If there are values less than 0 in the histogram, you can highlight these negative values by changing the color. It is common practice to set the negative column color to a different color from the positive column color, such as red. In this way, columns with negative values can stand out in the whole chart, reminding observers of the existence of these negative values.

Reason explanation: The reason for changing the color of values less than 0 in the histogram is to highlight these negative values and make them more conspicuous in the chart. This can help observers understand the distribution of data more easily and pay attention to and analyze negative values.

Extended content: In addition to color changes, other visual effects can be used to highlight negative values, such as changing the style of columns, thickening the borders of columns, and adding negative identifiers. These methods are helpful to increase the visibility of negative values and improve the information transmission effect of charts.

In addition, for the values less than 0 in the histogram, we can further analyze and explore the causes of negative values. This may be due to negative growth or some factors. By comparing the data in different time periods or categories, combined with other relevant information, we can deeply understand the reasons and effects behind negative values, and take corresponding measures to improve or adjust them.