Hi,
You can also do this with simple css

<style>
[data-kt-app-layout=dark-sidebar] .app-header {background-color: #0d0e12;}
</style>

Hi,

Metronic Demo 1 does not support multiple layout setups. You can use default dark sidebar with light header or dark header without sidebar. It's currently how demo1 supports the layout options.

If you need you can customize the default header to be dark. But for this, you will need to edit the header sass in src/sass/layout/header/_header.scss and Then recompile your assets folder with Gulp or Webpack.

Please note that the build tools are required only in the development environment just to compile the assets when the source folder files are modified. In the hosting/server deployment, you will only need the compile assets, no need to install the build tools dependencies there.

Regards.