.settings-panel { background: var(--card-bg); flex: 1; padding: 25px; border-radius: var(--radius); box-shadow: 0 4px 12px rgba(0,0,0,0.08); border: 1px solid var(--border-color); }
       
        .control-group { margin-bottom: 15px; }
        .control-group label { display: block; margin-bottom: 6px; font-weight: 600; font-size: 0.85rem; color: var(--text-main); }
        .textarea-input { width: 100%; padding: 10px; border: 1px solid var(--border-color); border-radius: 8px; font-size: 0.9rem; background: #fafafa; font-family: monospace; resize: vertical; min-height: 120px; }
        .textarea-input:focus { outline: 2px solid var(--primary-color); background: #fff; }

        .checkbox-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 8px; margin-top: 10px; }
        .checkbox-label { display: flex; align-items: center; gap: 8px; font-size: 0.85rem; color: var(--text-main); cursor: pointer; }
        .checkbox-label input { width: 16px; height: 16px; cursor: pointer; accent-color: var(--primary-color); }

        .action-btn { width: 100%; background-color: var(--primary-color); color: white; border: none; border-radius: 8px; padding: 12px; font-size: 1rem; font-weight: 600; cursor: pointer; transition: background-color 0.2s; margin-top: 10px; }
        .action-btn:hover { background-color: var(--primary-hover); }

        .preview-panel { background: #fff; flex: 1; padding: 25px; border-radius: var(--radius); box-shadow: 0 4px 12px rgba(0,0,0,0.08); border: 1px solid var(--border-color); display: flex; flex-direction: column; justify-content: center; }
        
        .result-box { width: 100%; min-height: 120px; padding: 12px; background: #f0f4f8; border: 1px solid var(--border-color); border-radius: 8px; font-family: monospace; font-size: 0.9rem; color: var(--text-main); word-break: break-all; white-space: pre-wrap; margin-top: 8px; margin-bottom: 15px; }

        @media (max-width: 768px) { 
            .main-container { flex-direction: column; } 
            .checkbox-grid { grid-template-columns: 1fr; }
        }