test.html

<head>
  <style>
    :root {
      /* --feedbackfin-primary-color: #007aff; */
      /* --feedbackfin-primary-color-text: #fff; */
    }

    body {
      font-family: system-ui;
      display: grid;
      place-items: flex-end;
      height: 200vh;
    }

    * {
      box-sizing: border-box;
    }
  </style>
</head>

<body>
  <button onclick="toggleTheme()" style="position: fixed; top: 8px; left: 8px">
    Toggle theme
  </button>
  <button data-feedbackfin-button>Feedback</button>

  <script src="./dist/index.umd.js"></script>
  <script>
    // import "./dist/index.modern.js";

    function toggleTheme() {
      document.body.setAttribute(
        "data-theme",
        document.body.getAttribute("data-theme") === "dark" ? "light" : "dark"
      );
    }

    // document
    //   .querySelector("button")
    //   .addEventListener("click", feedbackfin.open);
  </script>
</body>