apply monospace font correctly

res/themes/light/css/_light.scss

@@ -7,6 +7,10 @@
    to native Emoji fonts (if any) to ensure cross-browser consistency */
 $font-family: Nunito, Arial, Helvetica, Sans-Serif, 'Twemoji Mozilla';
 
+// XXX: In theory this should be Fira, but it's a bit ugly.
+// TODO: make it consistent cross-browser
+$monospace-font-family: Consolas, 'Liberation Mono', Menlo, Courier, monospace, 'Twemoji Mozilla';
+
 // unified palette
 // try to use these colors when possible
 $accent-color: #03b381;