diff --git a/components/style/values/computed/counters.rs b/components/style/values/computed/counters.rs
index b030768301b..0e3510b8265 100644
--- a/components/style/values/computed/counters.rs
+++ b/components/style/values/computed/counters.rs
@@ -9,8 +9,7 @@ use computed_values::list_style_type::T as ListStyleType;
 use cssparser::{Parser, Token};
 use parser::{Parse, ParserContext};
 use selectors::parser::SelectorParseErrorKind;
-use std::fmt::{self, Write};
-use style_traits::{CssWriter, ParseError, StyleParseErrorKind, ToCss};
+use style_traits::{ParseError, StyleParseErrorKind};
 use values::CustomIdent;
 #[cfg(feature = "gecko")]
 use values::generics::CounterStyleOrNone;
@@ -148,39 +147,3 @@ impl Parse for Content {
         Ok(Content::Items(content.into_boxed_slice()))
     }
 }
-
-impl ToCss for ContentItem {
-    fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result
-        where W: Write,
-    {
-        match *self {
-            ContentItem::String(ref s) => s.to_css(dest),
-            ContentItem::Counter(ref s, ref counter_style) => {
-                dest.write_str("counter(")?;
-                s.to_css(dest)?;
-                dest.write_str(", ")?;
-                counter_style.to_css(dest)?;
-                dest.write_str(")")
-            }
-            ContentItem::Counters(ref s, ref separator, ref counter_style) => {
-                dest.write_str("counters(")?;
-                s.to_css(dest)?;
-                dest.write_str(", ")?;
-                separator.to_css(dest)?;
-                dest.write_str(", ")?;
-                counter_style.to_css(dest)?;
-                dest.write_str(")")
-            }
-            ContentItem::OpenQuote => dest.write_str("open-quote"),
-            ContentItem::CloseQuote => dest.write_str("close-quote"),
-            ContentItem::NoOpenQuote => dest.write_str("no-open-quote"),
-            ContentItem::NoCloseQuote => dest.write_str("no-close-quote"),
-            #[cfg(feature = "gecko")]
-            ContentItem::Attr(ref attr) => {
-                attr.to_css(dest)
-            }
-            #[cfg(feature = "gecko")]
-            ContentItem::Url(ref url) => url.to_css(dest),
-        }
-    }
-}
diff --git a/components/style/values/specified/counters.rs b/components/style/values/specified/counters.rs
index a420e02f747..9460f3965cf 100644
--- a/components/style/values/specified/counters.rs
+++ b/components/style/values/specified/counters.rs
@@ -97,13 +97,15 @@ pub enum Content {
 }
 
 /// Items for the `content` property.
-#[derive(Clone, Debug, Eq, MallocSizeOf, PartialEq, ToComputedValue)]
+#[derive(Clone, Debug, Eq, MallocSizeOf, PartialEq, ToComputedValue, ToCss)]
 pub enum ContentItem {
     /// Literal string content.
     String(Box<str>),
     /// `counter(name, style)`.
+    #[css(comma, function)]
     Counter(CustomIdent, CounterStyleType),
     /// `counters(name, separator, style)`.
+    #[css(comma, function)]
     Counters(CustomIdent, Box<str>, CounterStyleType),
     /// `open-quote`.
     OpenQuote,