split up SCSS files

assets/sass/abstracts/_functions.scss

@@ -0,0 +1,13 @@
+@charset "UTF-8";
+
+// Gradient hack to get our custom underline to wrap:
+// https://www.dannyguo.com/blog/animated-multiline-link-underlines-with-css/
+@function underline-hack($color) {
+  // Calculate lighter underline color compared to text color by
+  // mix()'ing with background (#fff) to give the impression of
+  // opacity but with MUCH better compatibility.
+  $color-opaque: mix($color, $color-background, $link-opacity);
+
+  // Return non-gradient linear-gradient():
+  @return linear-gradient($color-opaque, $color-opaque);
+}