refactor: Media queries (#2680)

src/css/_variables.scss

@@ -1,3 +1,4 @@
 @import "open-color/open-color.scss";
 
-$media-query: "(max-width: 600px), (max-height: 500px) and (max-width: 1000px)";
+// keep up to date with is-mobile.tsx
+$is-mobile-query: "(max-width: 600px), (max-height: 500px) and (max-width: 1000px)";

src/css/styles.scss

@@ -441,7 +441,7 @@
     }
   }
 
-  @media #{$media-query} {
+  @media #{$is-mobile-query} {
     aside {
       display: none;
     }