diff --git a/README.md b/README.md
index 568ad9d..b9cfa97 100644
--- a/README.md
+++ b/README.md
@@ -53,6 +53,7 @@ HISTORY
   * Add Compositing and Blending Level 1 features
   * Add CSS Fonts Module Level 3 features
   * Add CSS Speech Module features
+  * Add Selectors Level 4 features
   * Split CSS Counter Styles Level 3 features from `css3-lists.vim`
   * Follow spec updates
   * Add missing values
diff --git a/after/syntax/css/selectors4.vim b/after/syntax/css/selectors4.vim
new file mode 100644
index 0000000..a5ae1f3
--- /dev/null
+++ b/after/syntax/css/selectors4.vim
@@ -0,0 +1,5 @@
+syn match cssSelectorOp "[|]"
+syn match cssPseudoClassId contained "\<\(active\|valid\|invalid\)-drop-target\>"
+syn match cssPseudoClassId contained "\<placeholder-shown\>"
+syn match cssPseudoClassId contained "\<user-error\>"
+syn region cssPseudoClassLang matchgroup=cssPseudoClassId start=":dir(" end=")" oneline
diff --git a/after/syntax/html.vim b/after/syntax/html.vim
index cd7df2f..bf4e67a 100644
--- a/after/syntax/html.vim
+++ b/after/syntax/html.vim
@@ -41,3 +41,4 @@ syn include @htmlCss syntax/css/css-text-3.vim
 syn include @htmlCss syntax/css/css-text-decor-3.vim
 syn include @htmlCss syntax/css/css-variables.vim
 syn include @htmlCss syntax/css/css-writing-modes-3.vim
+syn include @htmlCss syntax/css/selectors4.vim
diff --git a/test/test.css b/test/test.css
index 29a72ce..439fba6 100644
--- a/test/test.css
+++ b/test/test.css
@@ -321,44 +321,54 @@
   ruby-position: ruby-base-container;
 }
 
-.selectors:not([DISABLED]),
-.selectors:matches(:hover, :focus),
-.selectors:any-link,
-.selectors:local-link,
-.selectors:local-link(0),
-.selectors:target,
-.selectors:scope,
-.selectors:current,
-.selectors:current(p, li, dt, dd),
-.selectors:past,
-.selectors:future,
-.selectors:enabled,
-.selectors:disabled,
-.selectors:checked,
-.selectors:indeterminate,
-.selectors:default,
-.selecors:in-range,
-.selectors:out-of-range,
-.selectors:required,
-.selectors:optional,
-.selectors:read-only,
-.selectors:read-write,
-.selectors:root,
-.selectors:empty,
-.selectors:nth-child(2n+1),
-.selectors:last-child,
-.selectors:nth-last-child(-n+2),
-.selectors:only-child,
-.selectors:first-of-type,
-.selectors:nth-of-type(2n+1),
-.selectors:last-of-type,
-.selectors:nth-last-of-type(n+2),
-.selectors:only-of-type,
-.selectors:nth-match(2n+1),
-.selectors:nth-last-match(-n+2),
-.selectors:column(p, li, dt, dd),
-.selectors:nth-column(2n+1),
-.selectors:nth-last-column(-n+2) {
+.selectors3:not([DISABLED]),
+.selectors3:matches(:hover, :focus),
+.selectors3:any-link,
+.selectors3:local-link,
+.selectors3:local-link(0),
+.selectors3:target,
+.selectors3:scope,
+.selectors3:current,
+.selectors3:current(p, li, dt, dd),
+.selectors3:past,
+.selectors3:future,
+.selectors3:enabled,
+.selectors3:disabled,
+.selectors3:checked,
+.selectors3:indeterminate,
+.selectors3:default,
+.selectors3:in-range,
+.selectors3:out-of-range,
+.selectors3:required,
+.selectors3:optional,
+.selectors3:read-only,
+.selectors3:read-write,
+.selectors3:root,
+.selectors3:empty,
+.selectors3:nth-child(2n+1),
+.selectors3:last-child,
+.selectors3:nth-last-child(-n+2),
+.selectors3:only-child,
+.selectors3:first-of-type,
+.selectors3:nth-of-type(2n+1),
+.selectors3:last-of-type,
+.selectors3:nth-last-of-type(n+2),
+.selectors3:only-of-type,
+.selectors3:nth-match(2n+1),
+.selectors3:nth-last-match(-n+2),
+.selectors3:column(p, li, dt, dd),
+.selectors3:nth-column(2n+1),
+.selectors3:nth-last-column(-n+2) {
+  display: auto;
+}
+
+foo | h1,
+.selectors4:dir(ltr),
+.selectors4:active-drop-target,
+.selectors4:valid-drop-target,
+.selectors4:invalid-drop-target,
+.selectors4:placeholder-shown,
+.selectors4:user-error {
   display: auto;
 }
 
diff --git a/test/test.html b/test/test.html
index 7d7515d..6d613c7 100644
--- a/test/test.html
+++ b/test/test.html
@@ -331,44 +331,54 @@
         ruby-position: ruby-base-container;
       }
 
-      .selectors:not([DISABLED]),
-      .selectors:matches(:hover, :focus),
-      .selectors:any-link,
-      .selectors:local-link,
-      .selectors:local-link(0),
-      .selectors:target,
-      .selectors:scope,
-      .selectors:current,
-      .selectors:current(p, li, dt, dd),
-      .selectors:past,
-      .selectors:future,
-      .selectors:enabled,
-      .selectors:disabled,
-      .selectors:checked,
-      .selectors:indeterminate,
-      .selectors:default,
-      .selecors:in-range,
-      .selectors:out-of-range,
-      .selectors:required,
-      .selectors:optional,
-      .selectors:read-only,
-      .selectors:read-write,
-      .selectors:root,
-      .selectors:empty,
-      .selectors:nth-child(2n+1),
-      .selectors:last-child,
-      .selectors:nth-last-child(-n+2),
-      .selectors:only-child,
-      .selectors:first-of-type,
-      .selectors:nth-of-type(2n+1),
-      .selectors:last-of-type,
-      .selectors:nth-last-of-type(n+2),
-      .selectors:only-of-type,
-      .selectors:nth-match(2n+1),
-      .selectors:nth-last-match(-n+2),
-      .selectors:column(p, li, dt, dd),
-      .selectors:nth-column(2n+1),
-      .selectors:nth-last-column(-n+2) {
+      .selectors3:not([DISABLED]),
+      .selectors3:matches(:hover, :focus),
+      .selectors3:any-link,
+      .selectors3:local-link,
+      .selectors3:local-link(0),
+      .selectors3:target,
+      .selectors3:scope,
+      .selectors3:current,
+      .selectors3:current(p, li, dt, dd),
+      .selectors3:past,
+      .selectors3:future,
+      .selectors3:enabled,
+      .selectors3:disabled,
+      .selectors3:checked,
+      .selectors3:indeterminate,
+      .selectors3:default,
+      .selectors3:in-range,
+      .selectors3:out-of-range,
+      .selectors3:required,
+      .selectors3:optional,
+      .selectors3:read-only,
+      .selectors3:read-write,
+      .selectors3:root,
+      .selectors3:empty,
+      .selectors3:nth-child(2n+1),
+      .selectors3:last-child,
+      .selectors3:nth-last-child(-n+2),
+      .selectors3:only-child,
+      .selectors3:first-of-type,
+      .selectors3:nth-of-type(2n+1),
+      .selectors3:last-of-type,
+      .selectors3:nth-last-of-type(n+2),
+      .selectors3:only-of-type,
+      .selectors3:nth-match(2n+1),
+      .selectors3:nth-last-match(-n+2),
+      .selectors3:column(p, li, dt, dd),
+      .selectors3:nth-column(2n+1),
+      .selectors3:nth-last-column(-n+2) {
+        display: auto;
+      }
+
+      foo | h1,
+      .selectors4:dir(ltr),
+      .selectors4:active-drop-target,
+      .selectors4:valid-drop-target,
+      .selectors4:invalid-drop-target,
+      .selectors4:placeholder-shown,
+      .selectors4:user-error {
         display: auto;
       }