Vue Textarea Fullscreen on Click

<!DOCTYPE html>
<html>
<head>
    <script src="https://unpkg.com/vue@3/dist/vue.global.js"></script>
</head>
<body>
    <div id="app">
        <h3>Vue Textarea Fullscreen on click</h3>
        <div :class="{ fullscreen: fullscreen }">
            <button @click="toggleFullscreen()">Toggle Fullscreen</button><br>
            <textarea ref="textarea"></textarea>
        </div>
    </div>
    <script type="module">
        const app = Vue.createApp({
            data() {
                return {
                    fullscreen: false,
                };
            },
            methods: {
                toggleFullscreen() {
                    this.fullscreen = !this.fullscreen;
                    const textarea = this.$refs.textarea;
                    if (this.fullscreen) {
                        textarea.style.width = '100%';
                        textarea.style.height = '100%';
                    } else {
                        textarea.style.width = 'auto';
                        textarea.style.height = 'auto';
                    }
                },

},
        });app.mount("#app");
    </script>
    <style scoped>
        body {
            margin: 0;
            padding: 0;
            font-family: Arial, sans-serif;
            font-size: 16px;
            line-height: 1.5;
        }

#app {
            display: flex;
            flex-direction: column;
            align-items: center;
            justify-content: center;
            height: 100vh;
        }

h3 {
            margin-top: 0;
            font-weight: bold;
            text-align: center;
        }

button {
            padding: 10px 20px;
            font-size: 16px;
            font-weight: bold;
            background-color: #007bff;
            color: #fff;
            border: none;
            border-radius: 4px;
            cursor: pointer;
            margin-bottom: 20px;
        }

textarea {
            padding: 20px;
            font-size: 16px;
            border-radius: 4px;
            box-shadow: none;
            width: 100%;
            height: 300px;
            background-color: #fff;
            transition: all 0.3s ease;
        }

.fullscreen {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            border: none;
            background-color: #000;
        }
    </style>
</body>
</html>