index.html

<!DOCTYPE html>

<html>
    <head>
        <meta charset="UTF-8">
        <title>CompassArena</title>
    </head>

<style>
    body{
        margin: 0;
    }

    iframe{      
        display: block;  /* iframes are inline by default */   
        height: 100vh;  /* Set height to 100% of the viewport height */   
        width: 100vw;  /* Set width to 100% of the viewport width */     
        border: none; /* Remove default border */
    }
</style>

<body>
    <iframe src="https://opencompass.org.cn/arena/platform_en" title="CompassArena"></iframe>
</body>

</html>