Vue Js Change Text Field Color conditionally

<!DOCTYPE html>
<html lang="en">
<head>
  <script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
</head>
<body>
  <div id="app">
    <h3>Vue Js Change Text filed Color conditionally</h3>
    <input type="text" v-model="userInput" :style="{ color: textColor }">
  </div>

h3 {
      margin-bottom: 10px;
      color: #333;
    }

input[type="text"] {
      padding: 10px;
      width: 250px;
      border: 1px solid #ccc;
      border-radius: 5px;
      font-size: 14px;
    }
  </style>

</body>

</html>