RE: Colour line sections

The line is broken into 3 sections with the colour changing mid section.

In order to change the line colour at the mid point position I created new series, one for each section colour, that contained twice as many data points as the original line.
The data uses direct links for the main points and a formula to calculate the mid points.
The secondary X axis is also formatted to not cross between categories.

See example workbook for formula