diff --git a/Libraries/LibWeb/CSS/Properties.json b/Libraries/LibWeb/CSS/Properties.json
index a171d0e297c..d09124119af 100644
--- a/Libraries/LibWeb/CSS/Properties.json
+++ b/Libraries/LibWeb/CSS/Properties.json
@@ -1868,10 +1868,20 @@
     "percentages-resolve-to": "length"
   },
   "inset-block": {
-    "logical-alias-for": [
-      "inset"
+    "initial": "auto",
+    "longhands": [
+      "inset-block-start",
+      "inset-block-end"
     ],
-    "max-values": 2
+    "max-values": 2,
+    "valid-types": [
+      "length [-∞,∞]",
+      "percentage [-∞,∞]"
+    ],
+    "valid-identifiers": [
+      "auto"
+    ],
+    "percentages-resolve-to": "length"
   },
   "inset-block-end": {
     "logical-alias-for": [
@@ -1892,10 +1902,20 @@
     "max-values": 1
   },
   "inset-inline": {
-    "logical-alias-for": [
-      "inset"
+    "initial": "auto",
+    "longhands": [
+      "inset-inline-start",
+      "inset-inline-end"
     ],
-    "max-values": 2
+    "max-values": 2,
+    "valid-types": [
+      "length [-∞,∞]",
+      "percentage [-∞,∞]"
+    ],
+    "valid-identifiers": [
+      "auto"
+    ],
+    "percentages-resolve-to": "length"
   },
   "inset-inline-end": {
     "logical-alias-for": [
@@ -2053,10 +2073,20 @@
     ]
   },
   "margin-block": {
-    "logical-alias-for": [
-      "margin"
+    "initial": "0",
+    "longhands": [
+      "margin-block-start",
+      "margin-block-end"
     ],
-    "max-values": 2
+    "max-values": 2,
+    "valid-types": [
+      "length [-∞,∞]",
+      "percentage [-∞,∞]"
+    ],
+    "valid-identifiers": [
+      "auto"
+    ],
+    "percentages-resolve-to": "length"
   },
   "margin-block-end": {
     "logical-alias-for": [
@@ -2091,10 +2121,20 @@
     ]
   },
   "margin-inline": {
-    "logical-alias-for": [
-      "margin"
+    "initial": "0",
+    "longhands": [
+      "margin-inline-start",
+      "margin-inline-end"
     ],
-    "max-values": 2
+    "max-values": 2,
+    "valid-types": [
+      "length [-∞,∞]",
+      "percentage [-∞,∞]"
+    ],
+    "valid-identifiers": [
+      "auto"
+    ],
+    "percentages-resolve-to": "length"
   },
   "margin-inline-end": {
     "logical-alias-for": [
@@ -2469,10 +2509,17 @@
     ]
   },
   "padding-block": {
-    "logical-alias-for": [
-      "padding"
+    "initial": "0",
+    "longhands": [
+      "padding-block-start",
+      "padding-block-end"
     ],
-    "max-values": 2
+    "max-values": 2,
+    "valid-types": [
+      "length [0,∞]",
+      "percentage [0,∞]"
+    ],
+    "percentages-resolve-to": "length"
   },
   "padding-block-end": {
     "logical-alias-for": [
@@ -2504,10 +2551,17 @@
     ]
   },
   "padding-inline": {
-    "logical-alias-for": [
-      "padding"
+    "initial": "0",
+    "longhands": [
+      "padding-inline-start",
+      "padding-inline-end"
     ],
-    "max-values": 2
+    "max-values": 2,
+    "valid-types": [
+      "length [0,∞]",
+      "percentage [0,∞]"
+    ],
+    "percentages-resolve-to": "length"
   },
   "padding-inline-end": {
     "logical-alias-for": [
diff --git a/Libraries/LibWeb/CSS/StyleComputer.cpp b/Libraries/LibWeb/CSS/StyleComputer.cpp
index 99dd319e0e2..231f938b58c 100644
--- a/Libraries/LibWeb/CSS/StyleComputer.cpp
+++ b/Libraries/LibWeb/CSS/StyleComputer.cpp
@@ -687,48 +687,11 @@ void StyleComputer::for_each_property_expanding_shorthands(PropertyID property_i
         }
     };
 
-    struct StartAndEndPropertyIDs {
-        PropertyID start;
-        PropertyID end;
-    };
-    auto map_logical_property_to_real_properties = [](PropertyID property_id) -> Optional<StartAndEndPropertyIDs> {
-        // FIXME: Honor writing-mode, direction and text-orientation.
-        switch (property_id) {
-        case PropertyID::MarginBlock:
-            return StartAndEndPropertyIDs { PropertyID::MarginTop, PropertyID::MarginBottom };
-        case PropertyID::MarginInline:
-            return StartAndEndPropertyIDs { PropertyID::MarginLeft, PropertyID::MarginRight };
-        case PropertyID::PaddingBlock:
-            return StartAndEndPropertyIDs { PropertyID::PaddingTop, PropertyID::PaddingBottom };
-        case PropertyID::PaddingInline:
-            return StartAndEndPropertyIDs { PropertyID::PaddingLeft, PropertyID::PaddingRight };
-        case PropertyID::InsetBlock:
-            return StartAndEndPropertyIDs { PropertyID::Top, PropertyID::Bottom };
-        case PropertyID::InsetInline:
-            return StartAndEndPropertyIDs { PropertyID::Left, PropertyID::Right };
-        default:
-            return {};
-        }
-    };
-
     if (auto real_property_id = map_logical_property_to_real_property(property_id); real_property_id.has_value()) {
         for_each_property_expanding_shorthands(real_property_id.value(), value, set_longhand_property);
         return;
     }
 
-    if (auto real_property_ids = map_logical_property_to_real_properties(property_id); real_property_ids.has_value()) {
-        if (value.is_value_list() && value.as_value_list().size() == 2) {
-            auto const& start = value.as_value_list().values()[0];
-            auto const& end = value.as_value_list().values()[1];
-            for_each_property_expanding_shorthands(real_property_ids->start, start, set_longhand_property);
-            for_each_property_expanding_shorthands(real_property_ids->end, end, set_longhand_property);
-            return;
-        }
-        for_each_property_expanding_shorthands(real_property_ids->start, value, set_longhand_property);
-        for_each_property_expanding_shorthands(real_property_ids->end, value, set_longhand_property);
-        return;
-    }
-
     if (value.is_shorthand()) {
         auto& shorthand_value = value.as_shorthand();
         auto& properties = shorthand_value.sub_properties();
@@ -762,6 +725,16 @@ void StyleComputer::for_each_property_expanding_shorthands(PropertyID property_i
         }
     };
 
+    auto assign_start_and_end_values = [&](PropertyID start_property, PropertyID end_property, auto const& values) {
+        if (values.is_value_list()) {
+            set_longhand_property(start_property, value.as_value_list().values()[0]);
+            set_longhand_property(end_property, value.as_value_list().values()[1]);
+        } else {
+            set_longhand_property(start_property, value);
+            set_longhand_property(end_property, value);
+        }
+    };
+
     if (property_id == CSS::PropertyID::Border) {
         for_each_property_expanding_shorthands(CSS::PropertyID::BorderTop, value, set_longhand_property);
         for_each_property_expanding_shorthands(CSS::PropertyID::BorderRight, value, set_longhand_property);
@@ -859,6 +832,16 @@ void StyleComputer::for_each_property_expanding_shorthands(PropertyID property_i
         return;
     }
 
+    if (property_id == CSS::PropertyID::InsetBlock) {
+        assign_start_and_end_values(PropertyID::InsetBlockStart, PropertyID::InsetBlockEnd, value);
+        return;
+    }
+
+    if (property_id == CSS::PropertyID::InsetInline) {
+        assign_start_and_end_values(PropertyID::InsetInlineStart, PropertyID::InsetInlineEnd, value);
+        return;
+    }
+
     if (property_id == CSS::PropertyID::Margin) {
         if (value.is_value_list()) {
             auto const& values_list = value.as_value_list();
@@ -873,6 +856,16 @@ void StyleComputer::for_each_property_expanding_shorthands(PropertyID property_i
         return;
     }
 
+    if (property_id == CSS::PropertyID::MarginBlock) {
+        assign_start_and_end_values(PropertyID::MarginBlockStart, PropertyID::MarginBlockEnd, value);
+        return;
+    }
+
+    if (property_id == CSS::PropertyID::MarginInline) {
+        assign_start_and_end_values(PropertyID::MarginInlineStart, PropertyID::MarginInlineEnd, value);
+        return;
+    }
+
     if (property_id == CSS::PropertyID::Padding) {
         if (value.is_value_list()) {
             auto const& values_list = value.as_value_list();
@@ -887,6 +880,16 @@ void StyleComputer::for_each_property_expanding_shorthands(PropertyID property_i
         return;
     }
 
+    if (property_id == CSS::PropertyID::PaddingBlock) {
+        assign_start_and_end_values(PropertyID::PaddingBlockStart, PropertyID::PaddingBlockEnd, value);
+        return;
+    }
+
+    if (property_id == CSS::PropertyID::PaddingInline) {
+        assign_start_and_end_values(PropertyID::PaddingInlineStart, PropertyID::PaddingInlineEnd, value);
+        return;
+    }
+
     if (property_id == CSS::PropertyID::Gap) {
         if (value.is_value_list()) {
             auto const& values_list = value.as_value_list();