Use unicode U+2215 for division

src/buttons.js

@@ -165,7 +165,7 @@ class ClapperElapsedTimeButton extends PopoverButtonBase
 
     setInitialState()
     {
-        this.label = '00∶00/00∶00';
+        this.label = '00∶00∕00∶00';
     }
 
     setFullscreenMode(isFullscreen, isMobileMonitor)

src/controls.js

@@ -146,7 +146,7 @@ class ClapperControls extends Gtk.Box
         value = value || 0;
 
         const elapsed = Misc.getFormattedTime(value, this.showHours)
-            + '/' + this.durationFormatted;
+            + '∕' + this.durationFormatted;
 
         this.elapsedButton.label = elapsed;
     }