* Add support for importing plain CSS files. They can only be imported *without*
an extension—for example, `import "style"` will import `style.css`. Plain CSS
files imported this way only support standard CSS features, not Sass
extensions.
See [the proposal][css-import] for details.
* Add support for CSS's `min()` and `max()` [math functions][]. A `min()` and
`max()` call will continue to be parsed as a Sass function if it involves any
Sass-specific features like variables or function calls, but if it's valid
plain CSS (optionally with interpolation) it will be emitted as plain CSS instead.
See [the proposal][css-min-max] for details.
* Add support for range-format media features like `(10px < width < 100px)`. See
[the proposal][media-ranges] for details.
* Normalize escape codes in identifiers so that, for example, `éclair` and
`\E9clair` are parsed to the same value. See
[the proposal][identifier-escapes] for details.
* Don't choke on a [byte-order mark][] at the beginning of a document when
running in JavaScript.
[math functions]: https://drafts.csswg.org/css-values/#math-function
[css-import]: https://github.com/sass/language/blob/master/accepted/css-imports.md
[css-min-max]: https://github.com/sass/language/blob/master/accepted/min-max.md
[media-ranges]: https://github.com/sass/language/blob/master/accepted/media-ranges.md
[identifier-escapes]: https://github.com/sass/language/blob/master/accepted/identifier-escapes.md
[byte-order mark]: https://en.wikipedia.org/wiki/Byte_order_mark
Command-Line Interface
* The `--watch` command now continues to recompile a file after a syntax error
has been detected.
Dart API
* Added a `Syntax` enum to indicate syntaxes for Sass source files.
* The `compile()` and `compileAsync()` functions now parse files with the `.css`
extension as plain CSS.
* Added a `syntax` parameter to `compileString()` and `compileStringAsync()`.
* Deprecated the `indented` parameter to `compileString()` and `compileStringAsync()`.
* Added a `syntax` parameter to `new ImporterResult()` and a
`ImporterResult.syntax` getter to set the syntax of the source file.
* Deprecated the `indented` parameter to `new ImporterResult()` and the
`ImporterResult.indented` getter in favor of `syntax`.