diff --git a/__tests__/purgecss.test.js b/__tests__/purgecss.test.js
index 1a47c170..657b1ff2 100644
--- a/__tests__/purgecss.test.js
+++ b/__tests__/purgecss.test.js
@@ -317,6 +317,10 @@ describe('special characters, with custom Extractor', () => {
     it('finds tailwind class', () => {
         expect(purgecssResult.includes('md\\:w-1\\/3')).toBe(true)
     })
+
+    it('discards unused class beginning with number', () => {
+        expect(purgecssResult.includes('\\32 -panel')).toBe(false)
+    })
 })
 
 describe('special characters, with custom Extractor as a function', () => {
diff --git a/__tests__/test_examples/special_characters/special_characters.css b/__tests__/test_examples/special_characters/special_characters.css
index 5e467db1..188124c2 100644
--- a/__tests__/test_examples/special_characters/special_characters.css
+++ b/__tests__/test_examples/special_characters/special_characters.css
@@ -9,3 +9,7 @@
 .md\:w-1\/3 {
   color: green;
 }
+
+.\32 -panels {
+  color: red;
+}
diff --git a/src/index.js b/src/index.js
index e2fc5a36..859fbd37 100644
--- a/src/index.js
+++ b/src/index.js
@@ -300,6 +300,10 @@ class Purgecss {
             return
         }
 
+        if (node.parent && node.parent.type === 'atrule' && node.parent.name === 'keyframes') {
+            return
+        }
+
         let keepSelector = true
         node.selector = selectorParser(selectorsParsed => {
             selectorsParsed.walk(selector => {
@@ -316,8 +320,7 @@ class Purgecss {
                     for (const { type, value } of selector.nodes) {
                         if (
                             SELECTOR_STANDARD_TYPES.includes(type) &&
-                            typeof value !== 'undefined' &&
-                            /^\d/g.test(value) === false
+                            typeof value !== 'undefined'
                         ) {
                             selectorsInRule.push(value)
                         } else if (