index8.html

<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8" />
        <meta http-equiv="X-UA-Compatible" content="IE=edge" />
        <meta name="viewport" content="width=device-width, initial-scale=1.0" />
        <title>Document</title>
        <script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
    </head>
    <body>
        <div id="app" class="box" v-bind:style="styleObject">sad</div>
        <div :style="{ display: ['-webkit-box', '-ms-flexbox', 'flex'] }"></div>
        <script>
            var vm = new Vue({
                el: "#app",
                data: {
                    styleObject: {
                        activeColor: "red",
                        fontSize: 30,
                    },
                },
            });
        </script>   
        <style>
            .box {
                width: 200px;
                height: 200px;
                background: #fff000;    
            }
        </style>
    </body>
</html>