Use :focus-visible instead of :focus for focus markers

In this way, after the user clicked with a pointer and moved that
pointer away, the focus marker will no longer show a focused style.

As Safari remains the only major browser engine that does not support
:focus-visible, a fallback to :focus is used if there is no browser
support for :focus-visible.

https://developer.mozilla.org/en-US/docs/Web/CSS/:focus-visible

src/components/reply_button/reply_button.vue

@@ -67,11 +67,12 @@
       color: var(--cBlue, $fallback--cBlue);
     }
 
-    .focus-marker {
+    .focus-marker,
+    &:focus:not(:focus-visible):not(:hover) .focus-marker {
       visibility: hidden;
     }
 
-    &:hover, &:focus {
+    &:hover, &:focus, &:focus-visible {
       .focus-marker {
         visibility: visible;
       }