diff --git a/packages/plugin-ext/src/main/browser/webviews-main.ts b/packages/plugin-ext/src/main/browser/webviews-main.ts
index 6c3ba9983560f..b2b8f45f2dfb1 100644
--- a/packages/plugin-ext/src/main/browser/webviews-main.ts
+++ b/packages/plugin-ext/src/main/browser/webviews-main.ts
@@ -101,8 +101,10 @@ export class WebviewsMainImpl implements WebviewsMain {
                     }
 
                     this.themeRulesService.setRules(styleElement, this.themeRulesService.getCurrentThemeRules());
+                    contentDocument.body.className = `vscode-${ThemeService.get().getCurrentTheme().id}`;
                     toDispose.push(this.themeService.onThemeChange(() => {
                         this.themeRulesService.setRules(<HTMLElement>styleElement, this.themeRulesService.getCurrentThemeRules());
+                        contentDocument.body.className = `vscode-${ThemeService.get().getCurrentTheme().id}`;
                     }));
                 }
             },