<div class="container">
  <ul>
    <li>W3cplus.com</li>
  </ul>
</div>

<div class="form">
  <label for="content">content:</label>
  <select name="content" id="contet">
    <optgroup label="字符">
      <option value="' '">' '</option>
      <option value="'Go!'">Go!</option>
      <option value="'Go! ' ' Go!'">'Go! ' ' Go!'</option>
    </optgroup>
    <optgroup label="HTML实体符">
      <option value="'➤'">➤</option>
      <option value="'❢' '𝄞'">'❢' '𝄞'</option>
      <option value="'\2762'">'\2762'</option>
      <option value="'\2763' '\2141'">'\2763' '\2141'</option>
    </optgroup>
    <optgroup label="表情符号">
      <option value="'🔥'">🔥</option>
      <option value="'🐻' '🐶'">'🐻' '🐶'</option>
      <option value="'\01F33A'">'\01F33A'</option>
      <option value="'\01F42C' '\01F41F'">'\01F42C' '\01F41F'</option>
    </optgroup>
    <optgroup label="引号">
      <option value="open-quote">open-quote</option>
      <option value="close-quote">close-quote</option>
    </optgroup>
    <optgroup label="图片">
      <option value="url('//www.w3cplus.com/sites/default/files/blogs/2021/2108/rocket.svg')">url(//www.w3cplus.com/sites/default/files/blogs/2021/2108/rocket.svg)</option>
      <option value="image-set('url(//www.w3cplus.com/sites/default/files/blogs/2021/2108/rocket.svg)' 1x)">image-set(url(//www.w3cplus.com/sites/default/files/blogs/2021/2108/rocket.svg) 1x)</option>
    </optgroup>
  </select>
</div>

@import url("https://fonts.googleapis.com/css2?family=Exo:wght@600&display=swap");

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  inline-size: 100vw;
  min-block-size: 100vh;

  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 10px;
  font-family: "Exo", Arial, sans-serif;
  background-color: #f7f7f7;
  line-height: 2;
}

.container {
  padding: 40px;
  background: #fff;
  box-sizing: border-box;
  box-shadow: 0 2px 4px rgb(0 0 0 / 20%);
  min-width: 40vw;
  max-width: 40vw;
  border-radius: 5px;
  position: relative;
}

select {
  max-width: 200px;
}

:lang * {
  quotes: "« " " »";
}

:root {
  --content: "";
}

li::after {
  content: var(--content);
  margin-left: 5px;
}

const rootEle = document.documentElement;
const select = document.getElementById("contet");

select.addEventListener("change", (etv) => {
  rootEle.style.setProperty("--content", etv.target.value);
});