how can I change the color of lines related to future speculations to highlight them from what has already happened?

To enhance your graduation thesis and clearly differentiate future speculations from historical data, you can customize the color of specific segments in your chart. Most spreadsheet software allows you to select individual data series or points, enabling you to highlight future forecasts distinctively. By changing the color of these lines, you effectively guide your audience's attention, making your analysis of the company's index evolution more intuitive. This visual distinction not only improves clarity but also emphasizes the importance of your future predictions.