Pushed to version 0.1.8. Details in changelog. (Makefile, FontAwesome, sass)

assets/sass/lib/bourbon/functions/_is-size.scss

@@ -0,0 +1,13 @@
+@charset "UTF-8";
+
+/// Checks for a valid CSS size.
+///
+/// @param {String} $value
+///
+/// @require {function} contains
+/// @require {function} is-length
+
+@function is-size($value) {
+  @return is-length($value)
+          or contains("fill" "fit-content" "min-content" "max-content", $value);
+}