Contrast should be used to make useful UI elements easy to find, and blend in less important elements.
In the current design, contrast is all backwards. It makes all the unimportant UI elements stick out, and all the elements that need to be visible are basically hidden.
Two things are necessary in order to fix this:
- Make the unimportant UI elements less contrasted: background, minor links and callouts badges, logo
- Make the important, "business" elements more contrasted.
You can achieve this by making the background lighter, the font on the left column bigger and bolder, and avoid the hideous super-saturated yellow and green, in favour of more natural tints.
Please refer to the image below: