Fix CJK fonts again and misc. font issues (#14575)

* Push system-ui further down the stack, fix #12966

* Fix Firefox showing U+300x in emoji font and more

* Revert emoji font and fix long-standing Safari bug

* Exclude Safari emoji fix above 1.25x zoom

* Minor correctness/typo fix, affects only legacy platforms

* Emoji consistency for monospace (e.g. EasyMDE)

* Override paradigm; macOS/iOS-specific metric fix

* Move whitespace fix to font-face

* Handle metric calculation errors with Firefox

* One last workaround for aliased fonts in Linux

1 files changed, 13 insertions, 0 deletions

diff --git a/web_src/js/utils.js b/web_src/js/utils.js
index fc65644c7b..bc84745066 100644
--- a/web_src/js/utils.js
+++ b/web_src/js/utils.js
@@ -28,3 +28,16 @@ export function uniq(arr) {
 export function stripTags(text) {
   return text.replace(/<[^>]*>?/gm, '');
 }
+
+// searches the inclusive range [minValue, maxValue].
+// credits: https://matthiasott.com/notes/write-your-media-queries-in-pixels-not-ems
+export function mqBinarySearch(feature, minValue, maxValue, step, unit) {
+  if (maxValue - minValue < step) {
+    return minValue;
+  }
+  const mid = Math.ceil((minValue + maxValue) / 2 / step) * step;
+  if (matchMedia(`screen and (min-${feature}:${mid}${unit})`).matches) {
+    return mqBinarySearch(feature, mid, maxValue, step, unit); // feature is >= mid
+  }
+  return mqBinarySearch(feature, minValue, mid - step, step, unit); // feature is < mid
+}