diff --git a/css/at-rules.json b/css/at-rules.json
index 8391ba271..afe4a88e6 100644
--- a/css/at-rules.json
+++ b/css/at-rules.json
@@ -340,7 +340,7 @@
     "mdn_url": "https://developer.mozilla.org/docs/Web/CSS/@import"
   },
   "@keyframes": {
-    "syntax": "@keyframes <keyframes-name> {\n  <keyframe-block-list>\n}",
+    "syntax": "@keyframes <keyframes-name> {\n  <qualified-rule-list>\n}",
     "interfaces": [
       "CSSKeyframeRule",
       "CSSKeyframesRule"
diff --git a/css/syntaxes.json b/css/syntaxes.json
index 2466a56cf..a2904cef4 100644
--- a/css/syntaxes.json
+++ b/css/syntaxes.json
@@ -461,11 +461,8 @@
   "keyframe-block": {
     "syntax": "<keyframe-selector># {\n  <declaration-list>\n}"
   },
-  "keyframe-block-list": {
-    "syntax": "<keyframe-block>+"
-  },
   "keyframe-selector": {
-    "syntax": "from | to | <percentage> | <timeline-range-name> <percentage>"
+    "syntax": "from | to | <percentage [0,100]> | <timeline-range-name> <percentage>"
   },
   "keyframes-name": {
     "syntax": "<custom-ident> | <string>"