/* ── PDF转换专题页 ── */

.sub-tools-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 1rem;
}

.sub-tool-card {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 1.5rem 1rem;
    border: 1px solid #e8eaf0;
    border-radius: 10px;
    text-decoration: none;
    color: #333;
    transition: border-color 0.2s, box-shadow 0.2s;
    background: #fafbfc;
}

.sub-tool-card:hover {
    border-color: #2563eb;
    box-shadow: 0 2px 8px rgba(37, 99, 235, 0.1);
    text-decoration: none;
}

.sub-tool-icon {
    font-size: 2rem;
    margin-bottom: 0.6rem;
}

.sub-tool-name {
    font-size: 0.95rem;
    font-weight: 600;
    margin-bottom: 0.3rem;
    color: #333;
}

.sub-tool-desc {
    font-size: 0.82rem;
    color: #888;
    text-align: center;
    line-height: 1.4;
}

@media (max-width: 768px) {
    .sub-tools-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

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