Update spa sass, fix timestamp dark mode bug

resources/assets/sass/spa.scss

@@ -392,6 +392,10 @@ span.twitter-typeahead .tt-suggestion:focus {
     font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
 }
 
+.timestamp-overlay-badge {
+    color: var(--dark);
+}
+
 .timeline-status-component {
     .username {
         font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;