Vue Js Input allow only small letter

<!DOCTYPE html>
<html>

<head>
  <script src="https://unpkg.com/vue@3/dist/vue.global.js"></script>
</head>
<body>
  <div id="app">
    <h3>Vue Js Textbox allow only small letter</h3>
    <input type="text" v-model="inputValue" @input="handleInput" />

</div>
  <script>
    const app = Vue.createApp({
       data() {
        return {
          inputValue: ''
        };
      },
      methods: {
        handleInput() {
          this.inputValue = this.inputValue.toLowerCase();
        }
      }
    });
    app.mount('#app');
  </script>
  <style>
     #app {
      width: 400px;
      margin: 0 auto;
      box-shadow: 0 1px 2px 0 rgba(0, 0, 0, 0.12), 0 2px 4px 0 rgba(0, 0, 0, 0.24);
      text-align: center;
      padding: 20px;
      height: 100%;
    }

.error-message {
      color: red;
      font-size: 14px;
      margin-top: 5px;
    }

input[type="text"] {
      padding: 10px;
      font-size: 16px;
      border: 1px solid #ccc;
      border-radius: 4px;
      outline-color: blue;
      /* Change the color as desired */
    }
  </style>
</body>
</html>