Preview:
window.addEventListener('load', function () {
  $(".hs-form .hs-form-field .hs-input").focus(function () {
    $(this).parent().parent().removeClass("blured");
    $(this).parent().parent().addClass("focused");
  }).blur(function () {
    $(this).parent().parent().removeClass("focused");
    $(this).parent().parent().addClass("blured");
  });

  $('.hs-form .hs-form-field .hs-input').on('keyup keydown', function () {
    if ($(this).val() !== "") {
      $(this).parent().parent().removeClass("blank");
      $(this).parent().parent().addClass("filled");
    }
    else {
      $(this).parent().parent().removeClass("focused");
      $(this).parent().parent().addClass("blank");
    }
  });
  $('.hs-form .hs-form-field .hs-input').blur(function () {
    if ($(this).val() == "") {
      $(this).parent().parent().removeClass("filled");
      $(this).parent().parent().addClass("blank");
    }
  });
});
downloadDownload PNG downloadDownload JPEG downloadDownload SVG

Tip: You can change the style, width & colours of the snippet with the inspect tool before clicking Download!

Click to optimize width for Twitter