scope embiggening

frontend/src/components/dashboard/dashboard.css

@@ -419,7 +419,13 @@
   increase the base font size in fullscreen mode to bump things up to
   accomodate for viewing distance on TVs etc
 */
-.Dashboard.Dashboard--fullscreen { font-size: 1.6em; }
+@media screen and (min-width: 1280px) {
+  .Dashboard.Dashboard--fullscreen { font-size: 1.2em; }
+  /* keep the dashboard header title from being overwhelmingly large */
+  .Dashboard.Dashboard--fullscreen .Header-title-name { font-size: 1em; }
+}
+
+@media screen and (min-width: 1540px) {
+  .Dashboard.Dashboard--fullscreen { font-size: 1.6em; }
 
-/* keep the dashboard header title from being overwhelmingly large */
-.Dashboard.Dashboard--fullscreen .Header-title-name { font-size: 1em; }
+}