Add visually-hidden mixing

src/styles/mixins/visually-hidden.scss

@@ -0,0 +1,9 @@
+@mixin visually-hidden {
+  clip: rect(0 0 0 0);
+  clip-path: inset(50%);
+  height: 1px;
+  overflow: hidden;
+  position: absolute;
+  white-space: nowrap;
+  width: 1px;
+}