<body>
  <div>
    <h1>Frontend Development Series</h1>
  <div>
</body>
h1 {
  font-size: 50px;
  color: pink;
}
div {
  width: 80%;
  height: 70%;
  background-color: black;
}

@media only screen and (max-width: 500px) {
  h1 {
    font-size: 20px;
  }
  div {
    width: 100%;
    background-color: purple;
  }
}

External CSS

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External JavaScript

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