src/vs/workbench/services/themes/browser/workbenchThemeService.ts/WorkbenchThemeService/updateDynamicCSSRules
class WorkbenchThemeService:	private updateDynamicCSSRules(themeData: IColorTheme) {
		const cssRules = new Set<string>();
		const ruleCollector = {
			addRule: (rule: string) => {
				if (!cssRules.has(rule)) {
					cssRules.add(rule);
				}
			}
		};
		ruleCollector.addRule(`.monaco-workbench { forced-color-adjust: none; }`);
		themingRegistry.getThemingParticipants().forEach(p => p(themeData, ruleCollector, this.environmentService));

		const colorVariables: string[] = [];
		for (const item of getColorRegistry().getColors()) {
			const color = themeData.getColor(item.id, true);
			if (color) {
				colorVariables.push(`${asCssVariableName(item.id)}: ${color.toString()};`);
			}
		}
		ruleCollector.addRule(`.monaco-workbench { ${colorVariables.join('\n')} }`);

		_applyRules([...cssRules].join('\n'), colorThemeRulesClassName);
	}