diff --git a/Cargo.lock b/Cargo.lock
index 1503ed81b1a9..59df99f7bce6 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1206,7 +1206,7 @@ dependencies = [
 [[package]]
 name = "derive_common"
 version = "0.0.1"
-source = "git+https://github.com/servo/stylo?branch=2024-04-16#81a55acca3f274fce0e365d567c4e7c4cb350d22"
+source = "git+https://github.com/servo/stylo?rev=6faedad67ac2e320b51ac72a165b0ceb52caf918#6faedad67ac2e320b51ac72a165b0ceb52caf918"
 dependencies = [
  "darling",
  "proc-macro2",
@@ -3550,7 +3550,7 @@ dependencies = [
 [[package]]
 name = "malloc_size_of"
 version = "0.0.1"
-source = "git+https://github.com/servo/stylo?branch=2024-04-16#81a55acca3f274fce0e365d567c4e7c4cb350d22"
+source = "git+https://github.com/servo/stylo?rev=6faedad67ac2e320b51ac72a165b0ceb52caf918#6faedad67ac2e320b51ac72a165b0ceb52caf918"
 dependencies = [
  "accountable-refcell",
  "app_units",
@@ -5168,7 +5168,7 @@ dependencies = [
 [[package]]
 name = "selectors"
 version = "0.24.0"
-source = "git+https://github.com/servo/stylo?branch=2024-04-16#81a55acca3f274fce0e365d567c4e7c4cb350d22"
+source = "git+https://github.com/servo/stylo?rev=6faedad67ac2e320b51ac72a165b0ceb52caf918#6faedad67ac2e320b51ac72a165b0ceb52caf918"
 dependencies = [
  "bitflags 2.5.0",
  "cssparser",
@@ -5456,7 +5456,7 @@ dependencies = [
 [[package]]
 name = "servo_arc"
 version = "0.2.0"
-source = "git+https://github.com/servo/stylo?branch=2024-04-16#81a55acca3f274fce0e365d567c4e7c4cb350d22"
+source = "git+https://github.com/servo/stylo?rev=6faedad67ac2e320b51ac72a165b0ceb52caf918#6faedad67ac2e320b51ac72a165b0ceb52caf918"
 dependencies = [
  "nodrop",
  "serde",
@@ -5466,7 +5466,7 @@ dependencies = [
 [[package]]
 name = "servo_atoms"
 version = "0.0.1"
-source = "git+https://github.com/servo/stylo?branch=2024-04-16#81a55acca3f274fce0e365d567c4e7c4cb350d22"
+source = "git+https://github.com/servo/stylo?rev=6faedad67ac2e320b51ac72a165b0ceb52caf918#6faedad67ac2e320b51ac72a165b0ceb52caf918"
 dependencies = [
  "string_cache",
  "string_cache_codegen",
@@ -5664,7 +5664,7 @@ checksum = "38b58827f4464d87d377d175e90bf58eb00fd8716ff0a62f80356b5e61555d0d"
 [[package]]
 name = "size_of_test"
 version = "0.0.1"
-source = "git+https://github.com/servo/stylo?branch=2024-04-16#81a55acca3f274fce0e365d567c4e7c4cb350d22"
+source = "git+https://github.com/servo/stylo?rev=6faedad67ac2e320b51ac72a165b0ceb52caf918#6faedad67ac2e320b51ac72a165b0ceb52caf918"
 dependencies = [
  "static_assertions",
 ]
@@ -5789,7 +5789,7 @@ checksum = "a2eb9349b6444b326872e140eb1cf5e7c522154d69e7a0ffb0fb81c06b37543f"
 [[package]]
 name = "static_prefs"
 version = "0.1.0"
-source = "git+https://github.com/servo/stylo?branch=2024-04-16#81a55acca3f274fce0e365d567c4e7c4cb350d22"
+source = "git+https://github.com/servo/stylo?rev=6faedad67ac2e320b51ac72a165b0ceb52caf918#6faedad67ac2e320b51ac72a165b0ceb52caf918"
 
 [[package]]
 name = "strict-num"
@@ -5826,7 +5826,7 @@ dependencies = [
 [[package]]
 name = "style"
 version = "0.0.1"
-source = "git+https://github.com/servo/stylo?branch=2024-04-16#81a55acca3f274fce0e365d567c4e7c4cb350d22"
+source = "git+https://github.com/servo/stylo?rev=6faedad67ac2e320b51ac72a165b0ceb52caf918#6faedad67ac2e320b51ac72a165b0ceb52caf918"
 dependencies = [
  "app_units",
  "arrayvec",
@@ -5885,7 +5885,7 @@ dependencies = [
 [[package]]
 name = "style_config"
 version = "0.0.1"
-source = "git+https://github.com/servo/stylo?branch=2024-04-16#81a55acca3f274fce0e365d567c4e7c4cb350d22"
+source = "git+https://github.com/servo/stylo?rev=6faedad67ac2e320b51ac72a165b0ceb52caf918#6faedad67ac2e320b51ac72a165b0ceb52caf918"
 dependencies = [
  "lazy_static",
 ]
@@ -5893,7 +5893,7 @@ dependencies = [
 [[package]]
 name = "style_derive"
 version = "0.0.1"
-source = "git+https://github.com/servo/stylo?branch=2024-04-16#81a55acca3f274fce0e365d567c4e7c4cb350d22"
+source = "git+https://github.com/servo/stylo?rev=6faedad67ac2e320b51ac72a165b0ceb52caf918#6faedad67ac2e320b51ac72a165b0ceb52caf918"
 dependencies = [
  "darling",
  "derive_common",
@@ -5924,7 +5924,7 @@ dependencies = [
 [[package]]
 name = "style_traits"
 version = "0.0.1"
-source = "git+https://github.com/servo/stylo?branch=2024-04-16#81a55acca3f274fce0e365d567c4e7c4cb350d22"
+source = "git+https://github.com/servo/stylo?rev=6faedad67ac2e320b51ac72a165b0ceb52caf918#6faedad67ac2e320b51ac72a165b0ceb52caf918"
 dependencies = [
  "app_units",
  "bitflags 2.5.0",
@@ -6287,7 +6287,7 @@ checksum = "1f3ccbac311fea05f86f61904b462b55fb3df8837a366dfc601a0161d0532f20"
 [[package]]
 name = "to_shmem"
 version = "0.0.1"
-source = "git+https://github.com/servo/stylo?branch=2024-04-16#81a55acca3f274fce0e365d567c4e7c4cb350d22"
+source = "git+https://github.com/servo/stylo?rev=6faedad67ac2e320b51ac72a165b0ceb52caf918#6faedad67ac2e320b51ac72a165b0ceb52caf918"
 dependencies = [
  "cssparser",
  "servo_arc",
@@ -6300,7 +6300,7 @@ dependencies = [
 [[package]]
 name = "to_shmem_derive"
 version = "0.0.1"
-source = "git+https://github.com/servo/stylo?branch=2024-04-16#81a55acca3f274fce0e365d567c4e7c4cb350d22"
+source = "git+https://github.com/servo/stylo?rev=6faedad67ac2e320b51ac72a165b0ceb52caf918#6faedad67ac2e320b51ac72a165b0ceb52caf918"
 dependencies = [
  "darling",
  "derive_common",
diff --git a/Cargo.toml b/Cargo.toml
index f4e35a476378..db5f20fd35b6 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -64,7 +64,7 @@ keyboard-types = "0.6"
 lazy_static = "1.4"
 libc = "0.2"
 log = "0.4"
-malloc_size_of = { git = "https://github.com/servo/stylo", branch = "2024-04-16", features = ["servo"] }
+malloc_size_of = { git = "https://github.com/servo/stylo", rev = "6faedad67ac2e320b51ac72a165b0ceb52caf918", features = ["servo"] }
 malloc_size_of_derive = "0.1"
 mime = "0.3.13"
 mime_guess = "2.0.3"
@@ -87,31 +87,31 @@ rustls = { version = "0.21.12", features = ["dangerous_configuration"] }
 rustls-pemfile = "1.0.4"
 script_layout_interface = { path = "components/shared/script_layout" }
 script_traits = { path = "components/shared/script" }
-selectors = { git = "https://github.com/servo/stylo", branch = "2024-04-16" }
+selectors = { git = "https://github.com/servo/stylo", rev = "6faedad67ac2e320b51ac72a165b0ceb52caf918" }
 serde = "1.0.198"
 serde_bytes = "0.11"
 serde_json = "1.0"
 servo-media = { git = "https://github.com/servo/media" }
 servo-media-dummy = { git = "https://github.com/servo/media" }
 servo-media-gstreamer = { git = "https://github.com/servo/media" }
-servo_arc = { git = "https://github.com/servo/stylo", branch = "2024-04-16" }
-servo_atoms = { git = "https://github.com/servo/stylo", branch = "2024-04-16" }
-size_of_test = { git = "https://github.com/servo/stylo", branch = "2024-04-16" }
+servo_arc = { git = "https://github.com/servo/stylo", rev = "6faedad67ac2e320b51ac72a165b0ceb52caf918" }
+servo_atoms = { git = "https://github.com/servo/stylo", rev = "6faedad67ac2e320b51ac72a165b0ceb52caf918" }
+size_of_test = { git = "https://github.com/servo/stylo", rev = "6faedad67ac2e320b51ac72a165b0ceb52caf918" }
 smallbitvec = "2.5.3"
 smallvec = "1.13"
 sparkle = "0.1.26"
 string_cache = "0.8"
 string_cache_codegen = "0.5"
-style = { git = "https://github.com/servo/stylo", branch = "2024-04-16", features = ["servo"] }
-style_config = { git = "https://github.com/servo/stylo", branch = "2024-04-16" }
-style_traits = { git = "https://github.com/servo/stylo", branch = "2024-04-16", features = ["servo"] }
+style = { git = "https://github.com/servo/stylo", rev = "6faedad67ac2e320b51ac72a165b0ceb52caf918", features = ["servo"] }
+style_config = { git = "https://github.com/servo/stylo", rev = "6faedad67ac2e320b51ac72a165b0ceb52caf918" }
+style_traits = { git = "https://github.com/servo/stylo", rev = "6faedad67ac2e320b51ac72a165b0ceb52caf918", features = ["servo"] }
 # NOTE: the sm-angle feature only 2024-03-01rms!
 surfman = { version = "0.9", features = ["chains", "sm-angle", "sm-angle-default"] }
 syn = { version = "2", default-features = false, features = ["clone-impls", "derive", "parsing"] }
 synstructure = "0.13"
 thin-vec = "0.2.13"
 time = "0.1.41"
-to_shmem = { git = "https://github.com/servo/stylo", branch = "2024-04-16" }
+to_shmem = { git = "https://github.com/servo/stylo", rev = "6faedad67ac2e320b51ac72a165b0ceb52caf918" }
 tokio = "1"
 tokio-rustls = "0.24"
 tungstenite = "0.20"
diff --git a/components/layout_2020/flexbox/layout.rs b/components/layout_2020/flexbox/layout.rs
index 71488d833814..393ce99760bb 100644
--- a/components/layout_2020/flexbox/layout.rs
+++ b/components/layout_2020/flexbox/layout.rs
@@ -48,6 +48,8 @@ struct FlexContext<'a> {
     container_min_cross_size: Length,
     container_max_cross_size: Option<Length>,
     flex_axis: FlexAxis,
+    flex_direction_is_reversed: bool,
+    flex_wrap_reverse: bool,
     main_start_cross_start_sides_are: MainStartCrossStart,
     container_definite_inner_size: FlexRelativeVec2<Option<Length>>,
     align_content: AlignContent,
@@ -218,6 +220,10 @@ impl FlexContainer {
             FlexWrap::Wrap | FlexWrap::WrapReverse => false,
         };
         let flex_axis = FlexAxis::from(flex_direction);
+        let flex_direction_is_reversed = match flex_direction {
+            FlexDirection::Row | FlexDirection::Column => false,
+            FlexDirection::RowReverse | FlexDirection::ColumnReverse => true,
+        };
         let flex_wrap_reverse = match flex_wrap {
             FlexWrap::Nowrap | FlexWrap::Wrap => false,
             FlexWrap::WrapReverse => true,
@@ -234,6 +240,8 @@ impl FlexContainer {
             container_max_cross_size,
             container_is_single_line,
             flex_axis,
+            flex_direction_is_reversed,
+            flex_wrap_reverse,
             align_content,
             align_items,
             justify_content,
@@ -297,25 +305,80 @@ impl FlexContainer {
         // Align all flex lines per `align-content`.
         let line_count = flex_lines.len();
         let mut cross_start_position_cursor = Length::zero();
-
-        let line_interval = match flex_context.container_definite_inner_size.cross {
-            Some(cross_size) if line_count >= 2 => {
-                let free_space = cross_size - content_cross_size;
-
-                cross_start_position_cursor = match flex_context.align_content {
-                    AlignContent::Center => free_space / 2.0,
-                    AlignContent::SpaceAround => free_space / (line_count * 2) as CSSFloat,
-                    AlignContent::FlexEnd => free_space,
-                    _ => Length::zero(),
+        let mut line_interval = Length::zero();
+
+        if let Some(cross_size) = flex_context.container_definite_inner_size.cross {
+            let free_space = cross_size - content_cross_size;
+            let layout_is_flex_reversed = flex_context.flex_wrap_reverse;
+
+            // Implement fallback alignment.
+            //
+            // In addition to the spec at https://www.w3.org/TR/css-align-3/ this implementation follows
+            // the resolution of https://github.com/w3c/csswg-drafts/issues/10154
+            let resolved_align_content: AlignContent = {
+                // Inital values from the style system
+                let mut resolved_align_content = flex_context.align_content;
+                let mut is_safe = false; // FIXME: retrieve from style system
+
+                // Fallback occurs in two cases:
+
+                // 1. If there is only a single item being aligned and alignment is a distributed alignment keyword
+                //    https://www.w3.org/TR/css-align-3/#distribution-values
+                if line_count <= 1 || free_space <= Length::zero() {
+                    (resolved_align_content, is_safe) = match resolved_align_content {
+                        AlignContent::Stretch => (AlignContent::FlexStart, true),
+                        AlignContent::SpaceBetween => (AlignContent::FlexStart, true),
+                        AlignContent::SpaceAround => (AlignContent::Center, true),
+                        AlignContent::SpaceEvenly => (AlignContent::Center, true),
+                        _ => (resolved_align_content, is_safe),
+                    }
                 };
 
-                match flex_context.align_content {
-                    AlignContent::SpaceBetween => free_space / (line_count - 1) as CSSFloat,
-                    AlignContent::SpaceAround => free_space / line_count as CSSFloat,
-                    _ => Length::zero(),
+                // 2. If free space is negative the "safe" alignment variants all fallback to Start alignment
+                if free_space <= Length::zero() && is_safe {
+                    resolved_align_content = AlignContent::Start;
                 }
-            },
-            _ => Length::zero(),
+
+                resolved_align_content
+            };
+
+            // Implement "unsafe" alignment. "safe" alignment is handled by the fallback process above.
+            cross_start_position_cursor = match resolved_align_content {
+                AlignContent::Start => Length::zero(),
+                AlignContent::FlexStart => {
+                    if layout_is_flex_reversed {
+                        free_space
+                    } else {
+                        Length::zero()
+                    }
+                },
+                AlignContent::End => free_space,
+                AlignContent::FlexEnd => {
+                    if layout_is_flex_reversed {
+                        Length::zero()
+                    } else {
+                        free_space
+                    }
+                },
+                AlignContent::Center => free_space / 2.0,
+                AlignContent::Stretch => Length::zero(),
+                AlignContent::SpaceBetween => Length::zero(),
+                AlignContent::SpaceAround => (free_space / line_count as CSSFloat) / 2.0,
+                AlignContent::SpaceEvenly => free_space / (line_count + 1) as CSSFloat,
+            };
+
+            // TODO: Implement gap property
+            line_interval = /*gap + */ match resolved_align_content {
+                AlignContent::Start => Length::zero(),
+                AlignContent::FlexStart => Length::zero(),
+                AlignContent::End => Length::zero(),
+                AlignContent::FlexEnd => Length::zero(),
+                AlignContent::Center => Length::zero(),
+                AlignContent::Stretch => Length::zero(),
+                AlignContent::SpaceBetween => free_space / (line_count - 1) as CSSFloat,
+                AlignContent::SpaceAround => free_space / line_count as CSSFloat,
+                AlignContent::SpaceEvenly => free_space / (line_count + 1) as CSSFloat,
+            };
         };
 
         let line_cross_start_positions = flex_lines
@@ -698,7 +761,7 @@ impl FlexLine<'_> {
         flex_context: &mut FlexContext,
         container_main_size: Length,
     ) -> FlexLineLayoutResult {
-        let (item_used_main_sizes, remaining_free_space) =
+        let (item_used_main_sizes, mut free_space) =
             self.resolve_flexible_lengths(container_main_size);
 
         // https://drafts.csswg.org/css-flexbox/#algo-cross-item
@@ -757,35 +820,82 @@ impl FlexLine<'_> {
         // Distribute any remaining free space
         // https://drafts.csswg.org/css-flexbox/#algo-main-align
         let (item_main_margins, free_space_distributed) =
-            self.resolve_auto_main_margins(remaining_free_space);
+            self.resolve_auto_main_margins(free_space);
+        if free_space_distributed {
+            free_space = Length::zero();
+        }
 
         // Align the items along the main-axis per justify-content.
         let item_count = self.items.len();
-        let main_start_position = if free_space_distributed {
-            Length::zero()
-        } else {
-            match flex_context.justify_content {
-                JustifyContent::FlexEnd => remaining_free_space,
-                JustifyContent::Center => remaining_free_space / 2.0,
-                JustifyContent::SpaceAround => remaining_free_space / (item_count * 2) as CSSFloat,
-                _ => Length::zero(),
+        let layout_is_flex_reversed = flex_context.flex_direction_is_reversed;
+
+        // Implement fallback alignment.
+        //
+        // In addition to the spec at https://www.w3.org/TR/css-align-3/ this implementation follows
+        // the resolution of https://github.com/w3c/csswg-drafts/issues/10154
+        let resolved_justify_content: JustifyContent = {
+            // Inital values from the style system
+            let mut resolved_justify_content = flex_context.justify_content;
+            let mut is_safe = false; // FIXME: retrieve from style system
+
+            // Fallback occurs in two cases:
+
+            // 1. If there is only a single item being aligned and alignment is a distributed alignment keyword
+            //    https://www.w3.org/TR/css-align-3/#distribution-values
+            if item_count <= 1 || free_space <= Length::zero() {
+                (resolved_justify_content, is_safe) = match resolved_justify_content {
+                    JustifyContent::Stretch => (JustifyContent::FlexStart, true),
+                    JustifyContent::SpaceBetween => (JustifyContent::FlexStart, true),
+                    JustifyContent::SpaceAround => (JustifyContent::Center, true),
+                    JustifyContent::SpaceEvenly => (JustifyContent::Center, true),
+                    _ => (resolved_justify_content, is_safe),
+                }
+            };
+
+            // 2. If free space is negative the "safe" alignment variants all fallback to Start alignment
+            if free_space <= Length::zero() && is_safe {
+                resolved_justify_content = JustifyContent::Start;
             }
+
+            resolved_justify_content
         };
 
-        let item_main_interval = if free_space_distributed {
-            Length::zero()
-        } else {
-            match flex_context.justify_content {
-                JustifyContent::SpaceBetween => {
-                    if item_count > 1 {
-                        remaining_free_space / (item_count - 1) as CSSFloat
-                    } else {
-                        Length::zero()
-                    }
-                },
-                JustifyContent::SpaceAround => remaining_free_space / item_count as CSSFloat,
-                _ => Length::zero(),
-            }
+        // Implement "unsafe" alignment. "safe" alignment is handled by the fallback process above.
+        let main_start_position = match resolved_justify_content {
+            JustifyContent::Start => Length::zero(),
+            JustifyContent::FlexStart => {
+                if layout_is_flex_reversed {
+                    free_space
+                } else {
+                    Length::zero()
+                }
+            },
+            JustifyContent::End => free_space,
+            JustifyContent::FlexEnd => {
+                if layout_is_flex_reversed {
+                    Length::zero()
+                } else {
+                    free_space
+                }
+            },
+            JustifyContent::Center => free_space / 2.0,
+            JustifyContent::Stretch => Length::zero(),
+            JustifyContent::SpaceBetween => Length::zero(),
+            JustifyContent::SpaceAround => (free_space / item_count as CSSFloat) / 2.0,
+            JustifyContent::SpaceEvenly => free_space / (item_count + 1) as CSSFloat,
+        };
+
+        // TODO: Implement gap property
+        let item_main_interval = /*gap + */ match resolved_justify_content {
+            JustifyContent::Start => Length::zero(),
+            JustifyContent::FlexStart => Length::zero(),
+            JustifyContent::End => Length::zero(),
+            JustifyContent::FlexEnd => Length::zero(),
+            JustifyContent::Center => Length::zero(),
+            JustifyContent::Stretch => Length::zero(),
+            JustifyContent::SpaceBetween => free_space / (item_count - 1) as CSSFloat,
+            JustifyContent::SpaceAround => free_space / item_count as CSSFloat,
+            JustifyContent::SpaceEvenly => free_space / (item_count + 1) as CSSFloat,
         };
 
         // https://drafts.csswg.org/css-flexbox/#algo-cross-margins
diff --git a/tests/wpt/meta-legacy-layout/css/css-align/content-distribution/parse-align-content-001.html.ini b/tests/wpt/meta-legacy-layout/css/css-align/content-distribution/parse-align-content-001.html.ini
index 780fd8650f24..a486c8f2fd99 100644
--- a/tests/wpt/meta-legacy-layout/css/css-align/content-distribution/parse-align-content-001.html.ini
+++ b/tests/wpt/meta-legacy-layout/css/css-align/content-distribution/parse-align-content-001.html.ini
@@ -14,24 +14,14 @@
   [Checking align-content: last baseline]
     expected: FAIL
 
-  [Checking align-content: start]
-    expected: FAIL
-
   [Checking align-content: unsafe flex-start]
     expected: FAIL
 
   [Checking align-content: unsafe end]
     expected: FAIL
 
-  [Checking align-content: end]
-    expected: FAIL
-
-  [Checking align-content: space-evenly]
-    expected: FAIL
-
   [Checking align-content: safe center]
     expected: FAIL
 
   [Checking align-content: normal]
     expected: FAIL
-
diff --git a/tests/wpt/meta-legacy-layout/css/css-align/content-distribution/parse-align-content-003.html.ini b/tests/wpt/meta-legacy-layout/css/css-align/content-distribution/parse-align-content-003.html.ini
index 4137fe71ee4c..cae41d930860 100644
--- a/tests/wpt/meta-legacy-layout/css/css-align/content-distribution/parse-align-content-003.html.ini
+++ b/tests/wpt/meta-legacy-layout/css/css-align/content-distribution/parse-align-content-003.html.ini
@@ -14,24 +14,14 @@
   [Checking align-content: last baseline]
     expected: FAIL
 
-  [Checking align-content: start]
-    expected: FAIL
-
   [Checking align-content: unsafe flex-start]
     expected: FAIL
 
   [Checking align-content: unsafe end]
     expected: FAIL
 
-  [Checking align-content: end]
-    expected: FAIL
-
-  [Checking align-content: space-evenly]
-    expected: FAIL
-
   [Checking align-content: safe center]
     expected: FAIL
 
   [Checking align-content: normal]
     expected: FAIL
-
diff --git a/tests/wpt/meta-legacy-layout/css/css-align/content-distribution/parse-align-content-005.html.ini b/tests/wpt/meta-legacy-layout/css/css-align/content-distribution/parse-align-content-005.html.ini
index ecbb5dea0b36..b743419a2b30 100644
--- a/tests/wpt/meta-legacy-layout/css/css-align/content-distribution/parse-align-content-005.html.ini
+++ b/tests/wpt/meta-legacy-layout/css/css-align/content-distribution/parse-align-content-005.html.ini
@@ -1,10 +1,6 @@
 [parse-align-content-005.html]
-  [Test the value 'inherit' overrides current value ('end')]
-    expected: FAIL
-
   [Test the value 'inherit' overrides current value ('unsafe center')]
     expected: FAIL
 
   [Test the value 'inherit' overrides current value ('safe start')]
     expected: FAIL
-
diff --git a/tests/wpt/meta-legacy-layout/css/css-align/content-distribution/parse-justify-content-001.html.ini b/tests/wpt/meta-legacy-layout/css/css-align/content-distribution/parse-justify-content-001.html.ini
index e6271d20aac6..6e2757a39b08 100644
--- a/tests/wpt/meta-legacy-layout/css/css-align/content-distribution/parse-justify-content-001.html.ini
+++ b/tests/wpt/meta-legacy-layout/css/css-align/content-distribution/parse-justify-content-001.html.ini
@@ -1,13 +1,7 @@
 [parse-justify-content-001.html]
-  [Checking justify-content: start]
-    expected: FAIL
-
   [Checking justify-content: safe center]
     expected: FAIL
 
-  [Checking justify-content: end]
-    expected: FAIL
-
   [Checking justify-content: left]
     expected: FAIL
 
@@ -20,9 +14,6 @@
   [Checking justify-content: safe end]
     expected: FAIL
 
-  [Checking justify-content: space-evenly]
-    expected: FAIL
-
   [Checking justify-content: safe flex-end]
     expected: FAIL
 
@@ -31,4 +22,3 @@
 
   [Checking justify-content: unsafe end]
     expected: FAIL
-
diff --git a/tests/wpt/meta-legacy-layout/css/css-align/content-distribution/parse-justify-content-003.html.ini b/tests/wpt/meta-legacy-layout/css/css-align/content-distribution/parse-justify-content-003.html.ini
index 6df668c18a24..9fc2d0039f3a 100644
--- a/tests/wpt/meta-legacy-layout/css/css-align/content-distribution/parse-justify-content-003.html.ini
+++ b/tests/wpt/meta-legacy-layout/css/css-align/content-distribution/parse-justify-content-003.html.ini
@@ -1,13 +1,7 @@
 [parse-justify-content-003.html]
-  [Checking justify-content: start]
-    expected: FAIL
-
   [Checking justify-content: safe center]
     expected: FAIL
 
-  [Checking justify-content: end]
-    expected: FAIL
-
   [Checking justify-content: left]
     expected: FAIL
 
@@ -20,9 +14,6 @@
   [Checking justify-content: safe end]
     expected: FAIL
 
-  [Checking justify-content: space-evenly]
-    expected: FAIL
-
   [Checking justify-content: safe flex-end]
     expected: FAIL
 
@@ -31,4 +22,3 @@
 
   [Checking justify-content: unsafe end]
     expected: FAIL
-
diff --git a/tests/wpt/meta-legacy-layout/css/css-align/content-distribution/parse-justify-content-005.html.ini b/tests/wpt/meta-legacy-layout/css/css-align/content-distribution/parse-justify-content-005.html.ini
index 516032b7f3ac..7ab987526606 100644
--- a/tests/wpt/meta-legacy-layout/css/css-align/content-distribution/parse-justify-content-005.html.ini
+++ b/tests/wpt/meta-legacy-layout/css/css-align/content-distribution/parse-justify-content-005.html.ini
@@ -1,10 +1,6 @@
 [parse-justify-content-005.html]
-  [Test the value 'inherit' overrides current value ('end')]
-    expected: FAIL
-
   [Test the value 'inherit' overrides current value ('safe left')]
     expected: FAIL
 
   [Test the value 'inherit' overrides current value ('unsafe center')]
     expected: FAIL
-
diff --git a/tests/wpt/meta-legacy-layout/css/css-align/content-distribution/place-content-shorthand-004.html.ini b/tests/wpt/meta-legacy-layout/css/css-align/content-distribution/place-content-shorthand-004.html.ini
deleted file mode 100644
index 79ded4dc0b02..000000000000
--- a/tests/wpt/meta-legacy-layout/css/css-align/content-distribution/place-content-shorthand-004.html.ini
+++ /dev/null
@@ -1,22 +0,0 @@
-[place-content-shorthand-004.html]
-  [Verify fallback values are invalid]
-    expected: FAIL
-
-  [Verify numeric values are invalid]
-    expected: FAIL
-
-  [Verify 'auto' values are invalid]
-    expected: FAIL
-
-  [Verify self-position values are invalid]
-    expected: FAIL
-
-  [Verify <baseline-position> values are invalid for the justify-content property]
-    expected: FAIL
-
-  [Verify empty declaration is invalid]
-    expected: FAIL
-
-  [Verify 'left' and 'right' values are invalid for block/cross axis alignment]
-    expected: FAIL
-
diff --git a/tests/wpt/meta-legacy-layout/css/css-align/inheritance.html.ini b/tests/wpt/meta-legacy-layout/css/css-align/inheritance.html.ini
index 3c4206c1ae45..efe23207c848 100644
--- a/tests/wpt/meta-legacy-layout/css/css-align/inheritance.html.ini
+++ b/tests/wpt/meta-legacy-layout/css/css-align/inheritance.html.ini
@@ -17,9 +17,6 @@
   [Property justify-content has initial value normal]
     expected: FAIL
 
-  [Property justify-content does not inherit]
-    expected: FAIL
-
   [Property align-content does not inherit]
     expected: FAIL
 
@@ -46,4 +43,3 @@
 
   [Property column-gap does not inherit]
     expected: FAIL
-
diff --git a/tests/wpt/meta-legacy-layout/css/css-align/parsing/align-content-computed.html.ini b/tests/wpt/meta-legacy-layout/css/css-align/parsing/align-content-computed.html.ini
index 165bf87de0b0..6cc4974411e5 100644
--- a/tests/wpt/meta-legacy-layout/css/css-align/parsing/align-content-computed.html.ini
+++ b/tests/wpt/meta-legacy-layout/css/css-align/parsing/align-content-computed.html.ini
@@ -35,15 +35,5 @@
   [Property align-content value 'normal']
     expected: FAIL
 
-  [Property align-content value 'space-evenly']
-    expected: FAIL
-
   [Property align-content value 'safe flex-start']
     expected: FAIL
-
-  [Property align-content value 'start']
-    expected: FAIL
-
-  [Property align-content value 'end']
-    expected: FAIL
-
diff --git a/tests/wpt/meta-legacy-layout/css/css-align/parsing/align-content-valid.html.ini b/tests/wpt/meta-legacy-layout/css/css-align/parsing/align-content-valid.html.ini
index e6e43f8ee3f0..534aae829124 100644
--- a/tests/wpt/meta-legacy-layout/css/css-align/parsing/align-content-valid.html.ini
+++ b/tests/wpt/meta-legacy-layout/css/css-align/parsing/align-content-valid.html.ini
@@ -5,24 +5,14 @@
   [e.style['align-content'\] = "unsafe end" should set the property value]
     expected: FAIL
 
-  [e.style['align-content'\] = "end" should set the property value]
-    expected: FAIL
-
   [e.style['align-content'\] = "normal" should set the property value]
     expected: FAIL
 
   [e.style['align-content'\] = "baseline" should set the property value]
     expected: FAIL
 
-  [e.style['align-content'\] = "space-evenly" should set the property value]
-    expected: FAIL
-
-  [e.style['align-content'\] = "start" should set the property value]
-    expected: FAIL
-
   [e.style['align-content'\] = "safe flex-start" should set the property value]
     expected: FAIL
 
   [e.style['align-content'\] = "last baseline" should set the property value]
     expected: FAIL
-
diff --git a/tests/wpt/meta-legacy-layout/css/css-align/parsing/justify-content-computed.html.ini b/tests/wpt/meta-legacy-layout/css/css-align/parsing/justify-content-computed.html.ini
index 47abd3064e3e..de67d888a244 100644
--- a/tests/wpt/meta-legacy-layout/css/css-align/parsing/justify-content-computed.html.ini
+++ b/tests/wpt/meta-legacy-layout/css/css-align/parsing/justify-content-computed.html.ini
@@ -23,12 +23,6 @@
   [Property justify-content value 'safe flex-start' computes to 'safe flex-start']
     expected: FAIL
 
-  [Property justify-content value 'start']
-    expected: FAIL
-
-  [Property justify-content value 'end']
-    expected: FAIL
-
   [Property justify-content value 'unsafe end']
     expected: FAIL
 
@@ -41,9 +35,5 @@
   [Property justify-content value 'safe flex-start']
     expected: FAIL
 
-  [Property justify-content value 'space-evenly']
-    expected: FAIL
-
   [Property justify-content value 'left']
     expected: FAIL
-
diff --git a/tests/wpt/meta-legacy-layout/css/css-align/parsing/justify-content-valid.html.ini b/tests/wpt/meta-legacy-layout/css/css-align/parsing/justify-content-valid.html.ini
index 1e2f46660dd2..0fe3fef26837 100644
--- a/tests/wpt/meta-legacy-layout/css/css-align/parsing/justify-content-valid.html.ini
+++ b/tests/wpt/meta-legacy-layout/css/css-align/parsing/justify-content-valid.html.ini
@@ -2,24 +2,14 @@
   [e.style['justify-content'\] = "unsafe right" should set the property value]
     expected: FAIL
 
-  [e.style['justify-content'\] = "start" should set the property value]
-    expected: FAIL
-
   [e.style['justify-content'\] = "normal" should set the property value]
     expected: FAIL
 
   [e.style['justify-content'\] = "unsafe end" should set the property value]
     expected: FAIL
 
-  [e.style['justify-content'\] = "space-evenly" should set the property value]
-    expected: FAIL
-
-  [e.style['justify-content'\] = "end" should set the property value]
-    expected: FAIL
-
   [e.style['justify-content'\] = "safe flex-start" should set the property value]
     expected: FAIL
 
   [e.style['justify-content'\] = "left" should set the property value]
     expected: FAIL
-
diff --git a/tests/wpt/meta-legacy-layout/css/css-flexbox/align-content-wrap-005.html.ini b/tests/wpt/meta-legacy-layout/css/css-flexbox/align-content-wrap-005.html.ini
index 1dd468872d41..6bccebab78f3 100644
--- a/tests/wpt/meta-legacy-layout/css/css-flexbox/align-content-wrap-005.html.ini
+++ b/tests/wpt/meta-legacy-layout/css/css-flexbox/align-content-wrap-005.html.ini
@@ -5,9 +5,6 @@
   [.flexitem 2]
     expected: FAIL
 
-  [.flexitem 4]
-    expected: FAIL
-
   [.flexitem 5]
     expected: FAIL
 
diff --git a/tests/wpt/meta/css/css-flexbox/align-content-wrap-001.html.ini b/tests/wpt/meta/css/css-flexbox/align-content-wrap-001.html.ini
index f1a6baadd383..0dbcc6e6d137 100644
--- a/tests/wpt/meta/css/css-flexbox/align-content-wrap-001.html.ini
+++ b/tests/wpt/meta/css/css-flexbox/align-content-wrap-001.html.ini
@@ -7,15 +7,3 @@
 
   [.default, .verticalWriting 9]
     expected: FAIL
-
-  [.default, .verticalWriting 5]
-    expected: FAIL
-
-  [.default, .verticalWriting 6]
-    expected: FAIL
-
-  [.default, .verticalWriting 3]
-    expected: FAIL
-
-  [.default, .verticalWriting 2]
-    expected: FAIL
diff --git a/tests/wpt/meta/css/css-flexbox/align-content-wrap-003.html.ini b/tests/wpt/meta/css/css-flexbox/align-content-wrap-003.html.ini
index c3076b03f433..75af4a4f3e25 100644
--- a/tests/wpt/meta/css/css-flexbox/align-content-wrap-003.html.ini
+++ b/tests/wpt/meta/css/css-flexbox/align-content-wrap-003.html.ini
@@ -1,7 +1,4 @@
 [align-content-wrap-003.html]
-  [.flexbox 6]
-    expected: FAIL
-
   [.flexbox 1]
     expected: FAIL
 
@@ -11,12 +8,6 @@
   [.flexbox 8]
     expected: FAIL
 
-  [.flexbox 12]
-    expected: FAIL
-
-  [.flexbox 11]
-    expected: FAIL
-
   [.flexbox 34]
     expected: FAIL
 
@@ -59,12 +50,6 @@
   [.flexbox 22]
     expected: FAIL
 
-  [.flexbox 21]
-    expected: FAIL
-
-  [.flexbox 20]
-    expected: FAIL
-
   [.flexbox 44]
     expected: FAIL
 
diff --git a/tests/wpt/meta/css/css-flexbox/align-content-wrap-005.html.ini b/tests/wpt/meta/css/css-flexbox/align-content-wrap-005.html.ini
index 6bccebab78f3..c19c93543f24 100644
--- a/tests/wpt/meta/css/css-flexbox/align-content-wrap-005.html.ini
+++ b/tests/wpt/meta/css/css-flexbox/align-content-wrap-005.html.ini
@@ -5,6 +5,12 @@
   [.flexitem 2]
     expected: FAIL
 
+  [.flexitem 3]
+    expected: FAIL
+
+  [.flexitem 4]
+    expected: FAIL
+
   [.flexitem 5]
     expected: FAIL
 
diff --git a/tests/wpt/meta/css/css-flexbox/flexbox-justify-content-horiz-002.xhtml.ini b/tests/wpt/meta/css/css-flexbox/flexbox-justify-content-horiz-002.xhtml.ini
deleted file mode 100644
index 272354a198da..000000000000
--- a/tests/wpt/meta/css/css-flexbox/flexbox-justify-content-horiz-002.xhtml.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[flexbox-justify-content-horiz-002.xhtml]
-  expected: FAIL
diff --git a/tests/wpt/meta/css/css-flexbox/flexbox-justify-content-horiz-004.xhtml.ini b/tests/wpt/meta/css/css-flexbox/flexbox-justify-content-horiz-004.xhtml.ini
deleted file mode 100644
index 85bda5dda038..000000000000
--- a/tests/wpt/meta/css/css-flexbox/flexbox-justify-content-horiz-004.xhtml.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[flexbox-justify-content-horiz-004.xhtml]
-  expected: FAIL
diff --git a/tests/wpt/meta/css/css-flexbox/flexbox_justifycontent-rtl-001.html.ini b/tests/wpt/meta/css/css-flexbox/flexbox_justifycontent-rtl-001.html.ini
index 6829e9c0444c..81b7e481fea0 100644
--- a/tests/wpt/meta/css/css-flexbox/flexbox_justifycontent-rtl-001.html.ini
+++ b/tests/wpt/meta/css/css-flexbox/flexbox_justifycontent-rtl-001.html.ini
@@ -5,15 +5,15 @@
   [.container > div 2]
     expected: FAIL
 
-  [.container > div 4]
-    expected: FAIL
-
   [.container > div 5]
     expected: FAIL
 
   [.container > div 7]
     expected: FAIL
 
+  [.container > div 8]
+    expected: FAIL
+
   [.container > div 9]
     expected: FAIL
 
diff --git a/tests/wpt/meta/css/css-flexbox/flexbox_justifycontent-spacearound-negative.html.ini b/tests/wpt/meta/css/css-flexbox/flexbox_justifycontent-spacearound-negative.html.ini
deleted file mode 100644
index 6dc942b83b94..000000000000
--- a/tests/wpt/meta/css/css-flexbox/flexbox_justifycontent-spacearound-negative.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[flexbox_justifycontent-spacearound-negative.html]
-  expected: FAIL
diff --git a/tests/wpt/meta/css/css-flexbox/flexbox_justifycontent-spacebetween-negative.html.ini b/tests/wpt/meta/css/css-flexbox/flexbox_justifycontent-spacebetween-negative.html.ini
deleted file mode 100644
index d24cfe1c8bf7..000000000000
--- a/tests/wpt/meta/css/css-flexbox/flexbox_justifycontent-spacebetween-negative.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[flexbox_justifycontent-spacebetween-negative.html]
-  expected: FAIL
diff --git a/tests/wpt/meta/css/css-flexbox/flexbox_justifycontent-start-rtl.html.ini b/tests/wpt/meta/css/css-flexbox/flexbox_justifycontent-start-rtl.html.ini
deleted file mode 100644
index 4c4bce8a3463..000000000000
--- a/tests/wpt/meta/css/css-flexbox/flexbox_justifycontent-start-rtl.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[flexbox_justifycontent-start-rtl.html]
-  expected: FAIL
diff --git a/tests/wpt/meta/css/css-flexbox/flexbox_justifycontent-start.html.ini b/tests/wpt/meta/css/css-flexbox/flexbox_justifycontent-start.html.ini
deleted file mode 100644
index 95603d8cc873..000000000000
--- a/tests/wpt/meta/css/css-flexbox/flexbox_justifycontent-start.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[flexbox_justifycontent-start.html]
-  expected: FAIL