unocss
diff --git a/‎packages-presets/transformer-directives/src/transform.ts
Lines changed: 8 additions & 2 deletions b/‎packages-presets/transformer-directives/src/transform.ts
Lines changed: 8 additions & 2 deletions
diff --git a/‎test/transformer-directives.test.ts
Lines changed: 22 additions & 0 deletions b/‎test/transformer-directives.test.ts
Lines changed: 22 additions & 0 deletions
@@ -71,10 +71,16 @@ export async function transformDirectives(
 
   await Promise.all(stack)
 
-  // Remove empty blocks
   const oldCode = code.toString()
+  // transformDirectives has recursive behavior, only for the last call
   if (!isHasApply(oldCode)) {
-    const newCode = oldCode.replace(/[^{}]*\{\s*\}\s*/g, '')
+    const newCode = oldCode.replace(/([^{}]+)\{\s*\}\s*/g, (m, selector) => {
+      // Only remove empty rules with valid selectors
+      if (/^[\s\w\-.,#:[\]=*"'>~+^$|()\\]+$/.test(selector.trim()))
+        return ''
+      return m
+    })
+
     if (newCode !== oldCode)
       code.update(0, code.original.length, newCode)
   }
 
@@ -655,6 +655,28 @@ div {
       `)
   })
 
+  it('@apply with empty block comments', async () => {
+    const result = await transform(
+      `
+.aaa {
+  @apply text-blue-500;
+  /* {} empty curly brace in comment will lead to wrong parsing */
+  font-weight: 900;
+}
+      `,
+    )
+    expect(result)
+      .toMatchInlineSnapshot(`
+        ".aaa {
+          --un-text-opacity: 1;
+          color: rgb(59 130 246 / var(--un-text-opacity));
+          /* {} empty curly brace in comment will lead to wrong parsing */
+          font-weight: 900;
+        }
+        "
+      `)
+  })
+
   it('@apply selector group', async () => {
     const result = await transform(
       '.btn { @apply: sgroup:bg-orange }',