diff --git a/CHANGELOG.md b/CHANGELOG.md
index a8976db..ff788d8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,15 @@
 
 ## main
 
+
+#### :boom: Breaking Change
+
+- Corrected return type of `getPropertyValue` for CSS style attributes (it's nullable and now returns an option).
+
+#### :bug: Bug Fix
+
+- Widened input type of `Window.getComputedStyle`, allowing subclasses of Element (such as HtmlElement).
+
 # 0.9.1
 
 #### :bug: Bug Fix
diff --git a/lib/js/tests/Webapi/Dom/Webapi__Dom__Window__test.js b/lib/js/tests/Webapi/Dom/Webapi__Dom__Window__test.js
index 7505533..abddaf1 100644
--- a/lib/js/tests/Webapi/Dom/Webapi__Dom__Window__test.js
+++ b/lib/js/tests/Webapi/Dom/Webapi__Dom__Window__test.js
@@ -33,6 +33,10 @@ window.focus();
 
 window.getComputedStyle(el);
 
+window.getComputedStyle(el);
+
+window.getComputedStyle(el, "hover");
+
 window.getComputedStyle(el, "hover");
 
 window.getSelection();
@@ -83,7 +87,10 @@ window.onload = (function (param) {
     console.log("load");
   });
 
+var htmlEl = el;
+
 exports.el = el;
+exports.htmlEl = htmlEl;
 exports.$$event = $$event;
 exports.handleClick = handleClick;
 exports.idleId = idleId;
diff --git a/src/Webapi/Dom/Webapi__Dom__CssStyleDeclaration.res b/src/Webapi/Dom/Webapi__Dom__CssStyleDeclaration.res
index 8a1065a..a9af97a 100644
--- a/src/Webapi/Dom/Webapi__Dom__CssStyleDeclaration.res
+++ b/src/Webapi/Dom/Webapi__Dom__CssStyleDeclaration.res
@@ -7,7 +7,8 @@ type cssRule /* TODO: Move to Webapi__Dom */
 @get external parentRule: t => cssRule = "parentRule"
 
 @send external getPropertyPriority: (t, string) => string = "getPropertyPriority"
-@send external getPropertyValue: (t, string) => string = "getPropertyValue"
+@send @return(nullable)
+external getPropertyValue: (t, string) => option<string> = "getPropertyValue"
 @send external item: (t, int) => string = "item"
 @send external removeProperty: (t, string) => string = "removeProperty"
 @send external setProperty: (t, string, string, string) => unit = "setProperty"
@@ -135,4 +136,4 @@ type cssRule /* TODO: Move to Webapi__Dom */
 @get external widows: t => string = "widows"
 @get external width: t => string = "width"
 @get external wordSpacing: t => string = "wordSpacing"
-@get external zIndex: t => string = "zIndex"
+@get external zIndex: t => string = "zIndex"
\ No newline at end of file
diff --git a/src/Webapi/Dom/Webapi__Dom__Window.res b/src/Webapi/Dom/Webapi__Dom__Window.res
index 5517271..02e510a 100644
--- a/src/Webapi/Dom/Webapi__Dom__Window.res
+++ b/src/Webapi/Dom/Webapi__Dom__Window.res
@@ -78,11 +78,13 @@ module Impl = (
   @send external close: t_window => unit = "close"
   @send external confirm: (t_window, string) => bool = "confirm"
   @send external focus: t_window => unit = "focus"
-  @send external getComputedStyle: (t_window, Dom.element) => Dom.cssStyleDeclaration = "getComputedStyle"
+  @send
+  external getComputedStyle: (t_window, Dom.element_like<'a>) => Dom.cssStyleDeclaration =
+    "getComputedStyle"
   @send
   external getComputedStyleWithPseudoElement: (
     t_window,
-    Dom.element,
+    Dom.element_like<'a>,
     string,
   ) => Dom.cssStyleDeclaration = "getComputedStyle"
   @send @return(nullable) external getSelection: t_window => option<Dom.selection> = "getSelection"
diff --git a/tests/Webapi/Dom/Webapi__Dom__Window__test.res b/tests/Webapi/Dom/Webapi__Dom__Window__test.res
index b52f601..8f743bc 100644
--- a/tests/Webapi/Dom/Webapi__Dom__Window__test.res
+++ b/tests/Webapi/Dom/Webapi__Dom__Window__test.res
@@ -1,6 +1,7 @@
 open Webapi.Dom
 
 let el = document->Document.createElement("strong")
+let htmlEl = el->Element.unsafeAsHtmlElement
 let event = document->Document.createEvent("my-event")
 let handleClick = _ => print_endline("asd")
 
@@ -53,7 +54,9 @@ Window.close(window)
 let _ = window->Window.confirm("is ok?")
 Window.focus(window)
 let _ = window->Window.getComputedStyle(el)
+let _ = window->Window.getComputedStyle(htmlEl)
 let _ = window->Window.getComputedStyleWithPseudoElement(el, "hover")
+let _ = window->Window.getComputedStyleWithPseudoElement(htmlEl, "hover")
 let _ = Window.getSelection(window)
 let _ = window->Window.matchMedia("max-height: 400")
 let _ = window->Window.moveBy(10, -10)