/* --- Cài đặt chung --- */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Roboto', sans-serif;
    background-color: #f4f7f9;
    color: #444;
    line-height: 1.6;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
}

/* --- Nút quay lại & Tiêu đề --- */
.back-button {
    display: inline-block;
    margin-bottom: 2rem;
    color: #555;
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
}

.back-button:hover {
    color: #F9A825;
}

.back-button i {
    margin-right: 0.5rem;
}

.main-header {
    text-align: center;
    margin-bottom: 3rem;
}

.main-header h1 {
    font-family: 'Montserrat', sans-serif;
    font-size: 2.8rem;
    color: #2c3e50;
    margin-bottom: 0.5rem;
}

.main-header h1 i {
    color: #F9A825; /* Scratch Orange Color */
    margin-right: 1rem;
}

.main-header p {
    font-size: 1.1rem;
    color: #7f8c8d;
}

/* --- Lưới tài liệu --- */
.document-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
}

/* --- Thẻ tài liệu --- */
.doc-card {
    background-color: #ffffff;
    border-radius: 10px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.05);
    text-decoration: none;
    color: inherit;
    display: flex;
    flex-direction: column;
    overflow: hidden;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    border: 1px solid #e0e0e0;
}

.doc-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
}

.doc-card-content {
    padding: 1.5rem;
    flex-grow: 1; /* Đẩy footer xuống dưới */
}

.pdf-icon {
    font-size: 2.5rem;
    color: #E53935; /* PDF Red Color */
    margin-bottom: 1rem;
}

.doc-title {
    font-family: 'Montserrat', sans-serif;
    font-size: 1.25rem;
    color: #34495e;
    margin-bottom: 0.5rem;
}

.doc-subtitle {
    font-size: 0.9rem;
    color: #95a5a6;
}

.doc-card-footer {
    background-color: #f7f7f7;
    border-top: 1px solid #e0e0e0;
    color: #333;
    font-weight: 500;
    padding: 0.8rem 1.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: all 0.3s ease;
}

.doc-card:hover .doc-card-footer {
    background-color: #F9A825;
    color: white;
    border-color: #F9A825;
}

/* --- Responsive cho màn hình nhỏ --- */
@media (max-width: 768px) {
    .main-header h1 {
        font-size: 2.2rem;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 1rem;
    }
    .main-header h1 {
        font-size: 1.8rem;
    }
    .main-header p {
        font-size: 1rem;
    }
}