github.com/containers/podman/v5@v5.1.0-rc1/docs/source/_static/custom.css

h2,h3,h4,h5,h6{
    /*  Sphinx doesn't respect using a h4 header without using h1,h2,h3.
        The flag names will be rendered as h2 and by default way to big
        so make the font size for all headers except h1 smaller.
    */
    font-size: 120% !important;
}