Feature request: color of lines, timeline orientation

[carbonmetrics]

Thank you for making this package available! I have two feature requests.

First, the lines from the main timeline to the labels are pretty dark grey and interfere with the text. Can you introduce an option in which you can set this to a lighter grey? (or another colour).

Second, if there are many events then it is much better to orient the timeline vertically. i now had to resort to rotate the page, but that is not ideal.