diff --git a/lib/spoom/coverage/d3.rb b/lib/spoom/coverage/d3.rb
index 455a0715..76b7155c 100644
--- a/lib/spoom/coverage/d3.rb
+++ b/lib/spoom/coverage/d3.rb
@@ -12,7 +12,6 @@ module D3
       COLOR_FALSE = "#db4437"
       COLOR_TRUE = "#0f9d58"
       COLOR_STRICT = "#0a7340"
-      COLOR_STRONG = "#064828"
 
       class << self
         extend T::Sig