LibWeb: Add basic implementation of @page

This doesn't support selectors, and the only descriptors for now are for
margins.

Libraries/LibWeb/CMakeLists.txt

@@ -84,6 +84,8 @@ set(SOURCES
     CSS/CSSNamespaceRule.cpp
     CSS/CSSNestedDeclarations.cpp
     CSS/CSSNumericType.cpp
+    CSS/CSSPageRule.cpp
+    CSS/CSSPageDescriptors.cpp
     CSS/CSSPropertyRule.cpp
     CSS/CSSRule.cpp
     CSS/CSSRuleList.cpp

Libraries/LibWeb/CSS/CSSPageDescriptors.cpp

@@ -0,0 +1,122 @@
+/*
+ * Copyright (c) 2025, Sam Atkins <sam@ladybird.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibWeb/Bindings/CSSPageDescriptorsPrototype.h>
+#include <LibWeb/CSS/CSSPageDescriptors.h>
+
+namespace Web::CSS {
+
+GC_DEFINE_ALLOCATOR(CSSPageDescriptors);
+
+GC::Ref<CSSPageDescriptors> CSSPageDescriptors::create(JS::Realm& realm, Vector<Descriptor> descriptors)
+{
+    return realm.create<CSSPageDescriptors>(realm, move(descriptors));
+}
+
+CSSPageDescriptors::CSSPageDescriptors(JS::Realm& realm, Vector<Descriptor> descriptors)
+    : CSSDescriptors(realm, AtRuleID::Page, move(descriptors))
+{
+}
+
+CSSPageDescriptors::~CSSPageDescriptors() = default;
+
+void CSSPageDescriptors::initialize(JS::Realm& realm)
+{
+    WEB_SET_PROTOTYPE_FOR_INTERFACE(CSSPageDescriptors);
+    Base::initialize(realm);
+}
+
+WebIDL::ExceptionOr<void> CSSPageDescriptors::set_margin(StringView value)
+{
+    return set_property("margin"sv, value, ""sv);
+}
+
+String CSSPageDescriptors::margin() const
+{
+    return get_property_value("margin"sv);
+}
+
+WebIDL::ExceptionOr<void> CSSPageDescriptors::set_margin_top(StringView value)
+{
+    return set_property("margin-top"sv, value, ""sv);
+}
+
+String CSSPageDescriptors::margin_top() const
+{
+    return get_property_value("margin-top"sv);
+}
+
+WebIDL::ExceptionOr<void> CSSPageDescriptors::set_margin_right(StringView value)
+{
+    return set_property("margin-right"sv, value, ""sv);
+}
+
+String CSSPageDescriptors::margin_right() const
+{
+    return get_property_value("margin-right"sv);
+}
+
+WebIDL::ExceptionOr<void> CSSPageDescriptors::set_margin_bottom(StringView value)
+{
+    return set_property("margin-bottom"sv, value, ""sv);
+}
+
+String CSSPageDescriptors::margin_bottom() const
+{
+    return get_property_value("margin-bottom"sv);
+}
+
+WebIDL::ExceptionOr<void> CSSPageDescriptors::set_margin_left(StringView value)
+{
+    return set_property("margin-left"sv, value, ""sv);
+}
+
+String CSSPageDescriptors::margin_left() const
+{
+    return get_property_value("margin-left"sv);
+}
+
+WebIDL::ExceptionOr<void> CSSPageDescriptors::set_size(StringView value)
+{
+    return set_property("size"sv, value, ""sv);
+}
+
+String CSSPageDescriptors::size() const
+{
+    return get_property_value("size"sv);
+}
+
+WebIDL::ExceptionOr<void> CSSPageDescriptors::set_page_orientation(StringView value)
+{
+    return set_property("page-orientation"sv, value, ""sv);
+}
+
+String CSSPageDescriptors::page_orientation() const
+{
+    return get_property_value("page-orientation"sv);
+}
+
+WebIDL::ExceptionOr<void> CSSPageDescriptors::set_marks(StringView value)
+{
+    return set_property("marks"sv, value, ""sv);
+}
+
+String CSSPageDescriptors::marks() const
+{
+    return get_property_value("marks"sv);
+}
+
+WebIDL::ExceptionOr<void> CSSPageDescriptors::set_bleed(StringView value)
+{
+    return set_property("bleed"sv, value, ""sv);
+}
+
+String CSSPageDescriptors::bleed() const
+{
+    return get_property_value("bleed"sv);
+}
+
+}

Libraries/LibWeb/CSS/CSSPageDescriptors.h

@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2025, Sam Atkins <sam@ladybird.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <LibWeb/CSS/CSSDescriptors.h>
+
+namespace Web::CSS {
+
+// https://drafts.csswg.org/cssom/#csspagedescriptors
+class CSSPageDescriptors final : public CSSDescriptors {
+    WEB_PLATFORM_OBJECT(CSSPageDescriptors, CSSDescriptors);
+    GC_DECLARE_ALLOCATOR(CSSPageDescriptors);
+
+public:
+    [[nodiscard]] static GC::Ref<CSSPageDescriptors> create(JS::Realm&, Vector<Descriptor>);
+
+    virtual ~CSSPageDescriptors() override;
+
+    virtual void initialize(JS::Realm&) override;
+
+    WebIDL::ExceptionOr<void> set_margin(StringView value);
+    String margin() const;
+
+    WebIDL::ExceptionOr<void> set_margin_top(StringView value);
+    String margin_top() const;
+
+    WebIDL::ExceptionOr<void> set_margin_right(StringView value);
+    String margin_right() const;
+
+    WebIDL::ExceptionOr<void> set_margin_bottom(StringView value);
+    String margin_bottom() const;
+
+    WebIDL::ExceptionOr<void> set_margin_left(StringView value);
+    String margin_left() const;
+
+    WebIDL::ExceptionOr<void> set_size(StringView value);
+    String size() const;
+
+    WebIDL::ExceptionOr<void> set_page_orientation(StringView value);
+    String page_orientation() const;
+
+    WebIDL::ExceptionOr<void> set_marks(StringView value);
+    String marks() const;
+
+    WebIDL::ExceptionOr<void> set_bleed(StringView value);
+    String bleed() const;
+
+private:
+    CSSPageDescriptors(JS::Realm&, Vector<Descriptor>);
+};
+
+}

Libraries/LibWeb/CSS/CSSPageDescriptors.idl

@@ -0,0 +1,20 @@
+#import <CSS/CSSStyleDeclaration.idl>
+
+// https://drafts.csswg.org/cssom/#csspagedescriptors
+[Exposed=Window]
+interface CSSPageDescriptors : CSSStyleDeclaration {
+    [LegacyNullToEmptyString] attribute CSSOMString margin;
+    [LegacyNullToEmptyString, AttributeCallbackName=margin_top_regular, ImplementedAs=margin_top] attribute CSSOMString marginTop;
+    [LegacyNullToEmptyString, AttributeCallbackName=margin_right_regular, ImplementedAs=margin_right] attribute CSSOMString marginRight;
+    [LegacyNullToEmptyString, AttributeCallbackName=margin_bottom_regular, ImplementedAs=margin_bottom] attribute CSSOMString marginBottom;
+    [LegacyNullToEmptyString, AttributeCallbackName=margin_left_regular, ImplementedAs=margin_left] attribute CSSOMString marginLeft;
+    [LegacyNullToEmptyString, AttributeCallbackName=margin_top_dashed, ImplementedAs=margin_top] attribute CSSOMString margin-top;
+    [LegacyNullToEmptyString, AttributeCallbackName=margin_right_dashed, ImplementedAs=margin_right] attribute CSSOMString margin-right;
+    [LegacyNullToEmptyString, AttributeCallbackName=margin_bottom_dashed, ImplementedAs=margin_bottom] attribute CSSOMString margin-bottom;
+    [LegacyNullToEmptyString, AttributeCallbackName=margin_left_dashed, ImplementedAs=margin_left] attribute CSSOMString margin-left;
+    [LegacyNullToEmptyString] attribute CSSOMString size;
+    [LegacyNullToEmptyString, AttributeCallbackName=page_orientation_regular, ImplementedAs=page_orientation] attribute CSSOMString pageOrientation;
+    [LegacyNullToEmptyString, AttributeCallbackName=page_orientation_dashed, ImplementedAs=page_orientation] attribute CSSOMString page-orientation;
+    [LegacyNullToEmptyString] attribute CSSOMString marks;
+    [LegacyNullToEmptyString] attribute CSSOMString bleed;
+};

Libraries/LibWeb/CSS/CSSPageRule.cpp

@@ -0,0 +1,80 @@
+/*
+ * Copyright (c) 2025, Sam Atkins <sam@ladybird.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibWeb/Bindings/CSSPageRulePrototype.h>
+#include <LibWeb/Bindings/Intrinsics.h>
+#include <LibWeb/CSS/CSSPageRule.h>
+#include <LibWeb/CSS/DescriptorID.h>
+#include <LibWeb/CSS/Serialize.h>
+#include <LibWeb/WebIDL/ExceptionOr.h>
+
+namespace Web::CSS {
+
+GC_DEFINE_ALLOCATOR(CSSPageRule);
+
+GC::Ref<CSSPageRule> CSSPageRule::create(JS::Realm& realm, SelectorList&& selectors, GC::Ref<CSSPageDescriptors> style, CSSRuleList& rules)
+{
+    return realm.create<CSSPageRule>(realm, move(selectors), style, rules);
+}
+
+CSSPageRule::CSSPageRule(JS::Realm& realm, SelectorList&& selectors, GC::Ref<CSSPageDescriptors> style, CSSRuleList& rules)
+    : CSSGroupingRule(realm, rules, Type::Page)
+    , m_selectors(move(selectors))
+    , m_style(style)
+{
+    m_style->set_parent_rule(*this);
+}
+
+void CSSPageRule::initialize(JS::Realm& realm)
+{
+    WEB_SET_PROTOTYPE_FOR_INTERFACE(CSSPageRule);
+    Base::initialize(realm);
+}
+
+// https://drafts.csswg.org/cssom/#dom-csspagerule-selectortext
+String CSSPageRule::selector_text() const
+{
+    // The selectorText attribute, on getting, must return the result of serializing the associated selector list.
+    return serialize_a_group_of_selectors(m_selectors);
+}
+
+// https://drafts.csswg.org/cssom/#dom-csspagerule-selectortext
+void CSSPageRule::set_selector_text(StringView)
+{
+    // FIXME: On setting the selectorText attribute these steps must be run:
+    //  1. Run the parse a list of CSS page selectors algorithm on the given value.
+    //  2. If the algorithm returns a non-null value replace the associated selector list with the returned value.
+    //  3. Otherwise, if the algorithm returns a null value, do nothing.
+}
+
+// https://drafts.csswg.org/cssom/#ref-for-csspagerule
+String CSSPageRule::serialized() const
+{
+    auto& descriptors = *m_style;
+
+    StringBuilder builder;
+
+    // AD-HOC: There's no spec for this yet.
+    builder.append("@page "sv);
+    if (auto selector = selector_text(); !selector.is_empty())
+        builder.appendff("{} ", selector);
+    builder.append("{ "sv);
+    if (descriptors.length() > 0) {
+        builder.append(descriptors.serialized());
+        builder.append(' ');
+    }
+    builder.append("}"sv);
+
+    return builder.to_string_without_validation();
+}
+
+void CSSPageRule::visit_edges(Visitor& visitor)
+{
+    Base::visit_edges(visitor);
+    visitor.visit(m_style);
+}
+
+}

Libraries/LibWeb/CSS/CSSPageRule.h

@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) 2025, Sam Atkins <sam@ladybird.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <LibWeb/CSS/CSSGroupingRule.h>
+#include <LibWeb/CSS/CSSPageDescriptors.h>
+#include <LibWeb/CSS/Selector.h>
+
+namespace Web::CSS {
+
+// https://drafts.csswg.org/css-page-3/#at-ruledef-page
+class CSSPageRule final : public CSSGroupingRule {
+    WEB_PLATFORM_OBJECT(CSSPageRule, CSSGroupingRule);
+    GC_DECLARE_ALLOCATOR(CSSPageRule);
+
+public:
+    [[nodiscard]] static GC::Ref<CSSPageRule> create(JS::Realm&, SelectorList&&, GC::Ref<CSSPageDescriptors>, CSSRuleList&);
+
+    virtual ~CSSPageRule() override = default;
+
+    String selector_text() const;
+    void set_selector_text(StringView);
+
+    GC::Ref<CSSPageDescriptors> style() { return m_style; }
+    GC::Ref<CSSPageDescriptors const> descriptors() const { return m_style; }
+
+private:
+    CSSPageRule(JS::Realm&, SelectorList&&, GC::Ref<CSSPageDescriptors>, CSSRuleList&);
+
+    virtual void initialize(JS::Realm&) override;
+    virtual String serialized() const override;
+    virtual void visit_edges(Visitor&) override;
+
+    SelectorList m_selectors;
+    GC::Ref<CSSPageDescriptors> m_style;
+};
+
+}

Libraries/LibWeb/CSS/CSSPageRule.idl

@@ -0,0 +1,9 @@
+#import <CSS/CSSGroupingRule.idl>
+#import <CSS/CSSPageDescriptors.idl>
+
+// https://drafts.csswg.org/cssom/#csspagerule
+[Exposed=Window]
+interface CSSPageRule : CSSGroupingRule {
+    attribute CSSOMString selectorText;
+    [SameObject, PutForwards=cssText] readonly attribute CSSPageDescriptors style;
+};

Libraries/LibWeb/CSS/CSSRule.cpp

@@ -94,6 +94,7 @@ FlyString const& CSSRule::parent_layer_internal_qualified_name_slow_case() const
         case Type::Supports:
         case Type::NestedDeclarations:
         case Type::Property:
+        case Type::Page:
             break;
         }
     }

Libraries/LibWeb/CSS/CSSRule.h

@@ -28,6 +28,7 @@ public:
         Import = 3,
         Media = 4,
         FontFace = 5,
+        Page = 6,
         Keyframes = 7,
         Keyframe = 8,
         Namespace = 10,

Libraries/LibWeb/CSS/CSSRuleList.cpp

@@ -164,6 +164,7 @@ void CSSRuleList::for_each_effective_rule(TraversalOrder order, Function<void(We
         case CSSRule::Type::Namespace:
         case CSSRule::Type::NestedDeclarations:
         case CSSRule::Type::Property:
+        case CSSRule::Type::Page:
             break;
         }
 
@@ -219,6 +220,7 @@ bool CSSRuleList::evaluate_media_queries(HTML::Window const& window)
         case CSSRule::Type::Namespace:
         case CSSRule::Type::NestedDeclarations:
         case CSSRule::Type::Property:
+        case CSSRule::Type::Page:
             break;
         }
     }

Libraries/LibWeb/CSS/Descriptors.json

@@ -104,6 +104,42 @@
       }
     }
   },
+  "page": {
+    "spec": "https://drafts.csswg.org/css-page-3/#at-page-rule",
+    "FIXME": "There are a lot more properties that are valid, see https://drafts.csswg.org/css-page-3/#properties-list",
+    "descriptors": {
+      "margin": {
+        "initial": "0",
+        "syntax": [
+          "<'margin'>"
+        ]
+      },
+      "margin-bottom": {
+        "initial": "0",
+        "syntax": [
+          "<'margin-bottom'>"
+        ]
+      },
+      "margin-left": {
+        "initial": "0",
+        "syntax": [
+          "<'margin-left'>"
+        ]
+      },
+      "margin-right": {
+        "initial": "0",
+        "syntax": [
+          "<'margin-right'>"
+        ]
+      },
+      "margin-top": {
+        "initial": "0",
+        "syntax": [
+          "<'margin-top'>"
+        ]
+      }
+    }
+  },
   "property": {
     "spec": "https://drafts.css-houdini.org/css-properties-values-api/#at-property-rule",
     "descriptors": {

Libraries/LibWeb/CSS/Parser/Parser.cpp

@@ -1375,6 +1375,8 @@ Vector<Descriptor> Parser::parse_as_descriptor_declaration_block(AtRuleID at_rul
         switch (at_rule_id) {
         case AtRuleID::FontFace:
             return RuleContext::AtFontFace;
+        case AtRuleID::Page:
+            return RuleContext::AtPage;
         case AtRuleID::Property:
             return RuleContext::AtProperty;
         }
@@ -1434,8 +1436,9 @@ bool Parser::is_valid_in_the_current_context(Declaration const&) const
         return m_rule_context.contains_slow(RuleContext::Style);
 
     case RuleContext::AtFontFace:
+    case RuleContext::AtPage:
     case RuleContext::AtProperty:
-        // @font-face and @property have descriptor declarations
+        // @font-face, @page, and @property have descriptor declarations
         return true;
 
     case RuleContext::AtKeyframes:
@@ -1482,8 +1485,10 @@ bool Parser::is_valid_in_the_current_context(AtRule const& at_rule) const
     case RuleContext::AtFontFace:
     case RuleContext::AtKeyframes:
     case RuleContext::Keyframe:
+    case RuleContext::AtPage:
     case RuleContext::AtProperty:
         // These can't contain any at-rules
+        // FIXME: Eventually @page can contain margin-box at-rules: https://drafts.csswg.org/css-page-3/#margin-at-rules
         return false;
     }
 
@@ -1522,6 +1527,7 @@ bool Parser::is_valid_in_the_current_context(QualifiedRule const&) const
         return false;
 
     case RuleContext::AtFontFace:
+    case RuleContext::AtPage:
     case RuleContext::AtProperty:
     case RuleContext::Keyframe:
         // These can't contain qualified rules

Libraries/LibWeb/CSS/Parser/Parser.h

@@ -245,8 +245,9 @@ private:
     GC::Ptr<CSSRule> convert_to_layer_rule(AtRule const&, Nested);
     GC::Ptr<CSSMediaRule> convert_to_media_rule(AtRule const&, Nested);
     GC::Ptr<CSSNamespaceRule> convert_to_namespace_rule(AtRule const&);
-    GC::Ptr<CSSSupportsRule> convert_to_supports_rule(AtRule const&, Nested);
+    GC::Ptr<CSSPageRule> convert_to_page_rule(AtRule const& rule);
     GC::Ptr<CSSPropertyRule> convert_to_property_rule(AtRule const& rule);
+    GC::Ptr<CSSSupportsRule> convert_to_supports_rule(AtRule const&, Nested);
 
     GC::Ref<CSSStyleProperties> convert_to_style_declaration(Vector<Declaration> const&);
     Optional<StyleProperty> convert_to_style_property(Declaration const&);

Libraries/LibWeb/CSS/Parser/RuleContext.cpp

@@ -27,6 +27,8 @@ RuleContext rule_context_type_for_rule(CSSRule::Type rule_type)
         return RuleContext::AtLayer;
     case CSSRule::Type::NestedDeclarations:
         return RuleContext::Style;
+    case CSSRule::Type::Page:
+        return RuleContext::AtPage;
     case CSSRule::Type::Property:
         return RuleContext::AtProperty;
         // Other types shouldn't be trying to create a context.
@@ -52,6 +54,8 @@ RuleContext rule_context_type_for_at_rule(FlyString const& name)
         return RuleContext::AtLayer;
     if (name == "property")
         return RuleContext::AtProperty;
+    if (name == "page")
+        return RuleContext::AtPage;
     return RuleContext::Unknown;
 }
 

Libraries/LibWeb/CSS/Parser/RuleContext.h

@@ -22,6 +22,7 @@ enum class RuleContext : u8 {
     SupportsCondition,
     AtLayer,
     AtProperty,
+    AtPage,
 };
 RuleContext rule_context_type_for_rule(CSSRule::Type);
 RuleContext rule_context_type_for_at_rule(FlyString const&);

Libraries/LibWeb/CSS/Parser/RuleParsing.cpp

@@ -21,6 +21,7 @@
 #include <LibWeb/CSS/CSSMediaRule.h>
 #include <LibWeb/CSS/CSSNamespaceRule.h>
 #include <LibWeb/CSS/CSSNestedDeclarations.h>
+#include <LibWeb/CSS/CSSPageRule.h>
 #include <LibWeb/CSS/CSSPropertyRule.h>
 #include <LibWeb/CSS/CSSStyleProperties.h>
 #include <LibWeb/CSS/CSSStyleRule.h>
@@ -64,12 +65,15 @@ GC::Ptr<CSSRule> Parser::convert_to_rule(Rule const& rule, Nested nested)
             if (at_rule.name.equals_ignoring_ascii_case("namespace"sv))
                 return convert_to_namespace_rule(at_rule);
 
-            if (at_rule.name.equals_ignoring_ascii_case("supports"sv))
-                return convert_to_supports_rule(at_rule, nested);
+            if (at_rule.name.equals_ignoring_ascii_case("page"sv))
+                return convert_to_page_rule(at_rule);
 
             if (at_rule.name.equals_ignoring_ascii_case("property"sv))
                 return convert_to_property_rule(at_rule);
 
+            if (at_rule.name.equals_ignoring_ascii_case("supports"sv))
+                return convert_to_supports_rule(at_rule, nested);
+
             // FIXME: More at rules!
             dbgln_if(CSS_PARSER_DEBUG, "Unrecognized CSS at-rule: @{}", at_rule.name);
             return {};
@@ -596,4 +600,43 @@ GC::Ptr<CSSFontFaceRule> Parser::convert_to_font_face_rule(AtRule const& rule)
     return CSSFontFaceRule::create(realm(), CSSFontFaceDescriptors::create(realm(), move(descriptors)));
 }
 
+GC::Ptr<CSSPageRule> Parser::convert_to_page_rule(AtRule const& rule)
+{
+    // https://drafts.csswg.org/css-page-3/#syntax-page-selector
+    // @page = @page <page-selector-list>? { <declaration-rule-list> }
+    // <page-selector-list> = <page-selector>#
+    // <page-selector> = [ <ident-token>? <pseudo-page>* ]!
+    // <pseudo-page> = : [ left | right | first | blank ]
+    SelectorList page_selectors;
+    // FIXME: Parse page selectors
+    if (rule.prelude.find_first_index_if([](ComponentValue const& it) { return !it.is(Token::Type::Whitespace); }).has_value()) {
+        dbgln("@page prelude wasn't empty!");
+        return nullptr;
+    }
+
+    GC::RootVector<GC::Ref<CSSRule>> child_rules { realm().heap() };
+    Vector<Descriptor> descriptors;
+    HashTable<DescriptorID> seen_descriptor_ids;
+    rule.for_each_as_declaration_rule_list(
+        [&](auto& at_rule) {
+            // FIXME: Parse margin rules here.
+            (void)at_rule;
+        },
+        [&](auto& declaration) {
+            if (auto descriptor = convert_to_descriptor(AtRuleID::Page, declaration); descriptor.has_value()) {
+                if (seen_descriptor_ids.contains(descriptor->descriptor_id)) {
+                    descriptors.remove_first_matching([&descriptor](Descriptor const& existing) {
+                        return existing.descriptor_id == descriptor->descriptor_id;
+                    });
+                } else {
+                    seen_descriptor_ids.set(descriptor->descriptor_id);
+                }
+                descriptors.append(descriptor.release_value());
+            }
+        });
+
+    auto rule_list = CSSRuleList::create(realm(), child_rules);
+    return CSSPageRule::create(realm(), move(page_selectors), CSSPageDescriptors::create(realm(), move(descriptors)), rule_list);
+}
+
 }

Libraries/LibWeb/CSS/StyleComputer.cpp

@@ -3027,8 +3027,9 @@ void StyleComputer::build_qualified_layer_names_cache()
             case CSSRule::Type::Keyframe:
             case CSSRule::Type::Namespace:
             case CSSRule::Type::NestedDeclarations:
-            case CSSRule::Type::Supports:
+            case CSSRule::Type::Page:
             case CSSRule::Type::Property:
+            case CSSRule::Type::Supports:
                 break;
             }
         });

Libraries/LibWeb/Dump.cpp

@@ -19,6 +19,7 @@
 #include <LibWeb/CSS/CSSMediaRule.h>
 #include <LibWeb/CSS/CSSNamespaceRule.h>
 #include <LibWeb/CSS/CSSNestedDeclarations.h>
+#include <LibWeb/CSS/CSSPageRule.h>
 #include <LibWeb/CSS/CSSPropertyRule.h>
 #include <LibWeb/CSS/CSSRule.h>
 #include <LibWeb/CSS/CSSStyleProperties.h>
@@ -695,15 +696,18 @@ void dump_rule(StringBuilder& builder, CSS::CSSRule const& rule, int indent_leve
     case CSS::CSSRule::Type::NestedDeclarations:
         dump_nested_declarations(builder, as<CSS::CSSNestedDeclarations const>(rule), indent_levels);
         break;
+    case CSS::CSSRule::Type::Page:
+        dump_page_rule(builder, as<CSS::CSSPageRule const>(rule), indent_levels);
+        break;
+    case CSS::CSSRule::Type::Property:
+        dump_property_rule(builder, as<CSS::CSSPropertyRule const>(rule), indent_levels);
+        break;
     case CSS::CSSRule::Type::Style:
         dump_style_rule(builder, as<CSS::CSSStyleRule const>(rule), indent_levels);
         break;
     case CSS::CSSRule::Type::Supports:
         dump_supports_rule(builder, as<CSS::CSSSupportsRule const>(rule), indent_levels);
         break;
-    case CSS::CSSRule::Type::Property:
-        dump_property_rule(builder, as<CSS::CSSPropertyRule const>(rule), indent_levels);
-        break;
     }
 }
 
@@ -765,6 +769,13 @@ void dump_media_rule(StringBuilder& builder, CSS::CSSMediaRule const& media, int
         dump_rule(builder, rule, indent_levels + 2);
 }
 
+void dump_page_rule(StringBuilder& builder, CSS::CSSPageRule const& page, int indent_levels)
+{
+    indent(builder, indent_levels + 1);
+    builder.appendff("selector: {}\n", page.selector_text());
+    dump_descriptors(builder, page.descriptors(), indent_levels + 1);
+}
+
 void dump_supports_rule(StringBuilder& builder, CSS::CSSSupportsRule const& supports, int indent_levels)
 {
     indent(builder, indent_levels);

Libraries/LibWeb/Dump.h

@@ -30,6 +30,7 @@ void dump_import_rule(StringBuilder&, CSS::CSSImportRule const&, int indent_leve
 void dump_keyframe_rule(StringBuilder&, CSS::CSSKeyframeRule const&, int indent_levels = 0);
 void dump_keyframes_rule(StringBuilder&, CSS::CSSKeyframesRule const&, int indent_levels = 0);
 void dump_media_rule(StringBuilder&, CSS::CSSMediaRule const&, int indent_levels = 0);
+void dump_page_rule(StringBuilder&, CSS::CSSPageRule const&, int indent_levels = 0);
 void dump_style_rule(StringBuilder&, CSS::CSSStyleRule const&, int indent_levels = 0);
 void dump_supports_rule(StringBuilder&, CSS::CSSSupportsRule const&, int indent_levels = 0);
 void dump_property_rule(StringBuilder&, CSS::CSSPropertyRule const&, int indent_levels = 0);

Libraries/LibWeb/Forward.h

@@ -205,6 +205,8 @@ class CSSNamespaceRule;
 class CSSNestedDeclarations;
 class CSSOKLab;
 class CSSOKLCH;
+class CSSPageRule;
+class CSSPageDescriptors;
 class CSSPropertyRule;
 class CSSRGB;
 class CSSRule;

Libraries/LibWeb/idl_files.cmake

@@ -35,6 +35,8 @@ libweb_js_bindings(CSS/CSSMediaRule)
 libweb_js_bindings(CSS/CSS NAMESPACE)
 libweb_js_bindings(CSS/CSSNamespaceRule)
 libweb_js_bindings(CSS/CSSNestedDeclarations)
+libweb_js_bindings(CSS/CSSPageRule)
+libweb_js_bindings(CSS/CSSPageDescriptors)
 libweb_js_bindings(CSS/CSSPropertyRule)
 libweb_js_bindings(CSS/CSSRule)
 libweb_js_bindings(CSS/CSSRuleList)

Tests/LibWeb/Text/expected/all-window-properties.txt

@@ -49,6 +49,8 @@ CSSLayerStatementRule
 CSSMediaRule
 CSSNamespaceRule
 CSSNestedDeclarations
+CSSPageDescriptors
+CSSPageRule
 CSSPropertyRule
 CSSRule
 CSSRuleList

Tests/LibWeb/Text/expected/wpt-import/css/css-page/cssom/page-001.txt

@@ -2,8 +2,9 @@ Harness status: OK
 
 Found 4 tests
 
-4 Fail
+1 Pass
+3 Fail
 Fail	There should be 3 @page rules.
-Fail	Rule #0
+Pass	Rule #0
 Fail	Rule #1
 Fail	Rule #2

Tests/LibWeb/Text/expected/wpt-import/css/css-page/cssom/page-002.txt

@@ -1,3 +1,7 @@
-Harness status: Error
+Harness status: OK
 
-Found 0 tests
+Found 2 tests
+
+2 Fail
+Fail	Add declarations
+Fail	Remove declarations

Tests/LibWeb/Text/expected/wpt-import/css/css-page/parsing/page-rules-001.txt

@@ -2,11 +2,11 @@ Harness status: OK
 
 Found 8 tests
 
-4 Pass
-4 Fail
+5 Pass
+3 Fail
 Pass	page-rules-001
 Pass	@page , { } should be an invalid rule
-Fail	@page { } should be a valid rule
+Pass	@page { } should be a valid rule
 Fail	@page a { } should be a valid rule
 Fail	@page page1 { } should be a valid rule
 Fail	@page name1, name2 { } should be a valid rule

Tests/LibWeb/Text/expected/wpt-import/css/css-page/parsing/size-valid.txt

@@ -2,8 +2,9 @@ Harness status: OK
 
 Found 15 tests
 
-15 Fail
-Fail	Test setup
+1 Pass
+14 Fail
+Pass	Test setup
 Fail	size: 640px 480px
 Fail	size: 8.5in 11in
 Fail	size: 3in 10in

Tests/LibWeb/Text/expected/wpt-import/css/cssom/cssimportrule.txt

@@ -2,8 +2,8 @@ Harness status: OK
 
 Found 11 tests
 
-8 Pass
-3 Fail
+9 Pass
+2 Fail
 Pass	CSSRule and CSSImportRule types
 Pass	Type of CSSRule#type and constant values
 Pass	Existence and writability of CSSRule attributes
@@ -11,7 +11,7 @@ Pass	Values of CSSRule attributes
 Pass	Existence and writability of CSSImportRule attributes
 Fail	Values of CSSImportRule attributes
 Fail	CSSImportRule : MediaList mediaText attribute should be updated due to [PutForwards]
-Fail	CSSStyleDeclaration cssText attribute should be updated due to [PutForwards]
+Pass	CSSStyleDeclaration cssText attribute should be updated due to [PutForwards]
 Pass	StyleSheet : MediaList mediaText attribute should be updated due to [PutForwards]
 Pass	Existence and writability of CSSImportRule supportsText attribute
 Pass	Value of CSSImportRule supportsText attribute