Metronic supports full Dark Mode that you can preview here and easiliy setup following the below instructions.
--dark-modeflag in
											theme/tools/folder to generate the Dark Mode of CSS files.
											
gulp --dark-mode --demo1
													
npm run build --dark-mode --demo1
													style.dark.bundle.cssand
											plugins.dark.bundle.cssare generated in assets folder:
											
<!--begin::Global Stylesheets Bundle(used by all pages)-->
<link href="assets/plugins/global/plugins.dark.bundle.css" rel="stylesheet" type="text/css" />
<link href="assets/css/style.dark.bundle.css" rel="stylesheet" type="text/css" />
<!--end::Global Stylesheets Bundle-->
													dark-modeclass name to the
											<body>tag. Keep other
											bodyclass names.
											
<body class="dark-mode ...">
<!-- HTML content -->
</body>
													KTApp.setThemeMode(mode String, callback Function)to set the theme mode dynamically without refreshing the page:
											
KTApp.setThemeMode("dark", function() {
    console.log("changed to dark mode");
}); // set dark mode
KTApp.setThemeMode("light", function() {
    console.log("changed to light mode");
}); // set light mode
													-darkprefix to the file name:
											
<img src="assets/media/illustrations/sketchy-1/1.png"/>
													
<img src="assets/media/illustrations/sketchy-1/1-dark.png"/>