<div class="data-container">
  <span class="btn">Hover Me</span>
</div>
body {
  margin: 0;
  padding: 0;
}

.btn {
  cursor: pointer;
  padding: 10px 20px;
  background: white;
  font-size: 28px;
  border-top-right-radius: 10px;
  border-bottom-left-radius: 10px;
  transition: all 1s;
}
.btn:hover {
  background: lightblue;
}

.data-container {
  background: #ffebee;
  height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
}

External CSS

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External JavaScript

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