Don't use custom built-in elements because they are not supported in webkit

src/index.js

@@ -11,7 +11,6 @@ const mapPlaceholder = document.querySelector('.map-placeholder'),
   distanceOutput = document.getElementById('status'),
   proneToggle = document.getElementById('toggle-prone-counter'),
   contentVisToggleEl = document.querySelector('#content input[type="checkbox"].visible'),
-  // fileName = localStorage.getItem('map') || (env === 'test' ? 'test_map' : 'map1'),
   fileName = localStorage.getItem('map') || 'scenario-side_show',
   map = scenarios[fileName]?.hashed || `assets/images/${fileName}.svg`,
   fileInputEl = document.querySelector('input[type="file"]'),