<div class="container">
  <section class="contents">
    我是 section 元素的文本节点（文本内容）
    <p>我是一个 p 元素，同时是 section 元素的子元素</p>
  </section>
</div>

<div class="container">
  <section class="pseudo-elements">
    <p>我是一个 p 元素，同时是 section 元素的子元素</p>
  </section>
</div>

<div class="form">
  <span>display:</span>
  <label for="block">
    <input type="radio" id="block" name="display" value="block" checked />
    block
  </label>
  <label for="contents">
    <input type="radio" name="display" value="contents" id="contents">
    contents
  </label>
</div>

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

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

body {
  width: 100vw;
  min-height: 100vh;
  font-family: "Exo", Arial, sans-serif;
  background-color: #557;
  padding: 2rem 0;
  color: #fff;

  display: flex;
  justify-content: center;
  align-items: center;
  flex-direction: column;
  gap: 20px;
  font-size: clamp(20px, 3vw + 2rem, 40px);
}

.container {
  border: 1px dotted #fff;
}

.contents {
  border: 6px solid #f44336;
  padding: 2rem;
  background-image: linear-gradient(to right, #09f, #90f);
  text-shadow: 1px 1px 0 rgb(0 0 0 / 0.85);
  filter: drop-shadow(8px 8px 1px rgb(0 0 0 / 0.85));
  display: var(--display, block);
  transition: all 0.28s ease-in-out;
}

p {
  background-color: #607d8b;
  padding: 2rem 1rem;
  font-size: 80%;
  color: #cddc39;
}

.pseudo-elements::before {
  content: "我是 section 元素的文本（伪元素生成）！";
}

.form {
  display: flex;
  justify-content: center;
  gap: 10px;
  font-size: 1.5rem;
}

label {
  display: inline-flex;
  align-items: center;
  gap: 5px;
}

input {
  width: 18px;
  height: 18px;
}

const rootEle = document.documentElement;
const inputs = document.querySelectorAll('input[type="radio"]');

inputs.forEach((input) => {
  input.addEventListener("click", (etv) => {
    rootEle.style.setProperty("--display", etv.target.value);
  });
});