Reminds me of the “Shakespearean Templates“ [1] from the Yesod web framework [2].

[1]: https://www.oreilly.com/library/view/developing-web-applicat...

[2]: https://www.yesodweb.com/

Copied below to save you a click:

Hamlet (HTML)

    $doctype 5
    <html>
        <head>
            <title>#{pageTitle} - My Site
            <link rel=stylesheet href=@{Stylesheet}>
        <body>
            <h1 .page-title>#{pageTitle}
            <p>Here is a list of your friends:
            $if null friends
                <p>Sorry, I lied, you don't have any friends.
            $else
                <ul>
                    $forall Friend name age <- friends
                        <li>#{name} (#{age} years old)
            <footer>^{copyright}

Cassius (CSS)

    #myid
        color: #{red}
        font-size: #{bodyFontSize}
    foo bar baz
        background-image: url(@{MyBackgroundR})

Lucius (CSS)

    section.blog {
        padding: 1em;
        border: 1px solid #000;
        h1 {
            color: #{headingColor};
        }
    }

Julius (JavaScript)

    $(function(){
        $("section.#{sectionClass}").hide();
        $("#mybutton").click(function(){document.location = "@{SomeRouteR}";});
        ^{addBling}
    });

For those curious, the above is implemented in the metaprogramming framework of Template Haskell.