Invert the SVG in dark mode

Author: jvns

assets/sass/cheat-sheet.scss

@@ -1,13 +1,5 @@
 @import "variables";
 
-:root {
-  --svg-bg: transparent;
-}
-
-:root[data-theme="dark"] {
-  --svg-bg: #777;
-}
-
 .cheat-sheet {
   font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
 
@@ -32,7 +24,6 @@
       border-radius: 5px;
       padding: 5px;
       box-sizing: border-box;
-      background: var(--svg-bg);
     }
 
     h3 {

assets/sass/dark-mode.css

@@ -152,6 +152,10 @@
             #l10n-versions-dropdown footer a {
                 color: #6969dd;
             }
+
+            .cheat-sheet svg {
+                filter: invert(60%);
+            }
         }
     }