diff --git a/src/librustdoc/html/static/rustdoc.css b/src/librustdoc/html/static/rustdoc.css
index d7f4674908c58..7efe7e1ae3eb3 100644
--- a/src/librustdoc/html/static/rustdoc.css
+++ b/src/librustdoc/html/static/rustdoc.css
@@ -920,6 +920,12 @@ span.since {
 	border-color: transparent black transparent transparent;
 }
 
+.important-traits .tooltip .tooltiptext {
+	background-color: white;
+	color: black;
+	border: 1px solid #000;
+}
+
 pre.rust {
 	position: relative;
 }