Flat theme colors in timeline and flamegraph are unusable

Something has changed the colors. In particular:

• The range mover is not semi-transparent anymore, so you cannot see what is below it.
• The detail window headers are blue now. That woudl be OK by itself.
• The font color in the detail windows is way too light and hardly readable.
• The detail window borders stand out much more now (which also highlights the fact that the range detail window doesn't have a border ...).
• The background of the timeline overview is black now. This is rather irritating because the background of the main timeline is white.