Simple Chrome extension that replaces user stylesheets (removed in Chrome 33).

README.md

Installation

Save manifest.json and style.css in a directory on your machine.

Click the Chrome menu icon and select Extensions from the Tools menu. Ensure that the "Developer mode" checkbox in the top right-hand corner is checked. Click "Load unpacked extension" and select to your newly created directory.

Read more

manifest.json

{
  "manifest_version": 2,
  "name": "User Stylesheet",
  "version": "0.1",
  "content_scripts": [{
    "matches": ["https://yoururl.com/*"],
    "css": ["style.css"]
  }]
}

style.css

body {
  background-color: magenta;
}