Keep the footer pinned to the bottom of the page, even when content isn't tall enough.

page-resize.js

/* Be sure to set your element queries according
to what you actually have in the document! */

(function ($) {
  
  // Bind to the resize event of the window object
  const doResize = () => {
    let wpadmin = 0;
    if ($("#wpadminbar").length) { // in case WP admin bar is present
      wpadmin = $("#wpadminbar").height();
    }
    let footer = $("footer").height();
    let header = $("header").height();
    let screen = $(window).height();

    // Set min-width of main element to:
    // screen height - (footer, header, and maybe admin bar)
    $(".fl-page-content").css(
      "min-height",
      screen - (footer + header + wpadmin)
    );
  }
  
  $(window).on("resize",doResize);
  $(document).ready(doResize);
    
})(jQuery);