media (min-width: 640px) {
            .masonry-grid {
                grid-template-columns: repeat(2, minmax(0, 1fr));
            }
        }

        @media (min-width: 1024px) {
            .masonry-grid {
                grid-template-columns: repeat(3, minmax(0, 1fr));
            }
        }

        @media (min-width: 1440px) {
            .masonry-grid {
                grid-template-columns: repeat(4, minmax(0, 1fr));
            }
        }

        /* --- GALLERY ITEM - HÌNH CHỮ NHẬT BẰNG NHAU --- */
        .gallery-item {
            position: relative;
            width: 100%;
            aspect-ratio: 4 / 3;
            /* Cố định tỉ lệ hình chữ nhật 4:3 cho tất cả các ô */
            border-radius: 1.2rem;
            overflow: hidden;
            background: white;
            box-shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.1);
            transition: all 0.6s cubic-bezier(0.23, 1, 0.32, 1);
            cursor: pointer;
        }

        .gallery-item:hover {
            transform: translateY(-12px) scale(1.03);
            box-shadow: 0 30px 60px -12px rgba(0, 0, 0, 0.25);
            z-index: 50;
        }

        .gallery-image {
            width: 100%;
            height: 100%;
            /* Lấp đầy chiều cao ô */
            object-fit: cover;
            /* Zoom và cắt ảnh nếu không vừa tỉ lệ 4:3 */
            display: block;
            transition: transform 1.5s cubic-bezier(0.23, 1, 0.32, 1);
        }

        .gallery-item:hover .gallery-image {
            transform: scale(1.15);
        }

        /* Lớp phủ mô tả */
        .gallery-overlay {
            position: absolute;
            inset: 0;
            background: linear-gradient(to top, rgba(2, 6, 23, 0.9) 0%, rgba(2, 6, 23, 0.2) 60%, transparent 100%);
            opacity: 0;
            transition: all 0.5s ease;
            display: flex;
            flex-direction: column;
            justify-content: flex-end;
            padding: 1.5rem;
        }

        .gallery-item:hover .gallery-overlay {
            opacity: 1;
        }

        /* --- SPOTLIGHT & OTHERS --- */
        #categoryDetails {
            max-width: 1600px !important;
            margin-bottom: 5rem;
            padding: 4rem !important;
            border-radius: 3.5rem !important;
            transition: all 0.8s cubic-bezier(0.34, 1.56, 0.64, 1);
            background: linear-gradient(135deg, #020617 0%, #0f172a 100%);
            box-shadow: 0 50px 100px -20px rgba(2, 6, 23, 0.7);
        }

        #categoryDetails.active {
            opacity: 1;
            transform: scale(1) translateY(0);
        }

        .fb-post-box {
            background: white;
            border-radius: 12px;
            border: 1px solid #e5e7eb;
            padding: 14px 0;
            width: 100%;
            box-shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
            transition: all 0.4s ease;
            text-decoration: none;
            display: block;
        }

        .filter-btn {
            padding: 0.8rem 2.2rem;
            border-radius: 2rem;
            border: 1px solid #e2e8f0;
            background: white;
            font-weight: 800;
            font-size: 0.75rem;
            transition: all 0.3s;
            letter-spacing: 0.1em;
            color: #64748b;
        }

        .filter-btn.active {
            background: #0ea5e9;
            color: white;
            border-color: #0ea5e9;
            transform: scale(1.05);
        }

        .hidden-item {
            display: none !important;
        }

        /* --- SMART SPARSE GRID (KHI ÍT ẢNH) --- */
        .masonry-grid.sparse {
            display: flex !important;
            justify-content: center !important;
            flex-wrap: wrap !important;
        }

        .masonry-grid.sparse .gallery-item {
            width: 400px !important;
            /* Độ rộng ảnh khi căn giữa */
        }

        .project-link-card {
            background: rgba(255, 255, 255, 0.05);
            border: 1px solid rgba(255, 255, 255, 0.1);
            border-radius: 16px;
            padding: 16px;
            transition: all 0.3s ease;
            display: flex;
            align-items: center;
            gap: 12px;
            text-decoration: none;
        }

        .project-link-card:hover {
            background: rgba(255, 255, 255, 0.12);
            transform: translateX(8px);
            border-color: #0ea5e9;
        }

        .light-beam {
            position: fixed;
            width: 60vw;
            height: 60vw;
            background: radial-gradient(circle, rgba(14, 165, 233, 0.15) 0%, transparent 70%);
            z-index: -1;
            pointer-events: none;
            filter: blur(50px);
            animation: lightMove 25s infinite alternate;
        }

        @keyframes lightMove {
            0% {
                transform: translate(-20%, -20%);
            }

            100% {
                transform: translate(40%, 20%);
            }
        }

        /* ===== UNIFIED NAVIGATION CSS ===== */
/* ===== TINH CHỈNH MENU: NHỎ GỌN & XANH CYAN ===== */
:root {
    --header-height: 4.5rem; /* Giảm chiều cao xuống cho gọn */
    --brand-blue: #00adef;   /* Màu xanh chính xác từ ảnh bạn gửi */
    --text-dark: #1e293b;
    --text-gray: #64748b;
}

.main-header {
    width: 100%;
    position: fixed;
    top: 0;
    left: 0;
    z-index: 1000;
    background: transparent;
    transition: all 0.3s ease;
}

/* Khi cuộn chuột */
.main-header.scrolled {
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(10px);
    height: 4rem;
    box-shadow: 0 2px 15px rgba(0, 0, 0, 0.05);
}

.nav-container {
    max-width: 100%;
    padding: 0 3rem; /* Khoảng cách lề vừa phải */
    height: 100%;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

/* LOGO NHỎ GỌN */
.nav-logo {
    font-family: 'Be Vietnam Pro', sans-serif;
    font-size: 1.6rem; /* Giảm size logo */
    font-weight: 800;
    color: var(--text-dark);
    text-decoration: none;
    letter-spacing: -0.5px;
}

.brand-blue {
    color: var(--brand-blue);
}

/* MENU LINKS THANH THOÁT */
.nav-list {
    display: flex;
    column-gap: 2.5rem; /* Khoảng cách các mục vừa đủ */
    list-style: none;
}

.nav-link {
    font-family: 'Inter', sans-serif;
    font-size: 0.9rem; /* Chữ nhỏ lại xíu cho sang */
    font-weight: 600;
    color: var(--text-gray);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    text-decoration: none;
    position: relative;
    transition: 0.3s;
}

.nav-link:hover, .active-link {
    color: var(--brand-blue);
}

/* Hiệu ứng gạch chân đơn giản màu xanh */
.nav-link::after {
    content: "";
    position: absolute;
    bottom: -6px;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--brand-blue);
    transition: width 0.3s ease;
}

.nav-link:hover::after, .active-link::after {
    width: 100%;
}

/* MOBILE RESPONSIVE */
@media screen and (max-width: 767px) {
    .nav-container { padding: 0 1.5rem; }
    
    .nav-menu {
        position: fixed;
        top: -100%;
        left: 0;
        width: 100%;
        background: white;
        padding: 4rem 0;
        text-align: center;
        transition: 0.4s;
        box-shadow: 0 4px 10px rgba(0,0,0,0.1);
    }
    
    .nav-list { flex-direction: column; row-gap: 2rem; }
    .nav-toggle { font-size: 1.5rem; color: var(--text-dark); cursor: pointer; }
    .nav-close { position: absolute; top: 1rem; right: 1.5rem; font-size: 2rem; cursor: pointer; }
    .show-menu { top: 0 !important; }
}

@media screen and (min-width: 768px) {
    .nav-toggle, .nav-close { display: none; }
}