Background rects should be a bit taller, and reach all the way to the top of the text.
The color makes the text had to read... not sure how to fix this, so I would leave it for now. In the long run maybe if the color is more than a certain intensity, then invert the text color?
Heatmap should always be visible, not only on mouseover.
1 and 3 should be fixed before merging. They should be pretty minor. 2 will be left for future work.
3 nits:
Background rects should be a bit taller, and reach all the way to the top of the text.
The color makes the text had to read... not sure how to fix this, so I would leave it for now. In the long run maybe if the color is more than a certain intensity, then invert the text color?
Heatmap should always be visible, not only on mouseover.
1 and 3 should be fixed before merging. They should be pretty minor. 2 will be left for future work.