diff --git a/docs/change-log.md b/docs/change-log.md
index a6b93ab2..f8d11ff1 100644
--- a/docs/change-log.md
+++ b/docs/change-log.md
@@ -69,6 +69,7 @@
 - docs: tweaks: ([#2104](https://github.com/MithrilJS/mithril.js/pull/2104) [@mikeyb](https://github.com/mikeyb), [#2205](https://github.com/MithrilJS/mithril.js/pull/2205), [@cavemansspa](https://github.com/cavemansspa), [#2265](https://github.com/MithrilJS/mithril.js/pull/2265), [@isiahmeadows](https://github.com/isiahmeadows))
 - render/core: avoid touching `Object.prototype.__proto__` setter with `key: "__proto__"` in certain situations ([#2251](https://github.com/MithrilJS/mithril.js/pull/2251))
 - render/core: Vnodes stored in the dom node supplied to `m.render()` are now normalized [#2266](https://github.com/MithrilJS/mithril.js/pull/2266)
+- render/core: CSS vars can now be specified in `{style}` attributes [#2192](https://github.com/MithrilJS/mithril.js/pull/2192)
 
 ---
 
diff --git a/render/render.js b/render/render.js
index 44ce338e..0b9322cf 100644
--- a/render/render.js
+++ b/render/render.js
@@ -776,16 +776,27 @@ module.exports = function($window) {
 	}
 
 	//style
-	function updateStyle(element, old, style) {
+	function updateStyle(element, old, input) {
+		if(typeof input === "object") {
+			var style = {}
+			for(var key in input) {
+				style[key] = String(input[key]).replace(/[A-Z]/g, function(capital){
+					return "-" + capital.toLowerCase()
+				})
+			}
+		}
+		else {
+			var style = input
+		}
 		if (old != null && style != null && typeof old === "object" && typeof style === "object" && style !== old) {
 			// Both old & new are (different) objects.
 			// Update style properties that have changed
 			for (var key in style) {
-				if (style[key] !== old[key]) element.style[key] = style[key]
+				if (style[key] !== old[key]) element.style.setProperty(key, style[key])
 			}
 			// Remove style properties that no longer exist
 			for (var key in old) {
-				if (!(key in style)) element.style[key] = ""
+				if (!(key in style)) element.style.removeProperty(key)
 			}
 			return
 		}
@@ -795,7 +806,7 @@ module.exports = function($window) {
 		else {
 			if (typeof old === "string") element.style.cssText = ""
 			for (var key in style) {
-				element.style[key] = style[key]
+				element.style.setProperty(key, style[key])
 			}
 		}
 	}
diff --git a/render/tests/test-updateElement.js b/render/tests/test-updateElement.js
index 8a190a4c..c1eb573f 100644
--- a/render/tests/test-updateElement.js
+++ b/render/tests/test-updateElement.js
@@ -179,19 +179,6 @@ o.spec("updateElement", function() {
 		o(updated.dom.style.backgroundColor).equals("red")
 		o(updated.dom.style.border).equals("")
 	})
-	o("updates style when it's same object but mutated", function() {
-		var style = {backgroundColor: "red", color: "gold"}
-		var vnode = {tag: "a", attrs: {style: style}}
-
-		render(root, [vnode])
-
-		delete style.backgroundColor
-		var updated = {tag: "a", attrs: {style: style}}
-		render(root, [updated])
-
-		o(updated.dom.style.backgroundColor).equals("")
-		o(updated.dom.style.color).equals("gold")
-	})
 	o("does not re-render element styles for equivalent style objects", function() {
 		var style = {color: "gold"}
 		var vnode = {tag: "a", attrs: {style: style}}
diff --git a/test-utils/domMock.js b/test-utils/domMock.js
index ce494683..e811c4e7 100644
--- a/test-utils/domMock.js
+++ b/test-utils/domMock.js
@@ -227,29 +227,40 @@ module.exports = function(options) {
 			createElement: function(tag) {
 				var cssText = ""
 				var style = {}
-				Object.defineProperty(style, "cssText", {
-					get: function() {return cssText},
-					set: function (value) {
-						var buf = []
-						if (typeof value === "string") {
-							for (var key in style) style[key] = ""
-							var rules = splitDeclList(value)
-							for (var i = 0; i < rules.length; i++) {
-								var rule = rules[i]
-								var colonIndex = rule.indexOf(":")
-								if (colonIndex > -1) {
-									var rawKey = rule.slice(0, colonIndex).trim()
-									var key = rawKey.replace(/-\D/g, function(match) {return match[1].toUpperCase()})
-									var value = rule.slice(colonIndex + 1).trim()
-									if (key !== "cssText") {
-										style[key] = value
-										buf.push(rawKey + ": " + value + ";")
+				Object.defineProperties(style, {
+					cssText: {
+						get: function() {return cssText},
+						set: function (value) {
+							var buf = []
+							if (typeof value === "string") {
+								for (var key in style) style[key] = ""
+								var rules = splitDeclList(value)
+								for (var i = 0; i < rules.length; i++) {
+									var rule = rules[i]
+									var colonIndex = rule.indexOf(":")
+									if (colonIndex > -1) {
+										var rawKey = rule.slice(0, colonIndex).trim()
+										var key = rawKey.replace(/-\D/g, function(match) {return match[1].toUpperCase()})
+										var value = rule.slice(colonIndex + 1).trim()
+										if (key !== "cssText") {
+											style[key] = value
+											buf.push(rawKey + ": " + value + ";")
+										}
 									}
 								}
+								element.setAttribute("style", cssText = buf.join(" "))
 							}
-							element.setAttribute("style", cssText = buf.join(" "))
 						}
-					}
+					},
+					getPropertyValue: {value: function(key){
+						return style[key]
+					}},
+					removeProperty: {value: function(key){
+						style[key] = ""
+					}},
+					setProperty: {value: function(key, value){
+						style[key] = value
+					}}
 				})
 				var events = {}
 				var element = {