WIP: Add loading dots spinner

scss/_spinners.scss

@@ -83,3 +83,36 @@
     }
   }
 }
+
+//
+// Moving dots
+//
+
+// scss-docs-start spinner-dots-keyframes
+@keyframes spinner-dots {
+  0% {
+    opacity: 1;
+  }
+  50%,
+  100% {
+    opacity: .3;
+  }
+}
+// scss-docs-end spinner-dots-keyframes
+
+.spinner-dots {
+  user-select: none;
+
+  > circle:first-of-type,
+  > circle:nth-of-type(2),
+  > circle:last-of-type {
+    fill: currentcolor;
+    animation: spinner-dots .75s infinite ease-in-out alternate;
+  }
+  > circle:nth-of-type(2) {
+    animation-delay: .25s;
+  }
+  > circle:last-of-type {
+    animation-delay: .5s;
+  }
+}