Review Board's had the same general look for a long time now, and some

of it hasn't aged particularly well. There's a harshness to many of our

content panes and other parts of the UI, with borders that stand out too

much, colors that are too strong, and UI elements that aren't emphasized

well enough.
While we're not about to unveil a major redesign of Review Board, this

change does clean up much of our common presentation in the following

ways:


Borders are now more subtle throughout the UI, helping to blend in

  better with nearby backgrounds while still providing a visual

  separation. This includes content box borders, field borders in the

  review request, banner borders, and various separators.


Shadows are now placed below content, rather than toward the

  bottom-right, helping keep a more symmetrical feel to content boxes.


Status update icons are now larger, with both success and failure

  icons being enclosed in a filled circle to make them stand out better.

  Colors have been tweaked to fit the general aesthetic.


Status update section headers are also less harsh, andno longer

  rely on the diff color constants.


Diffs in the diff viewer now have more separation (2x the page

  padding). This provides a better visual separation between diffs.


Colors within diffs have been made softer, more pastel, with blue

  section headers instead of brown. This creates an almost "Easter"

  feel, which is more pleasant to look at. In particular, insert/delete

  lines are also far easier on the eyes, especially when looking at

  large blocks of code.


Headers in diffs showing the nearest function/class to expand to

  are now just a little bigger, helping it stand out as a proper header.


In replace lines, the replaced content is now more of a gold, rather

  than a mustard.


Diff text now has a very slightly larger font size, which is easier on

  the eyes on today's modern displays. It's still smaller than GitHub's

  text, with a good balance of readability and being able to fit plenty

  of content on the screen.


Comment bubbles are now pill-shaped, rather than slightly-rounded

  rectangles. This looks nice and stands out better. Colors have also

  been made less harsh.


One thing to note in this change is that there's a lot more hard-coded

colors, rather than reliance on the #rb-ns-ui.colors() constants. This

is intentional. Many of these parts of the UI never mapped to those

color constants to begin with. We'll also be introducing more general

concepts of palettes and mode-specific styless

(light/dark/high-constrast) in Review Board 7. All color usage we have

today is going to be redone as part of that, and as such, it's not worth

altering the base color palettes to try to match these changes today.

Tested the dashboard, review requests (with all possible types of content),

diffs, My Account page, and the administration pages on Chrome and Firefox,

verifying that presentation looked correct.