space is not mandatory in attricute selector parsing when a modifier is expected, per https://www.w3.org/TR/2026/WD-selectors-4-20260122/#typedef-attribute-selector

Fixes #450

Author: ylafon

org/w3c/css/parser/analyzer/CssParser.java

@@ -5634,7 +5634,6 @@ final public CssSelectors subclass_selector(CssSelectors selector) throws ParseE
       if (jj_2_19(2)) {
         label_148:
         while (true) {
-          jj_consume_token(S);
           switch ((jj_ntk==-1)?jj_ntk_f():jj_ntk) {
           case S:{
             ;
@@ -5644,6 +5643,7 @@ final public CssSelectors subclass_selector(CssSelectors selector) throws ParseE
             jj_la1[216] = jj_gen;
             break label_148;
           }
+          jj_consume_token(S);
         }
         mod = ident();
       } else {
@@ -11322,7 +11322,6 @@ private boolean jj_3R_layer_1850_43_242()
   private boolean jj_3_19()
  {
     Token xsp;
-    if (jj_scan_token(21)) return true;
     while (true) {
       xsp = jj_scanpos;
       if (jj_scan_token(21)) { jj_scanpos = xsp; break; }

org/w3c/css/parser/analyzer/CssParser.jj

@@ -2642,7 +2642,7 @@ void attribute_selector(CssSelectors s) :
 	   | val=<STRING> 
 	       { val.image = convertStringIndex(val.image, 1, val.image.length() -1, false);} 
 	   ) 
-	   ( LOOKAHEAD(2) ( <S> )+ mod=ident() )? ( <S> )*  )?
+	   ( LOOKAHEAD(2) ( <S> )* mod=ident() )? ( <S> )*  )?
     <RBRACKET>
       {
 	if (ac.getCssVersion() == CssVersion.CSS1) {