diff --git a/src/vs/workbench/browser/parts/editor/media/notabstitlecontrol.css b/src/vs/workbench/browser/parts/editor/media/notabstitlecontrol.css
index 6331cd7281bb0d6885131efecdf29685e41e1c17..28760657fbafb5daea06ad162f6246295ed07ae1 100644
--- a/src/vs/workbench/browser/parts/editor/media/notabstitlecontrol.css
+++ b/src/vs/workbench/browser/parts/editor/media/notabstitlecontrol.css
@@ -54,7 +54,7 @@
 	background-image: none;
 }
 
-.monaco-workbench.windows > .part.editor > .content .editor-group-container > .title.breadcrumbs .breadcrumbs-control .monaco-breadcrumb-item::before  {
+.windows > .monaco-workbench > .part.editor > .content .editor-group-container > .title.breadcrumbs .breadcrumbs-control .monaco-breadcrumb-item::before  {
 	content: '\\';
 }
 
diff --git a/src/vs/workbench/browser/parts/titlebar/media/titlebarpart.css b/src/vs/workbench/browser/parts/titlebar/media/titlebarpart.css
index 6a0f061d4dc52612bbcbdb31674b6aaa48da2362..8514900328393a69bc6d6677260e7933d1dc8b22 100644
--- a/src/vs/workbench/browser/parts/titlebar/media/titlebarpart.css
+++ b/src/vs/workbench/browser/parts/titlebar/media/titlebarpart.css
@@ -42,8 +42,8 @@
 
 /* Windows/Linux: Rules for custom title (icon, window controls)  */
 
-.monaco-workbench.windows > .part.titlebar,
-.monaco-workbench.linux > .part.titlebar {
+.windows > .monaco-workbench > .part.titlebar,
+.linux > .monaco-workbench > .part.titlebar {
 	padding: 0;
 	height: 30px;
 	line-height: 30px;
@@ -51,17 +51,17 @@
 	overflow: visible;
 }
 
-.monaco-workbench.windows > .part.titlebar > .window-title,
-.monaco-workbench.linux > .part.titlebar > .window-title {
+.windows > .monaco-workbench > .part.titlebar > .window-title,
+.linux > .monaco-workbench > .part.titlebar > .window-title {
 	cursor: default;
 }
 
-.monaco-workbench.linux > .part.titlebar > .window-title {
+.linux > .monaco-workbench > .part.titlebar > .window-title {
 	font-size: inherit;
 }
 
-.monaco-workbench.windows > .part.titlebar > .resizer,
-.monaco-workbench.linux > .part.titlebar > .resizer {
+.windows > .monaco-workbench > .part.titlebar > .resizer,
+.linux > .monaco-workbench > .part.titlebar > .resizer {
 	-webkit-app-region: no-drag;
 	position: absolute;
 	top: 0;
@@ -69,8 +69,8 @@
 	height: 20%;
 }
 
-.monaco-workbench.windows.fullscreen > .part.titlebar > .resizer,
-.monaco-workbench.linux.fullscreen > .part.titlebar > .resizer {
+.windows > .monaco-workbench.fullscreen > .part.titlebar > .resizer,
+.linux > .monaco-workbench.fullscreen > .part.titlebar > .resizer {
 	display: none;
 }
 
@@ -156,4 +156,4 @@
 
 .monaco-workbench > .part.titlebar > .window-controls-container .window-icon.window-close:hover {
 	background-color: white;
-}
\ No newline at end of file
+}
diff --git a/src/vs/workbench/electron-browser/workbench.ts b/src/vs/workbench/electron-browser/workbench.ts
index e7eea355c121bda832bd9c488e8a00c70a627b4c..586a866c7b882802ac558c0a41adbde308a877e1 100644
--- a/src/vs/workbench/electron-browser/workbench.ts
+++ b/src/vs/workbench/electron-browser/workbench.ts
@@ -292,7 +292,7 @@ export class Workbench extends Disposable implements IPartService {
 	private createWorkbench(): void {
 		this.workbench = document.createElement('div');
 		this.workbench.id = Identifiers.WORKBENCH_CONTAINER;
-		DOM.addClasses(this.workbench, 'monaco-workbench', isWindows ? 'windows' : isLinux ? 'linux' : 'mac');
+		DOM.addClass(this.workbench, 'monaco-workbench');
 
 		this._register(DOM.addDisposableListener(this.workbench, DOM.EventType.SCROLL, () => {
 			this.workbench.scrollTop = 0; // Prevent workbench from scrolling #55456
diff --git a/src/vs/workbench/parts/debug/browser/media/debug.contribution.css b/src/vs/workbench/parts/debug/browser/media/debug.contribution.css
index 264cfcb3b0784bc35076329973c60e54a831828f..330f9e8a0b9b50a7b91f78c8af5aec112cbfca11 100644
--- a/src/vs/workbench/parts/debug/browser/media/debug.contribution.css
+++ b/src/vs/workbench/parts/debug/browser/media/debug.contribution.css
@@ -142,12 +142,12 @@
 	font-family: Monaco, Menlo, Consolas, "Droid Sans Mono", "Inconsolata", "Courier New", monospace, "Droid Sans Fallback";
 }
 
-.monaco-workbench.mac .monaco-list-row .expression {
+.mac > .monaco-workbench .monaco-list-row .expression {
 	font-size: 11px;
 }
 
-.monaco-workbench.windows .monaco-list-row .expression,
-.monaco-workbench.linux .monaco-list-row .expression {
+.windows > .monaco-workbench .monaco-list-row .expression,
+.linux > .monaco-workbench .monaco-list-row .expression {
 	font-size: 13px;
 }
 
diff --git a/src/vs/workbench/parts/debug/browser/media/debugViewlet.css b/src/vs/workbench/parts/debug/browser/media/debugViewlet.css
index c44526f401c1dc8f77fc12116e624878333ba1f8..38b36067f54557ce75937f87336ecc25a499c8cf 100644
--- a/src/vs/workbench/parts/debug/browser/media/debugViewlet.css
+++ b/src/vs/workbench/parts/debug/browser/media/debugViewlet.css
@@ -64,7 +64,7 @@
 	margin-top: 7px;
 }
 
-.monaco-workbench.mac > .part > .title > .title-actions .start-debug-action-item {
+.mac > .monaco-workbench > .part > .title > .title-actions .start-debug-action-item {
 	border-radius: 4px;
 }
 
diff --git a/src/vs/workbench/parts/debug/browser/media/exceptionWidget.css b/src/vs/workbench/parts/debug/browser/media/exceptionWidget.css
index 420b53219ad4559a75c2e1b7ef5aeee630a62bf1..5ddc57325e88aadc2a3e6e3a5030a2837b8a915c 100644
--- a/src/vs/workbench/parts/debug/browser/media/exceptionWidget.css
+++ b/src/vs/workbench/parts/debug/browser/media/exceptionWidget.css
@@ -33,11 +33,11 @@
 
 /* High Contrast Theming */
 
-.monaco-workbench.mac .zone-widget .zone-widget-container.exception-widget {
+.mac > .monaco-workbench .zone-widget .zone-widget-container.exception-widget {
 	font-size: 11px;
 }
 
-.monaco-workbench.windows .zone-widget .zone-widget-container.exception-widget,
-.monaco-workbench.linux .zone-widget .zone-widget-container.exception-widget {
+.windows > .monaco-workbench .zone-widget .zone-widget-container.exception-widget,
+.linux > .monaco-workbench .zone-widget .zone-widget-container.exception-widget {
 	font-size: 13px;
 }
diff --git a/src/vs/workbench/parts/debug/browser/media/repl.css b/src/vs/workbench/parts/debug/browser/media/repl.css
index a1fde30cbfe13b19d1fe47d06e92b0fcad29f093..4dc5eff0dead588d35bf2d84cfa0a92173b3d407 100644
--- a/src/vs/workbench/parts/debug/browser/media/repl.css
+++ b/src/vs/workbench/parts/debug/browser/media/repl.css
@@ -37,13 +37,13 @@
 	word-break: break-all;
 }
 
-.monaco-workbench.mac .repl .repl-tree .monaco-tl-twistie.collapsible + .monaco-tl-contents,
-.monaco-workbench.mac .repl .repl-tree .monaco-tl-twistie {
+.mac > .monaco-workbench .repl .repl-tree .monaco-tl-twistie.collapsible + .monaco-tl-contents,
+.mac > .monaco-workbench .repl .repl-tree .monaco-tl-twistie {
 	cursor: pointer;
 }
 
-.monaco-workbench.mac .repl .repl-tree .input.expression,
-.monaco-workbench.mac .repl .repl-tree .output.expression {
+.mac > .monaco-workbench .repl .repl-tree .input.expression,
+.mac > .monaco-workbench .repl .repl-tree .output.expression {
 	font-size: 12px;
 }
 
@@ -62,10 +62,10 @@
 	text-decoration: underline;
 }
 
-.monaco-workbench.windows .repl .repl-tree .monaco-list-row .input.expression,
-.monaco-workbench.windows .repl .repl-tree .monaco-list-row .output.expression,
-.monaco-workbench.linux .repl .repl-tree .monaco-list-row .input.expression,
-.monaco-workbench.linux .repl .repl-tree .monaco-list-row .output.expression {
+.windows > .monaco-workbench .repl .repl-tree .monaco-list-row .input.expression,
+.windows > .monaco-workbench .repl .repl-tree .monaco-list-row .output.expression,
+.linux > .monaco-workbench .repl .repl-tree .monaco-list-row .input.expression,
+.linux > .monaco-workbench .repl .repl-tree .monaco-list-row .output.expression {
 	font-size: 14px;
 }
 
@@ -103,7 +103,7 @@
 	line-height: 18px;
 }
 
-.monaco-workbench.linux .repl .repl-input-wrapper:before {
+.linux > .monaco-workbench .repl .repl-input-wrapper:before {
 	font-size: 9px;
 }
 
diff --git a/src/vs/workbench/parts/files/electron-browser/media/explorerviewlet.css b/src/vs/workbench/parts/files/electron-browser/media/explorerviewlet.css
index c3fc2504f7076250e24d7ee612cac1d9dfe38c77..b5569536e3e07bdc60758c31f6421eb200a69391 100644
--- a/src/vs/workbench/parts/files/electron-browser/media/explorerviewlet.css
+++ b/src/vs/workbench/parts/files/electron-browser/media/explorerviewlet.css
@@ -106,8 +106,8 @@
 	line-height: normal;
 }
 
-.monaco-workbench.linux .explorer-viewlet .explorer-item .monaco-inputbox,
-.monaco-workbench.mac .explorer-viewlet .explorer-item .monaco-inputbox {
+.linux > .monaco-workbench .explorer-viewlet .explorer-item .monaco-inputbox,
+.mac > .monaco-workbench .explorer-viewlet .explorer-item .monaco-inputbox {
 	height: 22px;
 }
 
@@ -115,8 +115,8 @@
 	padding: 1px 2px;
 }
 
-.monaco-workbench.linux .explorer-viewlet .explorer-item .monaco-inputbox > .wrapper > .input,
-.monaco-workbench.mac .explorer-viewlet .explorer-item .monaco-inputbox > .wrapper > .input {
+.linux > .monaco-workbench .explorer-viewlet .explorer-item .monaco-inputbox > .wrapper > .input,
+.mac > .monaco-workbench .explorer-viewlet .explorer-item .monaco-inputbox > .wrapper > .input {
 	padding: 0;
 	height: 20px;
 }
diff --git a/src/vs/workbench/parts/terminal/electron-browser/media/terminal.css b/src/vs/workbench/parts/terminal/electron-browser/media/terminal.css
index c5da665535ef6360963cac0d87aaf196ca320328..74e79a263ed1b615fc68d32f2c53d93df9c90df8 100644
--- a/src/vs/workbench/parts/terminal/electron-browser/media/terminal.css
+++ b/src/vs/workbench/parts/terminal/electron-browser/media/terminal.css
@@ -157,8 +157,8 @@
 .vs-dark .monaco-workbench .terminal-action.split, .hc-black .monaco-workbench .terminal-action.split { background: url('split-inverse.svg') center center no-repeat; }
 .vs-dark .monaco-workbench .panel.right .terminal-action.split, .hc-black .monaco-workbench .panel.right .terminal-action.split { background: url('split-horizontal-inverse.svg') center center no-repeat; }
 
-.vs-dark .monaco-workbench.mac .panel.integrated-terminal .terminal-outer-container:not(.alt-active) .terminal:not(.enable-mouse-events),
-.hc-black .monaco-workbench.mac .panel.integrated-terminal .terminal-outer-container:not(.alt-active) .terminal:not(.enable-mouse-events) {
+.vs-dark.mac .monaco-workbench .panel.integrated-terminal .terminal-outer-container:not(.alt-active) .terminal:not(.enable-mouse-events),
+.hc-black.mac .monaco-workbench .panel.integrated-terminal .terminal-outer-container:not(.alt-active) .terminal:not(.enable-mouse-events) {
 	cursor: -webkit-image-set(url('data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAQAAAC1+jfqAAAAL0lEQVQoz2NgCD3x//9/BhBYBWdhgFVAiVW4JBFKGIa4AqD0//9D3pt4I4tAdAMAHTQ/j5Zom30AAAAASUVORK5CYII=') 1x, url('data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAACAAAAAgCAQAAADZc7J/AAAAz0lEQVRIx2NgYGBY/R8I/vx5eelX3n82IJ9FxGf6tksvf/8FiTMQAcAGQMDvSwu09abffY8QYSAScNk45G198eX//yev73/4///701eh//kZSARckrNBRvz//+8+6ZohwCzjGNjdgQxkAg7B9WADeBjIBqtJCbhRA0YNoIkBSNmaPEMoNmA0FkYNoFKhapJ6FGyAH3nauaSmPfwI0v/3OukVi0CIZ+F25KrtYcx/CTIy0e+rC7R1Z4KMICVTQQ14feVXIbR695u14+Ir4gwAAD49E54wc1kWAAAAAElFTkSuQmCC') 2x) 5 8, text;
 }
 
diff --git a/src/vs/workbench/parts/watermark/electron-browser/watermark.css b/src/vs/workbench/parts/watermark/electron-browser/watermark.css
index 8742bbe9d8dc67dae1935204c09275665bc0fab9..9875886f6525c92bdfcde7d69609727bda87a800 100644
--- a/src/vs/workbench/parts/watermark/electron-browser/watermark.css
+++ b/src/vs/workbench/parts/watermark/electron-browser/watermark.css
@@ -55,7 +55,7 @@
 	padding-right: 0.5em;
 }
 
-.monaco-workbench.mac > .part.editor > .content.empty > .watermark dd > .shortcuts {
+.mac > .monaco-workbench > .part.editor > .content.empty > .watermark dd > .shortcuts {
 	letter-spacing: 0.15em;
 	font-family: "Lucida Grande", sans-serif;
 }
@@ -65,7 +65,7 @@
 	padding-right: 0.5em;
 }
 
-.monaco-workbench.mac > .part.editor > .content.empty > .watermark dd > .unbound {
+.mac > .monaco-workbench > .part.editor > .content.empty > .watermark dd > .unbound {
 	font-family: "Lucida Grande", sans-serif;
 }
 
diff --git a/src/vs/workbench/parts/welcome/page/electron-browser/welcomePage.css b/src/vs/workbench/parts/welcome/page/electron-browser/welcomePage.css
index e6d6679997cd29791b1ddd8d41630cd086364525..94d52d379fd2685a42ea1fa72d068acca0eb1534 100644
--- a/src/vs/workbench/parts/welcome/page/electron-browser/welcomePage.css
+++ b/src/vs/workbench/parts/welcome/page/electron-browser/welcomePage.css
@@ -228,21 +228,21 @@
 .monaco-workbench > .part.editor > .content .welcomePage .linux-only {
 	display: none;
 }
-.monaco-workbench.mac > .part.editor > .content .welcomePage .mac-only {
+.mac > .monaco-workbench > .part.editor > .content .welcomePage .mac-only {
 	display: initial;
 }
-.monaco-workbench.windows > .part.editor > .content .welcomePage .windows-only {
+.windows > .monaco-workbench > .part.editor > .content .welcomePage .windows-only {
 	display: initial;
 }
-.monaco-workbench.linux > .part.editor > .content .welcomePage .linux-only {
+.linux > .monaco-workbench > .part.editor > .content .welcomePage .linux-only {
 	display: initial;
 }
-.monaco-workbench.mac > .part.editor > .content .welcomePage li.mac-only {
+.mac > .monaco-workbench > .part.editor > .content .welcomePage li.mac-only {
 	display: list-item;
 }
-.monaco-workbench.windows > .part.editor > .content .welcomePage li.windows-only {
+.windows > .monaco-workbench > .part.editor > .content .welcomePage li.windows-only {
 	display: list-item;
 }
-.monaco-workbench.linux > .part.editor > .content .welcomePage li.linux-only {
+.linux > .monaco-workbench > .part.editor > .content .welcomePage li.linux-only {
 	display: list-item;
 }
diff --git a/src/vs/workbench/parts/welcome/walkThrough/electron-browser/walkThroughPart.css b/src/vs/workbench/parts/welcome/walkThrough/electron-browser/walkThroughPart.css
index 64ebb09acd96271a5adc458c0f75dadf84277d89..56a76aa42fe69e1c1f634dbda9ef00ab73222b2c 100644
--- a/src/vs/workbench/parts/welcome/walkThrough/electron-browser/walkThroughPart.css
+++ b/src/vs/workbench/parts/welcome/walkThrough/electron-browser/walkThroughPart.css
@@ -123,13 +123,13 @@
 .monaco-workbench > .part.editor > .content .walkThroughContent .linux-only {
 	display: none;
 }
-.monaco-workbench.mac > .part.editor > .content .walkThroughContent .mac-only {
+.mac > .monaco-workbench > .part.editor > .content .walkThroughContent .mac-only {
 	display: initial;
 }
-.monaco-workbench.windows > .part.editor > .content .walkThroughContent .windows-only {
+.windows > .monaco-workbench > .part.editor > .content .walkThroughContent .windows-only {
 	display: initial;
 }
-.monaco-workbench.linux > .part.editor > .content .walkThroughContent .linux-only {
+.linux > .monaco-workbench > .part.editor > .content .walkThroughContent .linux-only {
 	display: initial;
 }