diff --git a/components/style/counter_style/mod.rs b/components/style/counter_style/mod.rs
index 772707cbfa83..f27aecc8549e 100644
--- a/components/style/counter_style/mod.rs
+++ b/components/style/counter_style/mod.rs
@@ -22,7 +22,28 @@ use values::CustomIdent;
 
 /// Parse the prelude of an @counter-style rule
 pub fn parse_counter_style_name(input: &mut Parser) -> Result<CustomIdent, ()> {
-    CustomIdent::from_ident(input.expect_ident()?, &["decimal", "none"])
+    macro_rules! predefined {
+        ($($name: expr,)+) => {
+            {
+                ascii_case_insensitive_phf_map! {
+                    // FIXME: use static atoms https://github.com/rust-lang/rust/issues/33156
+                    predefined -> &'static str = {
+                        $(
+                            $name => $name,
+                        )+
+                    }
+                }
+
+                let ident = input.expect_ident()?;
+                if let Some(&lower_cased) = predefined(&ident) {
+                    Ok(CustomIdent(Atom::from(lower_cased)))
+                } else {
+                    CustomIdent::from_ident(ident, &["decimal", "none"])
+                }
+            }
+        }
+    }
+    include!("predefined.rs")
 }
 
 /// Parse the body (inside `{}`) of an @counter-style rule
diff --git a/components/style/counter_style/predefined.rs b/components/style/counter_style/predefined.rs
new file mode 100644
index 000000000000..dee17e903771
--- /dev/null
+++ b/components/style/counter_style/predefined.rs
@@ -0,0 +1,60 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+predefined! {
+    "decimal-leading-zero",
+    "arabic-indic",
+    "armenian",
+    "upper-armenian",
+    "lower-armenian",
+    "bengali",
+    "cambodian",
+    "khmer",
+    "cjk-decimal",
+    "devanagari",
+    "georgian",
+    "gujarati",
+    "gurmukhi",
+    "hebrew",
+    "kannada",
+    "lao",
+    "malayalam",
+    "mongolian",
+    "myanmar",
+    "oriya",
+    "persian",
+    "lower-roman",
+    "upper-roman",
+    "tamil",
+    "telugu",
+    "thai",
+    "tibetan",
+    "lower-alpha",
+    "lower-latin",
+    "upper-alpha",
+    "upper-latin",
+    "cjk-earthly-branch",
+    "cjk-heavenly-stem",
+    "lower-greek",
+    "hiragana",
+    "hiragana-iroha",
+    "katakana",
+    "katakana-iroha",
+    "disc",
+    "circle",
+    "square",
+    "disclosure-open",
+    "disclosure-closed",
+    "japanese-informal",
+    "japanese-formal",
+    "korean-hangul-formal",
+    "korean-hanja-informal",
+    "korean-hanja-formal",
+    "simp-chinese-informal",
+    "simp-chinese-formal",
+    "trad-chinese-informal",
+    "trad-chinese-formal",
+    "cjk-ideographic",
+    "ethiopic-numeric",
+}
diff --git a/components/style/counter_style/update_predefined.py b/components/style/counter_style/update_predefined.py
new file mode 100755
index 000000000000..9e64545b5934
--- /dev/null
+++ b/components/style/counter_style/update_predefined.py
@@ -0,0 +1,35 @@
+#!/usr/bin/env python
+
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+import os.path
+import re
+import urllib
+
+
+def main(filename):
+    names = [
+        re.search('>([^>]+)(</dfn>|<a class="self-link")', line).group(1)
+        for line in urllib.urlopen("https://drafts.csswg.org/css-counter-styles/")
+        if 'data-dfn-for="<counter-style-name>"' in line
+        or 'data-dfn-for="<counter-style>"' in line
+    ]
+    with open(filename, "wb") as f:
+        f.write("""\
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+predefined! {
+""")
+        for name in names:
+            # FIXME https://github.com/w3c/csswg-drafts/issues/1285
+            if name == 'decimal':
+                continue
+            f.write('    "%s",\n' % name)
+        f.write('}\n')
+
+if __name__ == "__main__":
+    main(os.path.join(os.path.dirname(__file__), "predefined.rs"))