autoprefixer
Prefix CSS and SCSS with Autoprefixer
Install
$ apm install autoprefixer
Or, Settings → Install → Search for autoprefixer
Usage
Prefix
- 
Open the Command Palette and type Autoprefixer: Prefix. 
- 
In an HTML file, select the CSS, open the Command Palette, and type Autoprefixer: Prefix. 
Remove Prefixes
- 
Open the Command Palette and type Autoprefixer: Remove Prefixes. 
- 
In an HTML file, select the CSS, open the Command Palette, and type Autoprefixer: Remove Prefixes. 
Settings
There's a Run on Save option and more in the settings.
Keyboard shortcut
Set the keyboard shortcut you want in your keymap:
'atom-text-editor':
	'cmd-shift-x': 'autoprefixer:prefix'
	'cmd-shift-u': 'autoprefixer:remove-prefixes'
License
MIT © Sindre Sorhus