new file mode 100644
--- /dev/null
+++ b/testing/web-platform/meta/css/css-scoping-1/__dir__.ini
@@ -0,0 +1,1 @@
+prefs: [dom.webcomponents.enabled:true]

deleted file mode 100644
--- a/testing/web-platform/meta/css/css-scoping-1/css-scoping-shadow-assigned-node-with-rules.html.ini
+++ /dev/null
@@ -1,3 +0,0 @@
-[css-scoping-shadow-assigned-node-with-rules.html]
-  type: reftest
-  expected: FAIL

deleted file mode 100644
--- a/testing/web-platform/meta/css/css-scoping-1/css-scoping-shadow-host-with-before-after.html.ini
+++ /dev/null
@@ -1,3 +0,0 @@
-[css-scoping-shadow-host-with-before-after.html]
-  type: reftest
-  expected: FAIL

deleted file mode 100644
--- a/testing/web-platform/meta/css/css-scoping-1/css-scoping-shadow-root-hides-children.html.ini
+++ /dev/null
@@ -1,3 +0,0 @@
-[css-scoping-shadow-root-hides-children.html]
-  type: reftest
-  expected: FAIL

deleted file mode 100644
--- a/testing/web-platform/meta/css/css-scoping-1/css-scoping-shadow-slotted-rule.html.ini
+++ /dev/null
@@ -1,3 +0,0 @@
-[css-scoping-shadow-slotted-rule.html]
-  type: reftest
-  expected: FAIL

deleted file mode 100644
--- a/testing/web-platform/meta/css/css-scoping-1/css-scoping-shadow-with-outside-rules.html.ini
+++ /dev/null
@@ -1,3 +0,0 @@
-[css-scoping-shadow-with-outside-rules.html]
-  type: reftest
-  expected: FAIL

deleted file mode 100644
--- a/testing/web-platform/meta/css/css-scoping-1/css-scoping-shadow-with-rules-no-style-leak.html.ini
+++ /dev/null
@@ -1,3 +0,0 @@
-[css-scoping-shadow-with-rules-no-style-leak.html]
-  type: reftest
-  expected: FAIL

deleted file mode 100644
--- a/testing/web-platform/meta/css/css-scoping-1/css-scoping-shadow-with-rules.html.ini
+++ /dev/null
@@ -1,3 +0,0 @@
-[css-scoping-shadow-with-rules.html]
-  type: reftest
-  expected: FAIL

--- a/testing/web-platform/meta/css/css-scoping-1/shadow-cascade-order-001.html.ini
+++ b/testing/web-platform/meta/css/css-scoping-1/shadow-cascade-order-001.html.ini
@@ -1,5 +1,110 @@
 [shadow-cascade-order-001.html]
   type: testharness
-  [Shadow DOM: CSS Style Rule cascading]
+  [A4. ::slotted vs :host, earlier in tree-of-trees rule should win for open mode.]
+    expected: FAIL
+
+  [B4. ::slotted  with !important vs :host, earlier in tree-of-trees rule should win for open mode.]
+    expected: FAIL
+
+  [B5. ::slotted vs inline with !important, inline rule should win for open mode.]
+    expected: FAIL
+
+  [C1. document vs ::slotted with !important, ::slotted rule should win for open mode.]
+    expected: FAIL
+
+  [C2. document vs :host with !important, :host rule should win for open mode.]
+    expected: FAIL
+
+  [C4. ::slotted vs :host with !important, later in tree-of-trees rule should win for open mode.]
+    expected: FAIL
+
+  [C5. ::slotted with !important vs inline, ::slotted rule should win for open mode.]
+    expected: FAIL
+
+  [C6. :host with !important vs inline, :host rule should win for open mode.]
+    expected: FAIL
+
+  [D1. document vs ::slotted both with !important, ::slotted rule should win for open mode.]
+    expected: FAIL
+
+  [D2. document vs :host both with !important, :host rule should win for open mode.]
+    expected: FAIL
+
+  [D4. ::slotted vs :host both with !important, later in tree-of-trees rule should win for open mode.]
+    expected: FAIL
+
+  [D5. ::slotted vs inline both with !important, ::slotted rule should win for open mode.]
+    expected: FAIL
+
+  [D6. :host vs inline both with !important, :host rule should win for open mode.]
+    expected: FAIL
+
+  [E2. all styles with !important applied, rule in the last tree-of-trees should win for open mode.]
+    expected: FAIL
+
+  [F3. document vs ::slotted with !important, important rule should win for open mode.]
+    expected: FAIL
+
+  [F4. document vs ::slotted with !important, important rule should win for open mode.]
+    expected: FAIL
+
+  [F5. document vs :host with !important, important rule should win for open mode.]
+    expected: FAIL
+
+  [F6. all rules with !important, the last rule in tree-of-trees should win for open mode.]
     expected: FAIL
 
+  [A4. ::slotted vs :host, earlier in tree-of-trees rule should win for closed mode.]
+    expected: FAIL
+
+  [B4. ::slotted  with !important vs :host, earlier in tree-of-trees rule should win for closed mode.]
+    expected: FAIL
+
+  [B5. ::slotted vs inline with !important, inline rule should win for closed mode.]
+    expected: FAIL
+
+  [C1. document vs ::slotted with !important, ::slotted rule should win for closed mode.]
+    expected: FAIL
+
+  [C2. document vs :host with !important, :host rule should win for closed mode.]
+    expected: FAIL
+
+  [C4. ::slotted vs :host with !important, later in tree-of-trees rule should win for closed mode.]
+    expected: FAIL
+
+  [C5. ::slotted with !important vs inline, ::slotted rule should win for closed mode.]
+    expected: FAIL
+
+  [C6. :host with !important vs inline, :host rule should win for closed mode.]
+    expected: FAIL
+
+  [D1. document vs ::slotted both with !important, ::slotted rule should win for closed mode.]
+    expected: FAIL
+
+  [D2. document vs :host both with !important, :host rule should win for closed mode.]
+    expected: FAIL
+
+  [D4. ::slotted vs :host both with !important, later in tree-of-trees rule should win for closed mode.]
+    expected: FAIL
+
+  [D5. ::slotted vs inline both with !important, ::slotted rule should win for closed mode.]
+    expected: FAIL
+
+  [D6. :host vs inline both with !important, :host rule should win for closed mode.]
+    expected: FAIL
+
+  [E2. all styles with !important applied, rule in the last tree-of-trees should win for closed mode.]
+    expected: FAIL
+
+  [F3. document vs ::slotted with !important, important rule should win for closed mode.]
+    expected: FAIL
+
+  [F4. document vs ::slotted with !important, important rule should win for closed mode.]
+    expected: FAIL
+
+  [F5. document vs :host with !important, important rule should win for closed mode.]
+    expected: FAIL
+
+  [F6. all rules with !important, the last rule in tree-of-trees should win for closed mode.]
+    expected: FAIL
+

new file mode 100644
--- /dev/null
+++ b/testing/web-platform/meta/css/selectors4/__dir__.ini
@@ -0,0 +1,1 @@
+prefs: [dom.webcomponents.enabled:true]

--- a/testing/web-platform/meta/css/selectors4/focus-within-shadow-001.html.ini
+++ b/testing/web-platform/meta/css/selectors4/focus-within-shadow-001.html.ini
@@ -1,3 +1,3 @@
 [focus-within-shadow-001.html]
   type: reftest
-  expected: TIMEOUT
+  expected: FAIL

deleted file mode 100644
--- a/testing/web-platform/meta/css/selectors4/focus-within-shadow-002.html.ini
+++ /dev/null
@@ -1,3 +0,0 @@
-[focus-within-shadow-002.html]
-  type: reftest
-  expected: TIMEOUT

deleted file mode 100644
--- a/testing/web-platform/meta/css/selectors4/focus-within-shadow-003.html.ini
+++ /dev/null
@@ -1,3 +0,0 @@
-[focus-within-shadow-003.html]
-  type: reftest
-  expected: TIMEOUT

deleted file mode 100644
--- a/testing/web-platform/meta/css/selectors4/focus-within-shadow-004.html.ini
+++ /dev/null
@@ -1,3 +0,0 @@
-[focus-within-shadow-004.html]
-  type: reftest
-  expected: TIMEOUT

deleted file mode 100644
--- a/testing/web-platform/meta/css/selectors4/focus-within-shadow-005.html.ini
+++ /dev/null
@@ -1,3 +0,0 @@
-[focus-within-shadow-005.html]
-  type: reftest
-  expected: TIMEOUT

--- a/testing/web-platform/meta/css/selectors4/focus-within-shadow-006.html.ini
+++ b/testing/web-platform/meta/css/selectors4/focus-within-shadow-006.html.ini
@@ -1,3 +1,3 @@
 [focus-within-shadow-006.html]
   type: reftest
-  expected: TIMEOUT
+  expected: FAIL