It is a subjective thing, but I find it hard to "read"
- blue and gray shades of icons are too close to each other, it is especially disturbing where the icons are the same otherwise (e.g. "branching" icon of boards)
- the envelope icons are just slightly better, since they are fading towards light shades on their top, thus some effort is required for deciding if the envelope is closed or it "contains" some pages
- small thin white letters on light gradient green background do not read well (dates of posts, etc.)