feat: add katex math typesetting

assets/scss/app.scss

@@ -10,6 +10,9 @@
 /** Import highlight.js */
 // @import "highlight.js/scss/dracula";
 
+/** Import KaTeX */
+@import "katex/dist/katex";
+
 /** Import theme styles */
 @import "common/fonts";
 @import "common/global";

assets/scss/common/_global.scss

@@ -223,3 +223,7 @@ body {
   -webkit-text-fill-color: transparent;
   -moz-text-fill-color: transparent;
 }
+
+.katex {
+  font-size: $font-size-md;
+}