diff --git a/src/katex.less b/src/katex.less
index 546dc7c8..7775f418 100644
--- a/src/katex.less
+++ b/src/katex.less
@@ -542,14 +542,10 @@
         padding: 0 0.3em 0 0.3em;      // \fboxsep = 3pt
     }
 
-    .fbox {
-        box-sizing: border-box;
-        border: 0.04em solid black;   // \fboxrule = 0.4pt
-    }
-
+    .fbox,
     .fcolorbox {
         box-sizing: border-box;
-        border: 0.04em solid;   // \fboxrule = 0.4pt
+        border: 0.04em solid;         // \fboxrule = 0.4pt
     }
 
     .cancel-pad {