Fix #12025 and minify styles
mv .img-responsive docs from Overview to Images section
Improve alignment of the dashboard placeholder images
Fixes #12435
add note to CONTRIBUTING.md about `outline: none`
Tightening up popover arrow css scope to apply only to direct descendant arrows.
Allow the bootstrap package in npm to expose css and less
Remove comma first rule

Removes outdated coding style rule.
die tabs, die!
fix #12566
Add examples/**/*css in the csslint task.

Fixes #12457.
Examples: fix csslint errors.
fix #12494 in the migration docs
Merge pull request #12533 from 1000hz/tighten-popover-arrows-scope

Scope popover arrow css to direct descendant
Merge pull request #12553 from ZDroid/nocf

Remove comma first rule
Don't offset customizer alert, grunt dist
Merge pull request #12466 from XhmikosR/12457

Add examples/css in the csslint task.
Add examples/**/*.css in csscomb task.
Remove double semicolon.
Merge pull request #12568 from XhmikosR/examples-csscomb

Add examples in csscomb
Merge pull request #12499 from twbs/move-responsive-imgs-sect

move .img-responsive docs from Overview to Images section