diff --git a/Libraries/LibWeb/CSS/Parser/PropertyParsing.cpp b/Libraries/LibWeb/CSS/Parser/PropertyParsing.cpp
index 0172bdb409..c62da16b21 100644
--- a/Libraries/LibWeb/CSS/Parser/PropertyParsing.cpp
+++ b/Libraries/LibWeb/CSS/Parser/PropertyParsing.cpp
@@ -379,38 +379,13 @@ Optional<Parser::PropertyAndValue> Parser::parse_css_value_for_properties(Readon
     return OptionalNone {};
 }
 
-static bool block_contains_var_or_attr(SimpleBlock const& block);
-
-static bool function_contains_var_or_attr(Function const& function)
-{
-    if (function.name.equals_ignoring_ascii_case("var"sv) || function.name.equals_ignoring_ascii_case("attr"sv))
-        return true;
-    for (auto const& token : function.value) {
-        if (token.is_function() && function_contains_var_or_attr(token.function()))
-            return true;
-        if (token.is_block() && block_contains_var_or_attr(token.block()))
-            return true;
-    }
-    return false;
-}
-
-bool block_contains_var_or_attr(SimpleBlock const& block)
-{
-    for (auto const& token : block.value) {
-        if (token.is_function() && function_contains_var_or_attr(token.function()))
-            return true;
-        if (token.is_block() && block_contains_var_or_attr(token.block()))
-            return true;
-    }
-    return false;
-}
-
 Parser::ParseErrorOr<NonnullRefPtr<CSSStyleValue>> Parser::parse_css_value(PropertyID property_id, TokenStream<ComponentValue>& unprocessed_tokens, Optional<String> original_source_text)
 {
     auto context_guard = push_temporary_value_parsing_context(property_id);
 
+    // FIXME: Stop removing whitespace here. It's less helpful than it seems.
     Vector<ComponentValue> component_values;
-    bool contains_var_or_attr = false;
+    bool contains_arbitrary_substitution_function = false;
     bool const property_accepts_custom_ident = property_accepts_type(property_id, ValueType::CustomIdent);
 
     while (unprocessed_tokens.has_next_token()) {
@@ -429,18 +404,18 @@ Parser::ParseErrorOr<NonnullRefPtr<CSSStyleValue>> Parser::parse_css_value(Prope
                 return ParseError::IncludesIgnoredVendorPrefix;
         }
 
-        if (!contains_var_or_attr) {
-            if (token.is_function() && function_contains_var_or_attr(token.function()))
-                contains_var_or_attr = true;
-            else if (token.is_block() && block_contains_var_or_attr(token.block()))
-                contains_var_or_attr = true;
+        if (!contains_arbitrary_substitution_function) {
+            if (token.is_function() && token.function().contains_arbitrary_substitution_function())
+                contains_arbitrary_substitution_function = true;
+            else if (token.is_block() && token.block().contains_arbitrary_substitution_function())
+                contains_arbitrary_substitution_function = true;
         }
 
         component_values.append(token);
     }
 
-    if (property_id == PropertyID::Custom || contains_var_or_attr)
-        return UnresolvedStyleValue::create(move(component_values), contains_var_or_attr, original_source_text);
+    if (property_id == PropertyID::Custom || contains_arbitrary_substitution_function)
+        return UnresolvedStyleValue::create(move(component_values), contains_arbitrary_substitution_function, original_source_text);
 
     if (component_values.is_empty())
         return ParseError::SyntaxError;
diff --git a/Libraries/LibWeb/CSS/Parser/Types.cpp b/Libraries/LibWeb/CSS/Parser/Types.cpp
index 664e71b53a..fac61e738a 100644
--- a/Libraries/LibWeb/CSS/Parser/Types.cpp
+++ b/Libraries/LibWeb/CSS/Parser/Types.cpp
@@ -51,6 +51,17 @@ String SimpleBlock::original_source_text() const
     return builder.to_string_without_validation();
 }
 
+bool SimpleBlock::contains_arbitrary_substitution_function() const
+{
+    for (auto const& component_value : value) {
+        if (component_value.is_function() && component_value.function().contains_arbitrary_substitution_function())
+            return true;
+        if (component_value.is_block() && component_value.block().contains_arbitrary_substitution_function())
+            return true;
+    }
+    return false;
+}
+
 String Function::to_string() const
 {
     StringBuilder builder;
@@ -75,6 +86,19 @@ String Function::original_source_text() const
     return builder.to_string_without_validation();
 }
 
+bool Function::contains_arbitrary_substitution_function() const
+{
+    if (name.equals_ignoring_ascii_case("var"sv) || name.equals_ignoring_ascii_case("attr"sv))
+        return true;
+    for (auto const& component_value : value) {
+        if (component_value.is_function() && component_value.function().contains_arbitrary_substitution_function())
+            return true;
+        if (component_value.is_block() && component_value.block().contains_arbitrary_substitution_function())
+            return true;
+    }
+    return false;
+}
+
 void AtRule::for_each(AtRuleVisitor&& visit_at_rule, QualifiedRuleVisitor&& visit_qualified_rule, DeclarationVisitor&& visit_declaration) const
 {
     for (auto const& child : child_rules_and_lists_of_declarations) {
diff --git a/Libraries/LibWeb/CSS/Parser/Types.h b/Libraries/LibWeb/CSS/Parser/Types.h
index 6813ec6943..285c6174f9 100644
--- a/Libraries/LibWeb/CSS/Parser/Types.h
+++ b/Libraries/LibWeb/CSS/Parser/Types.h
@@ -72,6 +72,7 @@ struct SimpleBlock {
 
     String to_string() const;
     String original_source_text() const;
+    bool contains_arbitrary_substitution_function() const;
 };
 
 // https://drafts.csswg.org/css-syntax/#function
@@ -83,6 +84,7 @@ struct Function {
 
     String to_string() const;
     String original_source_text() const;
+    bool contains_arbitrary_substitution_function() const;
 };
 
 }