diff --git a/src/browser/css/Parser.zig b/src/browser/css/Parser.zig
index 401baecb..53488d96 100644
--- a/src/browser/css/Parser.zig
+++ b/src/browser/css/Parser.zig
@@ -306,6 +306,7 @@ pub fn parseStylesheet(input: []const u8) RulesIterator {
 pub const RulesIterator = struct {
     input: []const u8,
     stream: TokenStream,
+    has_skipped_at_rule: bool = false,
 
     pub fn init(input: []const u8) RulesIterator {
         return .{
@@ -358,6 +359,7 @@ pub const RulesIterator = struct {
             }
 
             if (peeked.token == .at_keyword) {
+                self.has_skipped_at_rule = true;
                 self.skipAtRule();
                 selector_start = null;
                 selector_end = null;
diff --git a/src/browser/webapi/css/CSSStyleSheet.zig b/src/browser/webapi/css/CSSStyleSheet.zig
index 52dcbf21..00764d15 100644
--- a/src/browser/webapi/css/CSSStyleSheet.zig
+++ b/src/browser/webapi/css/CSSStyleSheet.zig
@@ -76,10 +76,11 @@ pub fn insertRule(self: *CSSStyleSheet, rule: []const u8, maybe_index: ?u32, pag
     const index = maybe_index orelse 0;
     var it = Parser.parseStylesheet(rule);
     const parsed_rule = it.next() orelse {
-        const trimmed = std.mem.trimLeft(u8, rule, &std.ascii.whitespace);
-        if (std.mem.startsWith(u8, trimmed, "@")) {
-            // At-rules (like @keyframes) are currently skipped by the parser.
-            // Returning the index simulates successful insertion without crashing.
+        if (it.has_skipped_at_rule) {
+            // Lightpanda currently skips at-rules (e.g., @keyframes, @media) in its
+            // CSS parser. To prevent JS apps (like Expo/Reanimated) from crashing
+            // during initialization, we simulate a successful insertion by returning
+            // the requested index.
             return index;
         }
         return error.SyntaxError;