c9s
http://sass-lang.com/documentation/Sass/Script/Functions.html - [ ] SASS Built-in Functions - [ ] RGB functions - [ ] `rgb($red, $green, $blue)` - [ ] `rgba($red, $green, $blue, $alpha)` - [ ] `red($color)` -...
Replace IfStatement with Block directly if the condition can be reduced to true or false (put in `OptimizeIfStatement` function)
https://developer.mozilla.org/en-US/docs/Web/CSS/color_value
if there is a interpolation node in the expression tree, we shall treat them as string operation. e.g., ``` width: (3+4)#{ "px" }; ``` outputs: ``` width: 7px; ``` since...
width: auto; where the `auto` should be unquoted string `auto` And ``` font-family: "Arial"; ``` where the "Arial" should be double-qouted string "Arial";