M365 Copilot Chat Full Width

Expands M365 Copilot Chat to the available page width while retaining modest page margins.
Ask a question, post a review, or report the script.
Wrap lines
// ==UserScript==
// @name         M365 Copilot Chat Full Width
// @namespace    http://tampermonkey.net/
// @version      3.1
// @description  Expands M365 Copilot Chat to the available page width while retaining modest page margins.
// @author       hiyun1137 GPT 5.6 Think
// @match        https://m365.cloud.microsoft/*
// @match        https://*.m365.cloud.microsoft/*
// @match        https://microsoft365.com/*
// @match        https://www.microsoft365.com/*
// @grant        GM_addStyle
// @run-at       document-start
// @license      MIT
// ==/UserScript==


(() => {
  const style = document.createElement('style');
  style.textContent = `
    #m365-copilot-app-layout-content {
      width: 100% !important;
      max-width: none !important;
      padding-inline: clamp(12px, 1.5vw, 24px) !important;
      box-sizing: border-box !important;
    }

    /* Widen the real chat branch, located by the stable composer ID. */
    #m365-copilot-app-layout-content :has(#m365-chat-input-shared-container) {
      width: 100% !important;
      max-width: none !important;
      margin-inline: 0 !important;
      box-sizing: border-box !important;
    }

    /* Copilot applies the remaining reading-width cap below that branch. */
    #m365-copilot-app-layout-content div {
      max-width: none !important;
    }

    #m365-chat-input-shared-container,
    [data-test-id="chat-input-wrapper"] {
      width: 100% !important;
      max-width: none !important;
    }

    @media (max-width: 700px) {
      #m365-copilot-app-layout-content { padding-inline: 10px !important; }
    }
  `;
  (document.head || document.documentElement).appendChild(style);
})();