adding a11y-focused sr-only and sr-only-focusable utilities

1 files changed, 34 insertions, 0 deletions

diff --git a/scss/_mixins.scss b/scss/_mixins.scss
index d9c1034f4..c7c453429 100644
--- a/scss/_mixins.scss
+++ b/scss/_mixins.scss
@@ -24,3 +24,37 @@
       -ms-transform: scale($horiz, $vert);
           transform: scale($horiz, $vert);
 }
+
+
+// Only display content to screen readers. À la Bootstrap 4.
+//
+// See: http://a11yproject.com/posts/how-to-hide-content/
+
+@mixin sr-only {
+  position: absolute;
+  width: 1px;
+  height: 1px;
+  padding: 0;
+  margin: -1px;
+  overflow: hidden;
+  clip: rect(0,0,0,0);
+  border: 0;
+}
+
+// Use in conjunction with .sr-only to only display content when it's focused.
+//
+// Useful for "Skip to main content" links; see http://www.w3.org/TR/2013/NOTE-WCAG20-TECHS-20130905/G1
+//
+// Credit: HTML5 Boilerplate
+
+@mixin sr-only-focusable {
+  &:active,
+  &:focus {
+    position: static;
+    width: auto;
+    height: auto;
+    margin: 0;
+    overflow: visible;
+    clip: auto;
+  }
+}