add sass/scratch.scss and associated sass files

Resources/public/sass/contrib/bourbon/css3/_selection.scss

@@ -0,0 +1,42 @@
+@charset "UTF-8";
+
+/// Outputs the spec and prefixed versions of the `::selection` pseudo-element.
+///
+/// @param {Bool} $current-selector [false]
+///   If set to `true`, it takes the current element into consideration.
+///
+/// @example scss - Usage
+///   .element {
+///     @include selection(true) {
+///       background-color: #ffbb52;
+///     }
+///   }
+///
+/// @example css - CSS Output
+///   .element::-moz-selection {
+///     background-color: #ffbb52;
+///   }
+///
+///   .element::selection {
+///     background-color: #ffbb52;
+///   }
+
+@mixin selection($current-selector: false) {
+  @if $current-selector {
+    &::-moz-selection {
+      @content;
+    }
+
+    &::selection {
+      @content;
+    }
+  } @else {
+    ::-moz-selection {
+      @content;
+    }
+
+    ::selection {
+      @content;
+    }
+  }
+}