Ask HN: How to “compile” HTML+CSS for minimal page size?

From the perspective of static site generation, is there a tool to compile HTML+CSS in order to minimize download size?

I'm imagining something which takes the following HTML+CSS:

    <style>
    h1{color:red;}
    h2{color:blue;}
    .custom{display:none;}
    .custom2{display:inline;}
    </style>
    ...
    <h2>Hello</h2>
    <div class="custom">
     <p>lorem ipsum</p>
     <p>dolor sit amet</p>
    </div>

And transforms it into this:

    <h2 style="color:blue">Hello</h2>
    <div style="display:none">
     <p>lorem ipsum</p>
     <p>dolor sit amet</p>
    </div>

However, it should not always inline the css styles, because sometimes that would cause the result to be larger than the original, like this:

    <style>
    h1{color:red;}
    h2{color:blue;}
    .custom{display:none;}
    .custom2{display:inline;background-color:yellow;}
    </style>
    ...
    <h2>Hello</h2>
    <div class="custom2">
     <p class="custom2">lorem ipsum</p>
     <p class="custom2">dolor sit amet</p>
    </div>

Here, <p class="custom2"> is shorter than <p style="display:inline;background-color:yellow;">, so it should remain unchanged.

I'm not talking about tools like https://htmlcompressor.com/compressor/ which only remove whitespace, or gzip compression. What I want is something that understands the semantics of HTML+CSS and can intelligently inline iff that reduces the size of the resulting HTML file.