Sass 3.4.17 发布，此版本更新内容如下：
Allow passing calc values to rgb/hsl color constructors.
The source map end character for lists now correctly uses the end of the list instead of the end of the first element in the list.
Fix up some edge cases where extra semicolons could be added to unknown directives in compressed mode.
If you try to do a stupid color operation with a stupid value, the error message will now be less stupid than it was.
is-superselector("a > c d", "a > b c d")return
false. This also fixes some related
/in a parenthesized list is consistently treated as a plain
/unless it meets the criteria for being treated as division.
sass-convert, ensure that literal
/es are preserved.
Sass 扩展了 CSS3，增加了规则、变量、混入、选择器、继承等等特性。Sass 生成良好格式化的 CSS 代码，易于组织和维护。