Added :hover colour change to blue buttons

[tagawa]

Description :

Added a darker shade of blue when buttons are hovered over or in focus.

Reviewer notes :

References issues / PRs:

#

Who should be informed of this change?

@jbarrett @chrismorast

Does this change have significant privacy, security, performance or deployment implications?

Checklist :

• [ ] Back end tests (perl, scripts)
• [ ] Front end tests (js, integration)
• Browser verification
  • [ ] IE
  • [ ] Chrome
  • [ ] Firefox
  • [ ] Safari
  • [ ] Opera
• Mobile verification
  • [ ] iOS
  • [ ] Android

[tagawa]

@jbarrett Would you be able to add this to staging as well please, for a bit more testing?

[tagawa]

Thanks @jbarrett