Use font shorthand for ace_editor
Only -webkit prefix for transitions is necessary

Android and iOS safari both support it without the prefix, but hasn’t
for long
Vendor prefixes aren't necessary for box-shadow
px is redundant for zero values
position: fixed triggers display: block
Vendor prefixes are not needed for border-radius
float triggers display: block
Use font shorthand
Keyframes can share values
Use animation and font shorthand
float triggers display block
Merge pull request #2145 from tobiasahlin/clean-up-css

Clean up CSS