/* --- 1. Nền toàn bộ trang (Kho tài liệu) --- */
.vb-page-wrapper {
    background: #1a1a1a url('https://images.unsplash.com/photo-1507842217343-583bb7270b66?auto=format&fit=crop&q=80&w=2000');
    background-size: cover;
    background-position: center;
    background-attachment: fixed;
    min-height: 100vh;
    padding: 60px 0;
}

.vb-wrapper {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* --- 2. Tiêu đề & Bộ lọc --- */
.vb-header h1 {
    font-size: 2.8rem;
    color: #ffffff;
    text-shadow: 0 4px 10px rgba(0,0,0,0.8);
    margin-bottom: 30px;
    text-align: center;
    text-transform: uppercase;
    font-weight: 800;
}

.vb-filter {
    display: flex;
    justify-content: center;
    gap: 12px;
    margin-bottom: 50px;
    background: rgba(255, 255, 255, 0.1);
    padding: 15px;
    border-radius: 50px;
    backdrop-filter: blur(8px);
    border: 1px solid rgba(255,255,255,0.2);
    flex-wrap: wrap;
}

.filter-btn {
    padding: 10px 25px;
    border: 1px solid #d4af37;
    background: transparent;
    color: #ffffff;
    border-radius: 25px;
    cursor: pointer;
    transition: 0.3s;
    font-weight: 600;
}

.filter-btn.active, .filter-btn:hover {
    background: #d4af37;
    color: #1a1a1a;
    box-shadow: 0 0 15px rgba(212, 175, 55, 0.4);
}

/* --- 3. Card Văn bản (Nền ảnh tập tin & Texture giấy) --- */
.vb-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 30px;
}

.vb-card {
    position: relative;
    border-radius: 12px;
    overflow: hidden;
    min-height: 280px;
    display: flex;
    flex-direction: column;
    padding: 25px;
    transition: all 0.4s cubic-bezier(0.165, 0.84, 0.44, 1);
    box-shadow: 0 10px 20px rgba(0,0,0,0.4);
    border: 1px solid rgba(255,255,255,0.1);
    
    /* Background: Kết hợp Texture giấy nhám và ảnh tập tin */
    background-image: linear-gradient(to bottom, rgba(255, 255, 255, 0.88), rgba(255, 255, 255, 0.95)), 
                      url('https://i.pinimg.com/736x/6c/a6/00/6ca600b76530a3f383986dff7410ae79.jpg'),
                      url('https://images.unsplash.com/photo-1586075010923-2dd4570fb338?auto=format&fit=crop&q=80&w=500');
    background-size: cover;
    background-position: center;
}

/* Decor góc kẹp tài liệu Gold */
.vb-card::after {
    content: "";
    position: absolute;
    top: 0;
    right: 0;
    width: 45px;
    height: 45px;
    background: linear-gradient(135deg, transparent 50%, #d4af37 50%);
    opacity: 0.9;
    z-index: 3;
}

.vb-card:hover {
    transform: translateY(-12px) rotate(-1deg);
    box-shadow: 0 25px 50px rgba(0,0,0,0.6);
    border-color: #d4af37;
}

.vb-tag {
    background: #d4af37;
    color: #fff;
    font-size: 0.7rem;
    padding: 4px 12px;
    border-radius: 4px;
    font-weight: 700;
    width: fit-content;
    z-index: 5;
    text-transform: uppercase;
}

.vb-title {
    font-size: 1.15rem;
    color: #1a1a1a;
    margin: 15px 0;
    font-weight: 800;
    line-height: 1.5;
    z-index: 5;
    text-shadow: 0.5px 0.5px 0px rgba(255,255,255,0.8);
}

.vb-type-icon {
    width: 40px;
    filter: drop-shadow(1px 1px 2px rgba(0,0,0,0.1));
    z-index: 5;
    margin-bottom: 10px;
}

/* Nút hành động */
.vb-actions {
    display: flex;
    gap: 10px;
    margin-top: auto;
    z-index: 10;
}

.btn-view, .btn-download {
    flex: 1;
    text-align: center;
    padding: 10px 5px;
    border-radius: 6px;
    font-size: 0.85rem;
    font-weight: 700;
    text-decoration: none;
    transition: 0.3s;
}

.btn-view {
    background: rgba(0, 0, 0, 0.05);
    color: #444;
    border: 1px solid rgba(0,0,0,0.1);
}

.btn-view:hover {
    background: rgba(0, 0, 0, 0.1);
}

.btn-download {
    background: #1a1a1a;
    color: #d4af37;
    border: 1px solid #d4af37;
}

.btn-download:hover {
    background: #d4af37;
    color: #1a1a1a;
}

/* Modal Tài liệu */
.vb-modal {
    display: none;
    position: fixed;
    z-index: 9999;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0,0,0,0.9);
    backdrop-filter: blur(10px);
}

.vb-modal-content {
    background-color: #fff;
    margin: 5% auto;
    padding: 5px;
    border-radius: 8px;
    width: 85%;
    max-width: 1000px;
    position: relative;
    box-shadow: 0 0 30px rgba(0,0,0,0.5);
}

.close-modal {
    position: absolute;
    right: -15px;
    top: -45px;
    color: #fff;
    font-size: 35px;
    font-weight: bold;
    cursor: pointer;
}