Time series dark mode colors are barely readable

[n-gao]

The colors used in the time series tab are barely readable with dark mode turned on.
Screenshot:

The main issues are, IMHO, the following:

• The grey color is too similar to the background color
• The grid lines should be dark grey and not white, the white is a stark contrast lowering the perceived contrast of the remaining lines.
• The background color is too bright.

For comparison this is what the same plot looks like in the scalar tab:

Versions:

• TensorBoard 2.10.0
• Chrome: 104.0.5112.101

[bileschi]

Thanks for the FR. This is a good point - the grey color is very close to the grid color.