Hide an element to all devices except screen readers with .sr-only. Combine .sr-only with .sr-only-focusable to show the element again when it’s focused (e.g. by a keyboard-only user). Can also be used as mixins.
<a class="sr-only sr-only-focusable" href="#content">Skip to main content</a>
// Usage as a mixin
.skip-navigation {
@include sr-only;
@include sr-only-focusable;
}