diff --git a/src/browser/tests/document/query_selector.html b/src/browser/tests/document/query_selector.html
index 91675b82..b333069e 100644
--- a/src/browser/tests/document/query_selector.html
+++ b/src/browser/tests/document/query_selector.html
@@ -270,3 +270,36 @@
   testing.expectEqual('rect', document.querySelector('svg g rect').tagName);
 }
 </script>
+
+<script id=special>
+  testing.expectEqual(null, document.querySelector('\\'));
+
+  testing.expectEqual(null, document.querySelector('div\\'));
+  testing.expectEqual(null, document.querySelector('.test-class\\'));
+  testing.expectEqual(null, document.querySelector('#byId\\'));
+</script>
+
+<div class="café">Non-ASCII class 1</div>
+<div class="日本語">Non-ASCII class 2</div>
+<span id="niño">Non-ASCII ID 1</span>
+<p id="🎨">Non-ASCII ID 2</p>
+
+<script id=nonAsciiSelectors>
+  testing.expectEqual('Non-ASCII class 1', document.querySelector('.café').textContent);
+  testing.expectEqual('Non-ASCII class 2', document.querySelector('.日本語').textContent);
+
+  testing.expectEqual('Non-ASCII ID 1', document.querySelector('#niño').textContent);
+  testing.expectEqual('Non-ASCII ID 2', document.querySelector('#🎨').textContent);
+
+  testing.expectEqual('Non-ASCII class 1', document.querySelector('div.café').textContent);
+  testing.expectEqual('Non-ASCII ID 1', document.querySelector('span#niño').textContent);
+</script>
+
+<span id=".,:!">Punctuation test</span>
+
+<script id=escapedPunctuation>
+{
+  // Test escaped punctuation in ID selectors
+  testing.expectEqual('Punctuation test', document.querySelector('#\\.\\,\\:\\!').textContent);
+}
+</script>
diff --git a/src/browser/webapi/selector/Parser.zig b/src/browser/webapi/selector/Parser.zig
index a594f66f..e188c4e7 100644
--- a/src/browser/webapi/selector/Parser.zig
+++ b/src/browser/webapi/selector/Parser.zig
@@ -49,29 +49,71 @@ const ParseError = error{
     StringTooLarge,
 };
 
+// CSS Syntax preprocessing: normalize line endings (CRLF → LF, CR → LF)
+// https://drafts.csswg.org/css-syntax/#input-preprocessing
+fn preprocessInput(arena: Allocator, input: []const u8) ![]const u8 {
+    var i = std.mem.indexOfScalar(u8, input, '\r') orelse return input;
+
+    var result = try std.ArrayList(u8).initCapacity(arena, input.len);
+    result.appendSliceAssumeCapacity(input[0..i]);
+
+    while (i < input.len) {
+        const c = input[i];
+        if (c == '\r') {
+            result.appendAssumeCapacity('\n');
+            i += 1;
+            if (i < input.len and input[i] == '\n') {
+                i += 1;
+            }
+        } else {
+            result.appendAssumeCapacity(c);
+            i += 1;
+        }
+    }
+
+    return result.items;
+}
+
 pub fn parseList(arena: Allocator, input: []const u8, page: *Page) ParseError![]const Selector.Selector {
+    // Preprocess input to normalize line endings
+    const preprocessed = try preprocessInput(arena, input);
+
     var selectors: std.ArrayList(Selector.Selector) = .empty;
 
-    var remaining = input;
+    var remaining = preprocessed;
     while (true) {
         const trimmed = std.mem.trimLeft(u8, remaining, &std.ascii.whitespace);
         if (trimmed.len == 0) break;
 
         var comma_pos: usize = trimmed.len;
         var depth: usize = 0;
-        for (trimmed, 0..) |c, i| {
+        var i: usize = 0;
+        while (i < trimmed.len) {
+            const c = trimmed[i];
             switch (c) {
-                '(' => depth += 1,
+                '\\' => {
+                    // Skip escape sequence (backslash + next character)
+                    i += 1;
+                    if (i < trimmed.len) i += 1;
+                },
+                '(' => {
+                    depth += 1;
+                    i += 1;
+                },
                 ')' => {
                     if (depth > 0) depth -= 1;
+                    i += 1;
                 },
                 ',' => {
                     if (depth == 0) {
                         comma_pos = i;
                         break;
                     }
+                    i += 1;
+                },
+                else => {
+                    i += 1;
                 },
-                else => {},
             }
         }
 
@@ -237,8 +279,9 @@ fn parsePart(self: *Parser, arena: Allocator, page: *Page) !Part {
         },
         '[' => .{ .attribute = try self.attribute(arena, page) },
         ':' => .{ .pseudo_class = try self.pseudoClass(arena, page) },
-        'a'...'z', 'A'...'Z', '_' => blk: {
-            const tag_name = try self.tag();
+        'a'...'z', 'A'...'Z', '_', '\\', 0x80...0xFF => blk: {
+            // Use parseIdentifier for full escape support
+            const tag_name = try self.parseIdentifier(arena, error.InvalidTagSelector);
             if (tag_name.len > 256) {
                 return error.InvalidTagSelector;
             }