Don't prefer STIXGeneral over the default font

.github/workflows/cypress.yaml

@@ -92,6 +92,12 @@ jobs:
             #      # Run 4 instances in Parallel
             #      runner: [1, 2, 3, 4]
         steps:
+            - uses: tecolicom/actions-use-apt-tools@v1
+              with:
+                  # Our test suite includes some screenshot tests with unusual diacritics, which are
+                  # supposed to be covered by STIXGeneral.
+                  tools: fonts-stix
+
             - uses: actions/checkout@v3
               with:
                   # XXX: We're checking out untrusted code in a secure context

cypress/e2e/polls/polls.spec.ts

@@ -115,7 +115,10 @@ describe("Polls", () => {
 
         const pollParams = {
             title: "Does the polls feature work?",
-            options: ["Yes", "No", "Maybe"],
+            // Since we're going to take a screenshot anyways, we include some
+            // non-ASCII characters here to stress test the app's font config
+            // while we're at it.
+            options: ["Yes", "Noo⃐o⃑o⃩o⃪o⃫o⃬o⃭o⃮o⃯", "のらねこ Maybe?"],
         };
         createPoll(pollParams);
 

res/themes/legacy-light/css/_legacy-light.pcss

@@ -4,17 +4,20 @@
    Arial empirically gets it right, hence prioritising Arial here.
    We also include STIXGeneral explicitly to support a wider range
    of combining diacritics (Chrome fails without it, as per
-   https://bugs.chromium.org/p/chromium/issues/detail?id=1328898) */
+   https://bugs.chromium.org/p/chromium/issues/detail?id=1328898).
+   We should never actively *prefer* STIXGeneral over the default font though,
+   since it looks pretty rough and implements some non-LGC scripts only
+   partially, making, for example, Japanese text look patchy and sad. */
 /* We fall through to Twemoji for emoji rather than falling through
    to native Emoji fonts (if any) to ensure cross-browser consistency */
 /* Noto Color Emoji contains digits, in fixed-width, therefore causing
    digits in flowed text to stand out.
    TODO: Consider putting all emoji fonts to the end rather than the front. */
-$font-family: "Nunito", "Twemoji", "Apple Color Emoji", "Segoe UI Emoji", "STIXGeneral", "Arial", "Helvetica",
-    sans-serif, "Noto Color Emoji";
+$font-family: "Nunito", "Twemoji", "Apple Color Emoji", "Segoe UI Emoji", "Arial", "Helvetica", sans-serif,
+    "STIXGeneral", "Noto Color Emoji";
 
-$monospace-font-family: "Inconsolata", "Twemoji", "Apple Color Emoji", "Segoe UI Emoji", "STIXGeneral", "Courier",
-    monospace, "Noto Color Emoji";
+$monospace-font-family: "Inconsolata", "Twemoji", "Apple Color Emoji", "Segoe UI Emoji", "Courier", monospace,
+    "STIXGeneral", "Noto Color Emoji";
 
 /* unified palette */
 /* try to use these colors when possible */

res/themes/light/css/_light.pcss

@@ -4,17 +4,20 @@
    Arial empirically gets it right, hence prioritising Arial here.
    We also include STIXGeneral explicitly to support a wider range
    of combining diacritics (Chrome fails without it, as per
-   https://bugs.chromium.org/p/chromium/issues/detail?id=1328898) */
+   https://bugs.chromium.org/p/chromium/issues/detail?id=1328898).
+   We should never actively *prefer* STIXGeneral over the default font though,
+   since it looks pretty rough and implements some non-LGC scripts only
+   partially, making, for example, Japanese text look patchy and sad. */
 /* We fall through to Twemoji for emoji rather than falling through
    to native Emoji fonts (if any) to ensure cross-browser consistency */
 /* Noto Color Emoji contains digits, in fixed-width, therefore causing
    digits in flowed text to stand out.
    TODO: Consider putting all emoji fonts to the end rather than the front. */
-$font-family: "Inter", "Twemoji", "Apple Color Emoji", "Segoe UI Emoji", "STIXGeneral", "Arial", "Helvetica", sans-serif,
+$font-family: "Inter", "Twemoji", "Apple Color Emoji", "Segoe UI Emoji", "Arial", "Helvetica", sans-serif, "STIXGeneral",
     "Noto Color Emoji";
 
-$monospace-font-family: "Inconsolata", "Twemoji", "Apple Color Emoji", "Segoe UI Emoji", "STIXGeneral", "Courier",
-    monospace, "Noto Color Emoji";
+$monospace-font-family: "Inconsolata", "Twemoji", "Apple Color Emoji", "Segoe UI Emoji", "Courier", monospace,
+    "STIXGeneral", "Noto Color Emoji";
 
 /* Colors from Figma Compound https://www.figma.com/file/X4XTH9iS2KGJ2wFKDqkyed/Compound?node-id=559%3A120 */
 /* ******************** */