Inserting CSS Stylesheet into Page from Chrome Extension

Question

got what I hopefully think is a simple issue.

I'm working on a very simple chrome extension, but for some reason, I can't get past the following error when I try to run the code in my content script:

23111634:1 Error in event handler: TypeError: Cannot read properties of undefined (reading 'insertCSS')

My code in that content script:

chrome.runtime.onMessage.addListener(
    function(request, sender, sendResponse) {
        console.log(request)
        if( request.command === "hideCompanies" ) {
            start(request.tab);
        }
    }
);

function start(tab){
    alert("inserting css")
    chrome.scripting.insertCSS({
        target: {tabId: tab},
        files: ['customhs.css']
    })
    alert("DONE")
    sendResponse({farewell: true})
}

the messaging works, just it seems to error out on chrome.scripting.insertCSS. Here is my manifest:

{
  "manifest_version": 3,
  "name": "",
  "description": ".",
  "version": "1.0",
  "action": {
    "default_icon": "toggle.png",
    "default_popup": "popup.html"
  },
  "permissions": ["storage", "activeTab", "scripting", "tabs"],
  "background": {
    "service_worker": "toggles.js"
  },
  "content_scripts": [
    {
      "matches": ["https://*.myownwebsite.com/*"],
      "js": ["toggles.js"]
    }
  ]
}

and here is my popup js:

function popup() {
    chrome.tabs.query({currentWindow: true, active: true}, function (tabs){
        var activeTab = tabs[0];
        chrome.tabs.sendMessage(activeTab.id, {"command": "hideCompanies", "tab": activeTab.id});
    });
}

document.addEventListener("DOMContentLoaded", function() {
    document.getElementById("companies").addEventListener("click", popup);
});

Appreciate any and all guidance!