JSFiddle - React, Tailwind, and code Playground

HTML

<script async src="https://unpkg.com/es-module-shims@1.6.3/dist/es-module-shims.js"></script>

<script type="importmap">
  {
    "imports": {
      "three": "https://unpkg.com/three/build/three.module.js",
      "three/addons/": "https://unpkg.com/three/examples/jsm/"
    }
  }
</script>

<body>
<div class="menu-container">

</div>
</body>

CSS

body {
  margin: 0;
  position: relative;
}

div {
  background-color: red;
  opacity: 0.3;
  width: 10px;
  height: 10px;
  
  position: absolute;
  left: 50%;
  top: 50%;
}

JavaScript

import * as THREE from 'three';

const scene = new THREE.Scene();
const camera = new THREE.PerspectiveCamera( 75, window.innerWidth / window.innerHeight, 0.1, 1000 );

const renderer = new THREE.WebGLRenderer();
renderer.setSize( window.innerWidth, window.innerHeight );
document.body.appendChild( renderer.domElement );

const geometry = new THREE.BoxGeometry( 1, 1, 1 );
const material = new THREE.MeshBasicMaterial( { color: 0x00ff00 } );
const cube = new THREE.Mesh( geometry, material );
scene.add( cube );

camera.position.z = 5;

const cubeSize = new THREE.Vector3();

const box3 = new THREE.Box3();
box3.setFromObject(cube);

cube.updateMatrixWorld(true)
box3.applyMatrix4(cube.matrixWorld);
box3.getSize(cubeSize);
cubeSize.project(camera);

/* cube.position.z += 0.01; */

console.log(cubeSize);

const x = (cubeSize.x * 0.5 + 0.5) * (window.innerWidth / 2);
const y = (cubeSize.y * -0.5 + 0.5) * (window.innerHeight / 2);

const container = document.querySelector('.menu-container');
if (container) {
  container.style.width = `${x}px`;
  container.style.height = `${y}px`;
  container.style.transform = `translate(-50%, -50%)`;
}


function animate() {

  requestAnimationFrame( animate );
  

  renderer.render( scene, camera );

}

animate();